Class: ActiveRecord::ConnectionAdapters::IBM_DBAdapter

Inherits:
AbstractAdapter
  • Object
show all
Includes:
QueryCache
Defined in:
lib/active_record/connection_adapters/ibm_db_adapter.rb,
lib/active_record/connection_adapters/ibm_db_pstmt.rb

Overview

The IBM_DB Adapter requires the native Ruby driver (ibm_db) for IBM data servers (ibm_db.so). config the hash passed as an initializer argument content:

mandatory parameters 

adapter:         'ibm_db'        // IBM_DB Adapter name
username:        'db2user'       // data server (database) user
password:        'secret'        // data server (database) password
database:        'ARUNIT'        // remote database name (or catalog entry alias)

optional (highly recommended for data server auditing and monitoring purposes)

schema:          'rails123'      // name space qualifier
account:         'tester'        // OS account (client workstation)
app_user:        'test11'        // authenticated application user
application:     'rtests'        // application name
workstation:     'plato'         // client workstation name

remote TCP/IP connection (required when no local database catalog entry available)

host:            'socrates'      // fully qualified hostname or IP address
port:            '50000'         // data server TCP/IP port number
security:        'SSL'           // optional parameter enabling SSL encryption -
                                 // - Available only from CLI version V95fp2 and above
authentication:  'SERVER'        // AUTHENTICATION type which the client uses - 
                                 // - to connect to the database server. By default value is SERVER
timeout:         10              // Specifies the time in seconds (0 - 32767) to wait for a reply from server -
                                 //- when trying to establish a connection before generating a timeout

Parameterized Queries Support

parameterized:  false            // Specifies if the prepared statement support of 
                                 //- the IBM_DB Adapter is to be turned on or off

When schema is not specified, the username value is used instead. The default setting of parameterized is false.

Defined Under Namespace

Classes: BindSubstitution

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from QueryCache

included, #prepared_select_with_query_cache

Constructor Details

#initialize(connection, ar3, logger, config, conn_options) ⇒ IBM_DBAdapter

Returns a new instance of IBM_DBAdapter.



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 750

def initialize(connection, ar3, logger, config, conn_options)
  # Caching database connection configuration (+connect+ or +reconnect+ support)\
	@config = config
  @connection       = connection
		@isAr3            = ar3
  @conn_options     = conn_options
  @database         = config[:database]
  @username         = config[:username]
  @password         = config[:password]
  if config.has_key?(:host)
    @host           = config[:host]
    @port           = config[:port] || 50000 # default port
  end
  @schema           = config[:schema]
  @security         = config[:security] || nil
  @authentication   = config[:authentication] || nil
  @timeout          = config[:timeout] || 0  # default timeout value is 0

  @app_user = @account = @application = @workstation = nil
  # Caching database connection options (auditing and billing support)
  @app_user         = conn_options[:app_user]     if conn_options.has_key?(:app_user)
  @account          = conn_options[:account]      if conn_options.has_key?(:account)
  @application      = conn_options[:application]  if conn_options.has_key?(:application)
  @workstation      = conn_options[:workstation]  if conn_options.has_key?(:workstation)
  
  @sql                  = []
  @sql_parameter_values = [] #Used only if pstmt support is turned on

  @handle_lobs_triggered = false

  # Calls the parent class +ConnectionAdapters+' initializer
  # which sets @connection, @logger, @runtime and @last_verification
  super(@connection, logger, @config)

  if @connection
    server_info = IBM_DB.server_info( @connection )
    if( server_info )
      case server_info.DBMS_NAME
        when /DB2\//i             # DB2 for Linux, Unix and Windows (LUW)
          case server_info.DBMS_VER
            when /09.07/i          # DB2 Version 9.7 (Cobra)
              @servertype = IBM_DB2_LUW_COBRA.new(self, @isAr3)
            when /10./i #DB2 version 10.1 and above
              @servertype = IBM_DB2_LUW_COBRA.new(self, @isAr3)
            else                  # DB2 Version 9.5 or below
              @servertype = IBM_DB2_LUW.new(self, @isAr3)
          end
        when /DB2/i               # DB2 for zOS
          case server_info.DBMS_VER
            when /09/             # DB2 for zOS version 9 and version 10
              @servertype = IBM_DB2_ZOS.new(self, @isAr3)
            when /10/
              @servertype = IBM_DB2_ZOS.new(self, @isAr3)
            when /08/             # DB2 for zOS version 8
              @servertype = IBM_DB2_ZOS_8.new(self, @isAr3)
            else                  # DB2 for zOS version 7
              raise "Only DB2 z/OS version 8 and above are currently supported"
          end
        when /AS/i                # DB2 for i5 (iSeries)
          @servertype = IBM_DB2_I5.new(self, @isAr3)
        when /IDS/i               # Informix Dynamic Server
          @servertype = IBM_IDS.new(self, @isAr3)
        else
          log( "server_info", "Forcing servertype to LUW: DBMS name could not be retrieved. Check if your client version is of the right level")
          warn "Forcing servertype to LUW: DBMS name could not be retrieved. Check if your client version is of the right level"
          @servertype = IBM_DB2_LUW.new(self, @isAr3)
      end
    else
      error_msg = IBM_DB.getErrormsg( @connection, IBM_DB::DB_CONN )
      IBM_DB.close( @connection )
      raise "Cannot retrieve server information: #{error_msg}"
    end
  end

  # Executes the +set schema+ statement using the schema identifier provided
  @servertype.set_schema(@schema) if @schema && @schema != @username

  # Check for the start value for id (primary key column). By default it is 1
  if config.has_key?(:start_id)
    @start_id = config[:start_id]
  else
    @start_id = 1
  end

  #Check Arel version
  begin
    @arelVersion = Arel::VERSION.to_i
  rescue
    @arelVersion = 0
  end

  if(@arelVersion >=  3 )
    @visitor = Arel::Visitors::IBM_DB.new self
  end
		
  if(config.has_key?(:parameterized) && config[:parameterized] == true)			 
    @pstmt_support_on = true
    @prepared_statements = true
    @set_quoted_literal_replacement = IBM_DB::QUOTED_LITERAL_REPLACEMENT_OFF
  else		  
    @pstmt_support_on = false
    @prepared_statements = false
    @set_quoted_literal_replacement = IBM_DB::QUOTED_LITERAL_REPLACEMENT_ON
  end
end

Instance Attribute Details

#account ⇒ Object

Returns the value of attribute account.



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 738

def 
  @account
end

#app_user ⇒ Object

Returns the value of attribute app_user.



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 738

def app_user
  @app_user
end

#application ⇒ Object

Returns the value of attribute application.



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 738

def application
  @application
end

#connection ⇒ Object (readonly)

Returns the value of attribute connection.



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 736

def connection
  @connection
end

#handle_lobs_triggered ⇒ Object

Returns the value of attribute handle_lobs_triggered.



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 737

def handle_lobs_triggered
  @handle_lobs_triggered
end

#pstmt_support_on ⇒ Object (readonly)

Returns the value of attribute pstmt_support_on.



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 739

def pstmt_support_on
  @pstmt_support_on
end

#schema ⇒ Object

Returns the value of attribute schema.



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 738

def schema
  @schema
end

#servertype ⇒ Object (readonly)

Returns the value of attribute servertype.



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 736

def servertype
  @servertype
end

#set_quoted_literal_replacement ⇒ Object (readonly)

Returns the value of attribute set_quoted_literal_replacement.



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 739

def set_quoted_literal_replacement
  @set_quoted_literal_replacement
end

#sql ⇒ Object

Returns the value of attribute sql.



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 737

def sql
  @sql
end

#sql_parameter_values ⇒ Object

Returns the value of attribute sql_parameter_values.



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 737

def sql_parameter_values
  @sql_parameter_values
end

#workstation ⇒ Object

Returns the value of attribute workstation.



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 738

def workstation
  @workstation
end

Class Method Details

.visitor_for(pool) ⇒ Object 



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 904

def self.visitor_for(pool)
  Arel::Visitors::IBM_DB.new(pool)
end

Instance Method Details

#active? ⇒ Boolean

Tests the connection status

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 959

def active?
  IBM_DB.active @connection
  rescue
    false
end

#adapter_name ⇒ Object

Name of the adapter



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 742

def adapter_name
  'IBM_DB'
end

#add_limit_offset!(sql, options) ⇒ Object

Modifies a sql statement in order to implement a LIMIT and an OFFSET. A LIMIT defines the number of rows that should be fetched, while an OFFSET defines from what row the records must be fetched. IBM data servers implement a LIMIT in SQL statements through: FETCH FIRST n ROWS ONLY, where n is the number of rows required. The implementation of OFFSET is more elaborate, and requires the usage of subqueries and the ROW_NUMBER() command in order to add row numbering as an additional column to a copy of the existing table.

Examples

add_limit_offset!(‘SELECT * FROM staff’, => 10) generates: “SELECT * FROM staff FETCH FIRST 10 ROWS ONLY”

add_limit_offset!(‘SELECT * FROM staff’, => 10, :offset => 30) generates “SELECT O.* FROM (SELECT I.*, ROW_NUMBER() OVER () sys_rownum FROM (SELECT * FROM staff) AS I) AS O WHERE sys_row_num BETWEEN 31 AND 40”



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1545

def add_limit_offset!(sql, options)
  limit = options[:limit]
  offset = options[:offset]

  # if the limit is zero
  if limit && limit == 0
    # Returns a query that will always generate zero records
    # (e.g. WHERE sys_row_num BETWEEN 1 and 0)
    if( @pstmt_support_on )
      sql = @servertype.query_offset_limit!(sql, 0, limit, options)
    else
      sql = @servertype.query_offset_limit(sql, 0, limit)
    end
  # If there is a non-zero limit
  else
    # If an offset is specified builds the query with offset and limit,
    # otherwise retrieves only the first +limit+ rows
    if( @pstmt_support_on )
      sql = @servertype.query_offset_limit!(sql, offset, limit, options)
    else
      sql = @servertype.query_offset_limit(sql, offset, limit)
    end
  end
  # Returns the sql query in any case
  sql
end

#alter_foreign_keys(tables, not_enforced) ⇒ Object 



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 2379

def alter_foreign_keys(tables, not_enforced)
     enforced = not_enforced ? 'NOT ENFORCED' : 'ENFORCED'
     tables.each do |table|
       foreign_keys(table).each do |fk|
         execute("ALTER TABLE #{@servertype.set_case(fk.from_table)} ALTER FOREIGN KEY #{@servertype.set_case(fk.name)} #{enforced}")			
       end
     end
end

#begin_db_transaction ⇒ Object

Begins the transaction (and turns off auto-committing)



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1499

def begin_db_transaction
  # Turns off the auto-commit
  IBM_DB.autocommit(@connection, IBM_DB::SQL_AUTOCOMMIT_OFF)
end

#build_conn_str_for_dbops ⇒ Object 



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1748

def build_conn_str_for_dbops()
  connect_str = "DRIVER={IBM DB2 ODBC DRIVER};ATTACH=true;"
  if(!@host.nil?)
    connect_str << "HOSTNAME=#{@host};"
    connect_str << "PORT=#{@port};"
    connect_str << "PROTOCOL=TCPIP;"
  end
  connect_str << "UID=#{@username};PWD=#{@password};"
  return connect_str
end

#change_column(table_name, column_name, type, options = {}) ⇒ Object

Changes the column’s definition according to the new options. See TableDefinition#column for details of the options you can use.

Examples
change_column(:suppliers, :name, :string, :limit => 80)
change_column(:accounts, :description, :text)



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 2420

def change_column(table_name, column_name, type, options = {})
  @servertype.change_column(table_name, column_name, type, options)
end

#change_column_default(table_name, column_name, default) ⇒ Object

Sets a new default value for a column. This does not set the default value to NULL, instead, it needs DatabaseStatements#execute which can execute the appropriate SQL statement for setting the value.

Examples

change_column_default(:suppliers, :qualification, 'new')
change_column_default(:accounts, :authorized, 1)

Method overriden to satisfy IBM data servers syntax.



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 2451

def change_column_default(table_name, column_name, default)
  @servertype.change_column_default(table_name, column_name, default)
end

#change_column_null(table_name, column_name, null, default = nil) ⇒ Object

Changes the nullability value of a column



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 2456

def change_column_null(table_name, column_name, null, default = nil)
  @servertype.change_column_null(table_name, column_name, null, default)
end

#columns(table_name) ⇒ Object

Returns an array of Column objects for the table specified by table_name



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 2195

def columns(table_name)
# to_s required because it may be a symbol.
  table_name = @servertype.set_case(table_name.to_s)
				
  # Checks if a blank table name has been given.
  # If so it returns an empty array
  return [] if table_name.strip.empty?
  # +columns+ will contain the resulting array
  columns = []
  # Statement required to access all the columns information
  stmt = IBM_DB.columns( @connection, nil, 
                             @servertype.set_case(@schema), 
                             @servertype.set_case(table_name) )
  if(stmt)
    begin
      # Fetches all the columns and assigns them to col.
      # +col+ is an hash with keys/value pairs for a column
      while col = IBM_DB.fetch_assoc(stmt)
        column_name = col["column_name"].downcase
        # Assigns the column default value.
        column_default_value = col["column_def"]
        # If there is no default value, it assigns NIL
        column_default_value = nil if (column_default_value && column_default_value.upcase == 'NULL')
        # If default value is IDENTITY GENERATED BY DEFAULT (this value is retrieved in case of id columns)
        column_default_value = nil if (column_default_value && column_default_value.upcase =~ /IDENTITY GENERATED BY DEFAULT/i)
        # Removes single quotes from the default value
        column_default_value.gsub!(/^'(.*)'$/, '\1') unless column_default_value.nil?
        # Assigns the column type
        column_type = col["type_name"].downcase
        # Assigns the field length (size) for the column
			  
			  original_column_type = "#{column_type}"
			  
        column_length = col["column_size"]
        column_scale = col["decimal_digits"]
        # The initializer of the class Column, requires the +column_length+ to be declared 
        # between brackets after the datatype(e.g VARCHAR(50)) for :string and :text types. 
        # If it's a "for bit data" field it does a subsitution in place, if not
        # it appends the (column_length) string on the supported data types
        unless column_length.nil? || 
               column_length == '' || 
               column_type.sub!(/ \(\) for bit data/i,"(#{column_length}) FOR BIT DATA") || 
               !column_type =~ /char|lob|graphic/i
          if column_type =~ /decimal/i
            column_type << "(#{column_length},#{column_scale})"
          elsif column_type =~ /smallint|integer|double|date|time|timestamp|xml|bigint/i
            column_type << ""  # override native limits incompatible with table create
          else
            column_type << "(#{column_length})"
          end
        end
        # col["NULLABLE"] is 1 if the field is nullable, 0 if not.
        column_nullable = (col["nullable"] == 1) ? true : false
        # Make sure the hidden column (db2_generated_rowid_for_lobs) in DB2 z/OS isn't added to the list
        if !(column_name =~ /db2_generated_rowid_for_lobs/i)
          # Pushes into the array the *IBM_DBColumn* object, created by passing to the initializer
          # +column_name+, +default_value+, +column_type+ and +column_nullable+.
          #if(@arelVersion >=  6 )				
			
 #cast_type = lookup_cast_type(column_type)
				
				ruby_type = simplified_type2(column_type)
				precision = extract_precision(ruby_type)
				
				#type = type_map.lookup(column_type)
				sql_type = type_to_sql(column_type, column_length, precision, column_scale)
					  
				sqltype_metadata = SqlTypeMetadata.new(					
					#sql_type: sql_type,
					sql_type: original_column_type,
					type: ruby_type,
					limit: column_length,
					precision: precision,
					scale: column_scale,
				)
				
				columns << Column.new(column_name, column_default_value, sqltype_metadata, column_nullable, table_name)
			
				#else
				#	columns << IBM_DBColumn.new(column_name, column_default_value, column_type, column_nullable)
				#end
        end
      end
    rescue StandardError => fetch_error # Handle driver fetch errors
      error_msg = IBM_DB.getErrormsg(stmt, IBM_DB::DB_STMT )
      if error_msg && !error_msg.empty?
        raise "Failed to retrieve column metadata during fetch: #{error_msg}"
      else
        error_msg = "An unexpected error occurred during retrieval of column metadata"
        error_msg = error_msg + ": #{fetch_error.message}" if !fetch_error.message.empty?
        raise error_msg
      end
    ensure  # Free resources associated with the statement
      IBM_DB.free_stmt(stmt) if stmt
    end
  else  # Handle driver execution errors
    error_msg = IBM_DB.getErrormsg(@connection, IBM_DB::DB_CONN )
    if error_msg && !error_msg.empty?
      raise "Failed to retrieve column metadata due to error: #{error_msg}"
    else
      raise StandardError.new('An unexpected error occurred during retrieval of columns metadata')
    end
  end
  # Returns the columns array
  return columns
end

#columns_for_distinct(columns, orders) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 2433

def columns_for_distinct(columns, orders) #:nodoc:
  order_columns = orders.reject(&:blank?).map{ |s|
	  # Convert Arel node to string
	  s = s.to_sql unless s.is_a?(String)
	  # Remove any ASC/DESC modifiers
	  s.gsub(/\s+(?:ASC|DESC)\b/i, '')
	   .gsub(/\s+NULLS\s+(?:FIRST|LAST)\b/i, '')
	}.reject(&:blank?).map.with_index { |column, i| "#{column} AS alias_#{i}" }			
  [super, *order_columns].join(', ')
end

#commit_db_transaction ⇒ Object

Commits the transaction and turns on auto-committing



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1505

def commit_db_transaction
  # Commits the transaction
  IBM_DB.commit @connection rescue nil
  # Turns on auto-committing
  IBM_DB.autocommit @connection, IBM_DB::SQL_AUTOCOMMIT_ON
end

#create_database(dbName, codeSet = nil, mode = nil) ⇒ Object 



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1782

def create_database(dbName, codeSet=nil, mode=nil)
  connect_str = build_conn_str_for_dbops()

  #Ensure connection is closed before trying to drop a database.
  #As a connect call would have been made by call seeing connection in active
  disconnect!

  begin
    createConn = IBM_DB.connect(connect_str, '', '')
  rescue StandardError => connect_err
    raise "Failed to connect to server due to: #{connect_err}"
  end

  if(IBM_DB.createDB(createConn,dbName,codeSet,mode))
    IBM_DB.close(createConn)
    return true
  else
    error = IBM_DB.getErrormsg(createConn, IBM_DB::DB_CONN)
    IBM_DB.close(createConn)
    raise "Could not create Database due to: #{error}"
  end
end

#create_table(name, options = {}) ⇒ Object

DATABASE STATEMENTS



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1023

def create_table(name, options = {})
  @servertype.setup_for_lob_table
  #Table definition is complete only when a unique index is created on the primarykey column for DB2 V8 on zOS
  
  #create index on id column if options[:id] is nil or id ==true
  #else check if options[:primary_key]is not nil then create an unique index on that column
  if  !options[:id].nil? || !options[:primary_key].nil?
    if (!options[:id].nil? && options[:id] == true)
        @servertype.create_index_after_table(name,"id")
    elsif !options[:primary_key].nil?
        @servertype.create_index_after_table(name,options[:primary_key].to_s)
    end
  else
      @servertype.create_index_after_table(name,"id")
  end
    super(name, options)
end

#default_sequence_name(table, column) ⇒ Object

method add_limit_offset!



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1572

def default_sequence_name(table, column) # :nodoc:
  "#{table}_#{column}_seq"
end

#disable_referential_integrity ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 2366

def disable_referential_integrity #:nodoc:
    if supports_disable_referential_integrity?
      alter_foreign_keys(tables, true)
    end

    yield
  ensure
    if supports_disable_referential_integrity?
      alter_foreign_keys(tables, false)
    end
		
end

#disconnect! ⇒ Object

Closes the current connection



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1010

def disconnect!
  # Attempts to close the connection. The methods will return:
  # * true if succesfull
  # * false if the connection is already closed
  # * nil if an error is raised
  return nil if @connection.nil? || @connection == false
  IBM_DB.close(@connection) rescue nil
end

#distinct(columns, order_by) ⇒ Object

Add distinct clause to the sql if there is no order by specified



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 2425

def distinct(columns, order_by)
  if order_by.nil?
    "DISTINCT #{columns}" 
  else
    "#{columns}"
  end
end

#drop_database(dbName) ⇒ Object 



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1759

def drop_database(dbName)
  connect_str = build_conn_str_for_dbops()

  #Ensure connection is closed before trying to drop a database. 
  #As a connect call would have been made by call seeing connection in active
  disconnect!

  begin
    dropConn = IBM_DB.connect(connect_str, '', '')
  rescue StandardError => connect_err
    raise "Failed to connect to server due to: #{connect_err}"
  end

  if(IBM_DB.dropDB(dropConn,dbName))
    IBM_DB.close(dropConn)
    return true
  else
    error = IBM_DB.getErrormsg(dropConn, IBM_DB::DB_CONN)
    IBM_DB.close(dropConn)
    raise "Could not drop Database due to: #{error}"
  end
end

#empty_insert_statement_value(pkey) ⇒ Object 



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1264

def empty_insert_statement_value(pkey)
  "(#{pkey}) VALUES (DEFAULT)"
end

#exec_insert(sql, name, binds, pk, sequence_name) ⇒ Object 



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1407

def exec_insert(sql,name,binds,pk,sequence_name)
end

#exec_query(sql, name = 'SQL', binds = []) ⇒ Object

Executes sql statement in the context of this connection using binds as the bind substitutes. name is logged along with the executed sql statement.



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1376

def exec_query(sql, name = 'SQL', binds = [])
  begin
    param_array = binds.map do |column,value|
      quote_value_for_pstmt(value, column)
    end

    stmt = prepare(sql, name)

     if( stmt )
       if(execute_prepared_stmt(stmt, param_array))
         return stmt
       end
     else
       return false
     end
  ensure
    @offset = @limit = nil
  end
end

#execute(sql, name = nil) ⇒ Object

Executes and logs sql commands and returns a IBM_DB.Statement object.



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1398

def execute(sql, name=nil)
  # Logs and execute the sql instructions.
  # The +log+ method is defined in the parent class +AbstractAdapter+
	#sql='INSERT INTO ar_internal_metadata (key, value, created_at, updated_at) VALUES ('10', '10', '10', '10')
  log(sql , name) do
    @servertype.execute(sql, name)
  end
end

#execute_prepared_stmt(pstmt, param_array = nil) ⇒ Object

Praveen Executes the prepared statement ReturnsTrue on success and False on Failure



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1354

def execute_prepared_stmt(pstmt, param_array = nil)
  if !param_array.nil? && param_array.size < 1
    param_array = nil
  end

  if( !IBM_DB.execute(pstmt, param_array) )
    error_msg = IBM_DB.getErrormsg(pstmt, IBM_DB::DB_STMT)
    if !error_msg.empty?
      error_msg = "Statement execution failed: " + error_msg
    else
      error_msg = "Statement execution failed"
    end
    IBM_DB.free_stmt(pstmt) if pstmt
    raise StatementInvalid, error_msg
  else
    return true
  end
end

#extract_foreign_key_action(specifier) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 2353

def extract_foreign_key_action(specifier) # :nodoc:	      			
 case specifier
       when 0; :cascade
 when 1; :restrict
 when 2; :nullify
 when 3; :noaction		  
       end
end

#fetch_data(stmt) ⇒ Object

Calls the servertype select method to fetch the data



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1108

def fetch_data(stmt)
  if(stmt)
    begin
      return @servertype.select(stmt)
    rescue StandardError => fetch_error # Handle driver fetch errors
      error_msg = IBM_DB.getErrormsg(stmt, IBM_DB::DB_STMT )
      if error_msg && !error_msg.empty?
        raise StatementInvalid,"Failed to retrieve data: #{error_msg}"
      else
        error_msg = "An unexpected error occurred during data retrieval"
        error_msg = error_msg + ": #{fetch_error.message}" if !fetch_error.message.empty?
        raise error_msg
      end
    ensure
    # Ensures to free the resources associated with the statement
      IBM_DB.free_stmt(stmt) if stmt
    end
  end
end

#foreign_keys(table_name) ⇒ Object 



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 2302

def foreign_keys(table_name)	  
    #fetch the foreign keys of the table using function foreign_keys        
		#PKTABLE_NAME::  fk_row[2] Name of the table containing the primary key.
		#PKCOLUMN_NAME:: fk_row[3] Name of the column containing the primary key.		
		#FKTABLE_NAME::  fk_row[6] Name of the table containing the foreign key.
		#FKCOLUMN_NAME:: fk_row[7] Name of the column containing the foreign key.		
		#FK_NAME:: 		 fk_row[11] The name of the foreign key.
			
		table_name = @servertype.set_case(table_name.to_s)
		foreignKeys = []
    stmt = IBM_DB.foreignkeys( @connection, nil, 
                               @servertype.set_case(@schema), 
                               @servertype.set_case(table_name), "FK_TABLE")								
		
    if(stmt)
      begin
        while ( fk_row = IBM_DB.fetch_array(stmt) )			  
          options = {
column: fk_row[7],
name: fk_row[11],
primary_key: fk_row[3],
 }			  			  			  
 options[:on_update] = extract_foreign_key_action(fk_row[9])	
 options[:on_delete] = extract_foreign_key_action(fk_row[10])
 foreignKeys << ForeignKeyDefinition.new(fk_row[6], table_name, options) 
        end			

      rescue StandardError => fetch_error # Handle driver fetch errors
        error_msg = IBM_DB.getErrormsg(stmt, IBM_DB::DB_STMT )
        if error_msg && !error_msg.empty?
          raise "Failed to retrieve foreign key metadata during fetch: #{error_msg}"
        else
          error_msg = "An unexpected error occurred during retrieval of foreign key metadata"
          error_msg = error_msg + ": #{fetch_error.message}" if !fetch_error.message.empty?
          raise error_msg
        end
      ensure  # Free resources associated with the statement
        IBM_DB.free_stmt(stmt) if stmt
      end
    else  # Handle driver execution errors
      error_msg = IBM_DB.getErrormsg(@connection, IBM_DB::DB_CONN )
      if error_msg && !error_msg.empty?
        raise "Failed to retrieve foreign key metadata due to error: #{error_msg}"
      else
        raise StandardError.new('An unexpected error occurred during foreign key retrieval')		
      end		  
    end
#Returns the foreignKeys array
return foreignKeys
end

#get_limit_offset_clauses(limit, offset) ⇒ Object 



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1521

def get_limit_offset_clauses(limit,offset)

  if limit && limit == 0
    clauses = @servertype.get_limit_offset_clauses(limit,0)
  else
    clauses = @servertype.get_limit_offset_clauses(limit, offset)
  end
end

#indexes(table_name, name = nil) ⇒ Object

Returns an array of non-primary key indexes for a specified table name



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1992

def indexes(table_name, name = nil)
  # to_s required because +table_name+ may be a symbol.
  table_name = table_name.to_s
  # Checks if a blank table name has been given.
  # If so it returns an empty array of columns.
  return [] if table_name.strip.empty?

  indexes = []
  pk_index = nil
  index_schema = []
  
  #fetch the primary keys of the table using function primary_keys
  #TABLE_SCHEM:: pk_index[1]
  #TABLE_NAME:: pk_index[2]
  #COLUMN_NAME:: pk_index[3]
  #PK_NAME:: pk_index[5]
  stmt = IBM_DB.primary_keys( @connection, nil, 
                             @servertype.set_case(@schema), 
                             @servertype.set_case(table_name))
  if(stmt)
    begin
      while ( pk_index_row = IBM_DB.fetch_array(stmt) )
        if pk_index_row[5] 
          pk_index_name = pk_index_row[5].downcase
          pk_index_columns = [pk_index_row[3].downcase]           # COLUMN_NAME
          if pk_index 
            pk_index.columns = pk_index.columns + pk_index_columns
          else
            pk_index = IndexDefinition.new(table_name, pk_index_name, true, pk_index_columns)
          end
        end 
      end
    rescue StandardError => fetch_error # Handle driver fetch errors
      error_msg = IBM_DB.getErrormsg(stmt, IBM_DB::DB_STMT )
      if error_msg && !error_msg.empty?
        raise "Failed to retrieve primarykey metadata during fetch: #{error_msg}"
      else
        error_msg = "An unexpected error occurred during retrieval of primary key metadata"
        error_msg = error_msg + ": #{fetch_error.message}" if !fetch_error.message.empty?
        raise error_msg
      end
    ensure  # Free resources associated with the statement
      IBM_DB.free_stmt(stmt) if stmt
    end
  else  # Handle driver execution errors
    error_msg = IBM_DB.getErrormsg(@connection, IBM_DB::DB_CONN )
    if error_msg && !error_msg.empty?
      raise "Failed to retrieve primary key metadata due to error: #{error_msg}"
    else
      raise StandardError.new('An unexpected error occurred during primary key retrieval')
    end
  end

  # Query table statistics for all indexes on the table
  # "TABLE_NAME:   #{index_stats[2]}"
  # "NON_UNIQUE:   #{index_stats[3]}"
  # "INDEX_NAME:   #{index_stats[5]}"
  # "COLUMN_NAME:  #{index_stats[8]}"
  stmt = IBM_DB.statistics( @connection, nil, 
                            @servertype.set_case(@schema), 
                            @servertype.set_case(table_name), 1 )
  if(stmt)
    begin
      while ( index_stats = IBM_DB.fetch_array(stmt) )
        is_composite = false
        if index_stats[5]             # INDEX_NAME
          index_name = index_stats[5].downcase
          index_unique = (index_stats[3] == 0)
          index_columns = [index_stats[8].downcase]     # COLUMN_NAME
          index_qualifier = index_stats[4].downcase             #Index_Qualifier
          # Create an IndexDefinition object and add to the indexes array
          i = 0;
          indexes.each do |index|
            if index.name == index_name && index_schema[i] == index_qualifier
               #index.columns = index.columns + index_columns
               index.columns.concat index_columns
               is_composite = true
            end 
            i = i+1
          end
        
          unless is_composite 
            indexes << IndexDefinition.new(table_name, index_name, index_unique, index_columns)
            index_schema << index_qualifier
          end 
        end
      end
    rescue StandardError => fetch_error # Handle driver fetch errors
      error_msg = IBM_DB.getErrormsg(stmt, IBM_DB::DB_STMT )
      if error_msg && !error_msg.empty?
        raise "Failed to retrieve index metadata during fetch: #{error_msg}"
      else
        error_msg = "An unexpected error occurred during retrieval of index metadata"
        error_msg = error_msg + ": #{fetch_error.message}" if !fetch_error.message.empty?
        raise error_msg
      end
    ensure  # Free resources associated with the statement
      IBM_DB.free_stmt(stmt) if stmt
    end
  else  # Handle driver execution errors
    error_msg = IBM_DB.getErrormsg(@connection, IBM_DB::DB_CONN )
    if error_msg && !error_msg.empty?
      raise "Failed to retrieve index metadata due to error: #{error_msg}"
    else
      raise StandardError.new('An unexpected error occurred during index retrieval')
    end
  end
    
  # remove the primary key index entry.... should not be dumped by the dumper
    
  i = 0
  indexes.each do |index|
    if pk_index && index.columns == pk_index.columns
      indexes.delete_at(i)
    end
    i = i+1
  end 
  # Returns the indexes array
  return indexes
end

#insert(arel, name = nil, pk = nil, id_value = nil, sequence_name = nil, binds = []) ⇒ Object 



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1290

def insert(arel, name = nil, pk = nil, id_value = nil, sequence_name = nil, binds=[])
  if(@arelVersion <  6)
  sql, binds = [to_sql(arel), binds]
 else
  sql, binds = [to_sql(arel),binds] #sql_for_insert(to_sql(arel, binds), binds) #[to_sql(arel),binds]
 end

  #unless IBM_DBAdapter.respond_to?(:exec_insert)
  if binds.nil? || binds.empty?
    return insert_direct(sql, name, pk, id_value, sequence_name)
  end

  clear_query_cache if defined? clear_query_cache
    
		if stmt = exec_insert(sql, name, binds)
    begin
      @sql << sql
      return id_value || @servertype.last_generated_id(stmt)
    ensure
      IBM_DB.free_stmt(stmt) if stmt
    end
  end
end

#insert_direct(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil) ⇒ Object

Perform an insert and returns the last ID generated. This can be the ID passed to the method or the one auto-generated by the database, and retrieved by the last_generated_id method.



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1271

def insert_direct(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil)
  if @handle_lobs_triggered  #Ensure the array of sql is cleared if they have been handled in the callback
    @sql = []
    @handle_lobs_triggered = false
  end

  clear_query_cache if defined? clear_query_cache

  if stmt = execute(sql, name)
    begin
      @sql << sql
      return id_value || @servertype.last_generated_id(stmt)
      # Ensures to free the resources associated with the statement
    ensure
      IBM_DB.free_stmt(stmt) if stmt
    end
  end
end

#insert_fixture(fixture, table_name) ⇒ Object

inserts values from fixtures overridden to handle LOB’s fixture insertion, as, in normal inserts callbacks are triggered but during fixture insertion callbacks are not triggered hence only markers like @@@IBMBINARY@@@ will be inserted and are not updated to actual data



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1203

def insert_fixture(fixture, table_name)
  if(fixture.respond_to?(:keys))
    insert_query = "INSERT INTO #{quote_table_name(table_name)} ( #{fixture.keys.join(', ')})"
  else
    insert_query = "INSERT INTO #{quote_table_name(table_name)} ( #{fixture.key_list})"
  end

  insert_values = []
  params = []
  if @servertype.instance_of? IBM_IDS
    super
    return
  end
  column_list = columns(table_name)
  fixture.each do |item|
    col = nil
    column_list.each do |column|
      if column.name.downcase == item.at(0).downcase
        col= column
        break
      end
    end
		  
    if item.at(1).nil? || 
        item.at(1) == {} || 			  
			  (item.at(1) == '' && !(col.sql_type.to_s =~ /text|clob/i))
          params << 'NULL'
				
		  elsif (!col.nil? &&  (col.sql_type.to_s =~ /blob|binary|clob|text|xml/i)  )			
      #  Add a '?' for the parameter or a NULL if the value is nil or empty 
      # (except for a CLOB field where '' can be a value)
       insert_values << quote_value_for_pstmt(item.at(1))
       params << '?'
    else
      insert_values << quote_value_for_pstmt(item.at(1),col)
      params << '?'
    end 
  end
    
  insert_query << " VALUES ("+ params.join(',') + ")"
  unless stmt = IBM_DB.prepare(@connection, insert_query)
     error_msg = IBM_DB.getErrormsg( @connection, IBM_DB::DB_CONN )
     if error_msg && !error_msg.empty?
       raise "Failed to prepare statement for fixtures insert due to : #{error_msg}"
     else
       raise StandardError.new('An unexpected error occurred during preparing SQL for fixture insert')
     end
  end
    
  #log_query(insert_query,'fixture insert')
  log(insert_query,'fixture insert') do
    unless IBM_DB.execute(stmt, insert_values)
      error_msg = IBM_DB.getErrormsg(stmt, IBM_DB::DB_STMT )
      IBM_DB.free_stmt(stmt) if stmt
      raise "Failed to insert due to: #{error_msg}"
    else
      IBM_DB.free_stmt(stmt) if stmt
    end
  end
end

#log_query(sql, name) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 949

def log_query(sql, name) #:nodoc:
  # Used by handle_lobs
  log(sql,name){}
end

#native_database_types ⇒ Object

Returns a Hash of mappings from the abstract data types to the native database types



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1718

def native_database_types
  {
    :primary_key => { :name => @servertype.primary_key_definition(@start_id)},
    :string      => { :name => "varchar", :limit => 255 },
    :text        => { :name => "clob" },
    :integer     => { :name => "integer" },
    :float       => { :name => "float" },
    :datetime    => { :name => "timestamp" },
    :timestamp   => { :name => "timestamp" },		  
    :time        => { :name => "time" },
    :date        => { :name => "date" },
    :binary      => { :name => "blob" },

    # IBM data servers don't have a native boolean type.
    # A boolean can be represented  by a smallint,
    # adopting the convention that False is 0 and True is 1
    :boolean     => { :name => "smallint"},
    :xml         => { :name => "xml"},
    :decimal     => { :name => "decimal" },
    :rowid       => { :name => "rowid" }, # rowid is a supported datatype on z/OS and i/5
    :serial      => { :name => "serial" }, # rowid is a supported datatype on Informix Dynamic Server
    :char        => { :name => "char" },
    :double      => { :name => @servertype.get_double_mapping },
    :decfloat    => { :name => "decfloat"},
    :graphic     => { :name => "graphic", :limit => 1},
    :vargraphic  => { :name => "vargraphic", :limit => 1},
    :bigint      => { :name => "bigint"}
  }
end

#prepare(sql, name = nil) ⇒ Object

Praveen Prepares and logs sql commands and returns a IBM_DB.Statement object.



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1343

def prepare(sql,name = nil)
  # The +log+ method is defined in the parent class +AbstractAdapter+
  @prepared_sql = sql
  log(sql,name) do
    @servertype.prepare(sql, name)
  end
end

#prepared_insert(pstmt, param_array = nil, id_value = nil) ⇒ Object

Praveen Performs an insert using the prepared statement and returns the last ID generated. This can be the ID passed to the method or the one auto-generated by the database, and retrieved by the last_generated_id method.



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1318

def prepared_insert(pstmt, param_array = nil, id_value = nil)
  if @handle_lobs_triggered  #Ensure the array of sql is cleared if they have been handled in the callback
    @sql                   = []
    @sql_parameter_values  = []
    @handle_lobs_triggered = false
  end

  clear_query_cache if defined? clear_query_cache

  begin
    if execute_prepared_stmt(pstmt, param_array)
      @sql << @prepared_sql
      @sql_parameter_values << param_array
      return id_value || @servertype.last_generated_id(pstmt)
    end
  rescue StandardError => insert_err
    raise insert_err
  ensure
    IBM_DB.free_stmt(pstmt) if pstmt
  end
end

#prepared_select(sql_param_hash, name = nil) ⇒ Object

Returns an array of hashes with the column names as keys and column values as values. sql is the select query, and name is an optional description for logging



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1044

def prepared_select(sql_param_hash, name = nil)
  # Replaces {"= NULL" with " IS NULL"} OR {"IN (NULL)" with " IS NULL"}

  results = []
  # Invokes the method +prepare+ in order prepare the SQL
  # IBM_DB.Statement is returned from which the statement is executed and results fetched
  pstmt = prepare(sql_param_hash["sqlSegment"], name)
  if(execute_prepared_stmt(pstmt, sql_param_hash["paramArray"]))
    begin
      results = @servertype.select(pstmt)
    rescue StandardError => fetch_error # Handle driver fetch errors
      error_msg = IBM_DB.getErrormsg(pstmt, IBM_DB::DB_STMT )
      if error_msg && !error_msg.empty?
        raise StatementInvalid,"Failed to retrieve data: #{error_msg}"
      else
        error_msg = "An unexpected error occurred during data retrieval"
        error_msg = error_msg + ": #{fetch_error.message}" if !fetch_error.message.empty?
        raise error_msg
      end
    ensure
      # Ensures to free the resources associated with the statement
      IBM_DB.free_stmt(pstmt) if pstmt
    end
  end
  # The array of record hashes is returned
  results
end

#prepared_select_values(sql_param_hash, name = nil) ⇒ Object

Returns an array of hashes with the column names as keys and column values as values. sql is the select query, and name is an optional description for logging



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1075

def prepared_select_values(sql_param_hash, name = nil)
  # Replaces {"= NULL" with " IS NULL"} OR {"IN (NULL)" with " IS NULL"}
  results = []
  # Invokes the method +prepare+ in order prepare the SQL
  # IBM_DB.Statement is returned from which the statement is executed and results fetched
  pstmt = prepare(sql_param_hash["sqlSegment"], name)
  if(execute_prepared_stmt(pstmt, sql_param_hash["paramArray"]))
    begin
      results = @servertype.select_rows(sql_param_hash["sqlSegment"], name, pstmt, results)
      if results
        return results.map { |v| v[0] }
      else
        nil
      end
    rescue StandardError => fetch_error # Handle driver fetch errors
      error_msg = IBM_DB.getErrormsg(pstmt, IBM_DB::DB_STMT )
      if error_msg && !error_msg.empty?
        raise StatementInvalid,"Failed to retrieve data: #{error_msg}"
      else
        error_msg = "An unexpected error occurred during data retrieval"
        error_msg = error_msg + ": #{fetch_error.message}" if !fetch_error.message.empty?
        raise error_msg
      end
    ensure
      # Ensures to free the resources associated with the statement
      IBM_DB.free_stmt(pstmt) if pstmt
    end
  end
  # The array of record hashes is returned
  results
end

#prepared_update(pstmt, param_array = nil) ⇒ Object Also known as: prepared_delete

Praveen



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1431

def prepared_update(pstmt, param_array = nil )
  if @handle_lobs_triggered  #Ensure the array of sql is cleared if they have been handled in the callback
    @sql                   = []
    @sql_parameter_values  = []
    @handle_lobs_triggered = false
  end

  clear_query_cache if defined? clear_query_cache

  begin
    if execute_prepared_stmt(pstmt, param_array)
      @sql << @prepared_sql
      @sql_parameter_values << param_array
      # Retrieves the number of affected rows
      IBM_DB.num_rows(pstmt)
      # Ensures to free the resources associated with the statement
		  end
  rescue StandardError => updt_err
    raise updt_err
  ensure
    IBM_DB.free_stmt(pstmt) if pstmt
  end
end

#primary_key(table_name) ⇒ Object

Returns the primary key of the mentioned table



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1958

def primary_key(table_name)
  pk_name = nil
  stmt = IBM_DB.primary_keys( @connection, nil, 
                              @servertype.set_case(@schema), 
                              @servertype.set_case(table_name))
  if(stmt) 
    begin
      if ( pk_index_row = IBM_DB.fetch_array(stmt) )
        pk_name = pk_index_row[3].downcase
      end
    rescue StandardError => fetch_error # Handle driver fetch errors
      error_msg = IBM_DB.getErrormsg( stmt, IBM_DB::DB_STMT )
      if error_msg && !error_msg.empty?
        raise "Failed to retrieve primarykey metadata during fetch: #{error_msg}"
      else
        error_msg = "An unexpected error occurred during retrieval of primary key metadata"
        error_msg = error_msg + ": #{fetch_error.message}" if !fetch_error.message.empty?
        raise error_msg
      end
    ensure  # Free resources associated with the statement
      IBM_DB.free_stmt(stmt) if stmt
    end
  else
    error_msg = IBM_DB.getErrormsg( @connection, IBM_DB::DB_CONN )
    if error_msg && !error_msg.empty?
      raise "Failed to retrieve primary key metadata due to error: #{error_msg}"
    else
      raise StandardError.new('An unexpected error occurred during primary key retrieval')
    end
  end
  return pk_name
end

#quote_column_name(name) ⇒ Object 



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1708

def quote_column_name(name)
   @servertype.check_reserved_words(name)
end

#quote_value_for_pstmt(value, column = nil) ⇒ Object

def quoted_date(value) #:nodoc:

  if value.respond_to?(:usec)
    "#{super}.#{sprintf("%06d", value.usec)}"
  else
    super
  end
end



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1592

def quote_value_for_pstmt(value, column=nil)

  return value.quoted_id if value.respond_to?(:quoted_id)

  case value
    when String, ActiveSupport::Multibyte::Chars then
      value = value.to_s
			if column && column.sql_type.to_s =~ /int|serial|float/i
        value = column.sql_type.to_s =~ /int|serial/i ? value.to_i : value.to_f
        value
      else
        value
      end
    when NilClass                 then nil
    when TrueClass                then 1
    when FalseClass               then 0
    when Float, Fixnum, Bignum    then value
    # BigDecimals need to be output in a non-normalized form and quoted.
    when BigDecimal               then value.to_s('F')
    when Numeric, Symbol          then value.to_s
    else
      if value.acts_like?(:date) || value.acts_like?(:time)
        quoted_date(value)
      else
        value.to_yaml
      end
  end
end

#quoted_false ⇒ Object 



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1704

def quoted_false
  "0"
end

#quoted_true ⇒ Object

true is represented by a smallint 1, false by 0, as no native boolean type exists in DB2. Numerics are not quoted in DB2.



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1700

def quoted_true
  "1"
end

#reconnect! ⇒ Object

Closes the current connection and opens a new one



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1004

def reconnect!
  disconnect!
  connect
end

#remove_column(table_name, column_name) ⇒ Object

Removes the column from the table definition.

Examples
remove_column(:suppliers, :qualification)



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 2411

def remove_column(table_name, column_name)
  @servertype.remove_column(table_name, column_name)
end

#remove_index(table_name, options = {}) ⇒ Object

Remove the given index from the table.

Remove the suppliers_name_index in the suppliers table (legacy support, use the second or third forms).

remove_index :suppliers, :name

Remove the index named accounts_branch_id in the accounts table.

remove_index :accounts, :column => :branch_id

Remove the index named by_branch_party in the accounts table.

remove_index :accounts, :name => :by_branch_party

You can remove an index on multiple columns by specifying the first column.

add_index :accounts, [:username, :password]
remove_index :accounts, :username

Overriden to use the IBM data servers SQL syntax.



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 2473

def remove_index(table_name, options = {})
 execute("DROP INDEX #{index_name(table_name, options)}")
end

#rename_column(table_name, column_name, new_column_name) ⇒ Object

Renames a column.

Example
rename_column(:suppliers, :description, :name)



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 2404

def rename_column(table_name, column_name, new_column_name)
  @servertype.rename_column(table_name, column_name, new_column_name)
end

#rename_table(name, new_name) ⇒ Object

Renames a table.

Example

rename_table(‘octopuses’, ‘octopi’) Overriden to satisfy IBM data servers syntax



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 2392

def rename_table(name, new_name)
  # SQL rename table statement
  rename_table_sql = "RENAME TABLE #{name} TO #{new_name}"
  stmt = execute(rename_table_sql)
  # Ensures to free the resources associated with the statement
  ensure
    IBM_DB.free_stmt(stmt) if stmt
end

#rollback_db_transaction ⇒ Object

Rolls back the transaction and turns on auto-committing. Must be done if the transaction block raises an exception or returns false



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1514

def rollback_db_transaction
  # ROLLBACK the transaction
  IBM_DB.rollback(@connection) rescue nil
  # Turns on auto-committing
  IBM_DB.autocommit @connection, IBM_DB::SQL_AUTOCOMMIT_ON
end

#select(sql, name = nil, binds = []) ⇒ Object 



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1128

def select(sql, name = nil, binds = [])
  # Replaces {"= NULL" with " IS NULL"} OR {"IN (NULL)" with " IS NULL"
  sql.gsub( /(=\s*NULL|IN\s*\(NULL\))/i, " IS NULL" )

  results = []

  if(binds.nil? || binds.empty?)
    stmt = execute(sql, name)
  else
    stmt = exec_query(sql, name, binds)
  end

  cols = IBM_DB.resultCols(stmt)

  if( stmt ) 
    results = fetch_data(stmt)
  end

  if(@isAr3)
    return results
  else
    return ActiveRecord::Result.new(cols, results)
  end
end

#select_rows(sql, name = nil, binds = []) ⇒ Object

Returns an array of arrays containing the field values. This is an implementation for the abstract method sql is the select query and name is an optional description for logging



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1156

def select_rows(sql, name = nil,binds = [])
  # Replaces {"= NULL" with " IS NULL"} OR {"IN (NULL)" with " IS NULL"}
  sql.gsub( /(=\s*NULL|IN\s*\(NULL\))/i, " IS NULL" )
  
  results = []
  # Invokes the method +execute+ in order to log and execute the SQL
  # IBM_DB.Statement is returned from which results can be fetched
  if !binds.nil? && !binds.empty?
    param_array = binds.map do |column,value|
      quote_value_for_pstmt(value, column)
    end
    return prepared_select({"sqlSegment" => sql, "paramArray" => param_array})
  end

  stmt = execute(sql, name)
  if(stmt)
    begin
      results = @servertype.select_rows(sql, name, stmt, results)
    rescue StandardError => fetch_error  # Handle driver fetch errors
      error_msg = IBM_DB.getErrormsg(stmt, IBM_DB::DB_STMT )
      if error_msg && !error_msg.empty?
        raise StatementInvalid,"Failed to retrieve data: #{error_msg}"
      else
        error_msg = "An unexpected error occurred during data retrieval"
        error_msg = error_msg + ": #{fetch_error.message}" if !fetch_error.message.empty?
        raise error_msg
      end
    ensure
      # Ensures to free the resources associated with the statement
      IBM_DB.free_stmt(stmt) if stmt
    end
  end
  # The array of record hashes is returned
  results
end

#simplified_type(field_type) ⇒ Object

Mapping IBM data servers SQL datatypes to Ruby data types



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 2155

def simplified_type(field_type)
  case field_type
    # if +field_type+ contains 'for bit data' handle it as a binary
    when /for bit data/i
      :binary
    when /smallint/i
      :boolean
    when /int|serial/i
      :integer
    when /decimal|numeric|decfloat/i
      :decimal
    when /float|double|real/i
      :float
    when /timestamp|datetime/i
      :timestamp
    when /time/i
      :time
    when /date/i
      :date
    when /vargraphic/i
      :vargraphic
    when /graphic/i
      :graphic
    when /clob|text/i
      :text
    when /xml/i
      :xml
    when /blob|binary/i
      :binary
    when /char/i
      :string
    when /boolean/i
      :boolean
    when /rowid/i  # rowid is a supported datatype on z/OS and i/5
      :rowid
  end
end

#simplified_type2(field_type) ⇒ Object

Mapping IBM data servers SQL datatypes to Ruby data types



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 2115

def simplified_type2(field_type)
  case field_type
    # if +field_type+ contains 'for bit data' handle it as a binary
    when /for bit data/i
      "binary"
    when /smallint/i
      "boolean"
    when /int|serial/i
      "integer"
    when /decimal|numeric|decfloat/i
      "decimal"
    when /float|double|real/i
      "float"
    when /timestamp|datetime/i
      "timestamp"
    when /time/i
      "time"
    when /date/i
      "date"
    when /vargraphic/i
      "vargraphic"
    when /graphic/i
      "graphic"
    when /clob|text/i
      "text"
    when /xml/i
      "xml"
    when /blob|binary/i
      "binary"
    when /char/i
      "string"
    when /boolean/i
      "boolean"
    when /rowid/i  # rowid is a supported datatype on z/OS and i/5
      "rowid"
  end
end

#supports_datetime_with_precision? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 938

def supports_datetime_with_precision?
	true
end

#supports_ddl_transactions? ⇒ Boolean

This Adapter supports DDL transactions. This means CREATE TABLE and other DDL statements can be carried out as a transaction. That is the statements executed can be ROLLED BACK in case of any error during the process.

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 945

def supports_ddl_transactions?
  true
end

#supports_disable_referential_integrity? ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 2362

def supports_disable_referential_integrity? #:nodoc:
      true
end

#supports_foreign_keys? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 934

def supports_foreign_keys?
  true
end

#supports_migrations? ⇒ Boolean

This adapter supports migrations. Current limitations: rename_column is not currently supported by the IBM data servers remove_column is not currently supported by the DB2 for zOS data server Tables containing columns of XML data type do not support remove_column

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 930

def supports_migrations?
  true
end

#table_alias_length ⇒ Object

Returns the maximum length a table alias identifier can be. IBM data servers (cross-platform) table limit is 128 characters



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1868

def table_alias_length
  128
end

#tables(name = nil) ⇒ Object

Retrieves table’s metadata for a specified shema name



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1874

def tables(name = nil)
  # Initializes the tables array
  tables = []
  # Retrieve table's metadata through IBM_DB driver
  stmt = IBM_DB.tables(@connection, nil, 
                      @servertype.set_case(@schema))
  if(stmt)
    begin
      # Fetches all the records available
      while tab = IBM_DB.fetch_assoc(stmt)
        # Adds the lowercase table name to the array
        if(tab["table_type"]== 'TABLE')  #check, so that only tables are dumped,IBM_DB.tables also returns views,alias etc in the schema
          tables << tab["table_name"].downcase    
        end
      end
    rescue StandardError => fetch_error # Handle driver fetch errors
      error_msg = IBM_DB.getErrormsg(stmt, IBM_DB::DB_STMT )
      if error_msg && !error_msg.empty?
        raise "Failed to retrieve table metadata during fetch: #{error_msg}"
      else
        error_msg = "An unexpected error occurred during retrieval of table metadata"
        error_msg = error_msg + ": #{fetch_error.message}" if !fetch_error.message.empty?
        raise error_msg
      end
    ensure
      IBM_DB.free_stmt(stmt)  if stmt # Free resources associated with the statement
    end
  else # Handle driver execution errors
    error_msg = IBM_DB.getErrormsg(@connection, IBM_DB::DB_CONN )
    if error_msg && !error_msg.empty?
      raise "Failed to retrieve tables metadata due to error: #{error_msg}"
    else
      raise StandardError.new('An unexpected error occurred during retrieval of table metadata')
    end
  end
  # Returns the tables array
  return tables
end

#to_sql(arel, binds = []) ⇒ Object 



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 915

def to_sql(arel, binds = [])
			if arel.respond_to?(:ast)
 visitor.accept(arel.ast) do
quote(*binds.shift.reverse)
 end
			else
 arel
			end
end

#type_to_sql(type, limit = nil, precision = nil, scale = nil) ⇒ Object

IBM data servers do not support limits on certain data types (unlike MySQL) Limit is supported for the decimal, numeric, varchar, clob, blob, graphic, vargraphic data types.



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1815

def type_to_sql(type, limit=nil, precision=nil, scale=nil )
  if type.to_sym == :decimal
    if limit.class == Hash
      if limit.has_key?("precision".to_sym)
        precision = limit[:precision]
      end
    end
    if limit.class == Hash
      if limit.has_key?("scale".to_sym)
        scale = limit[:scale]
      end
    end
    sql_segment = native_database_types[type.to_sym][:name].to_s
    if !precision.nil? && !scale.nil?
      sql_segment << "(#{precision},#{scale})"
      return sql_segment
    elsif scale.nil? && !precision.nil?
      sql_segment << "(#{precision})"
    else
      return sql_segment
    end
  end

  if type.to_sym == :decfloat
    sql_segment = native_database_types[type.to_sym][:name].to_s
    sql_segment << "(#{precision})" if !precision.nil?
    return sql_segment
  end

  if limit.class == Hash
    return super if limit.has_key?("limit".to_sym).nil?
  else
    return super if limit.nil?
  end

  # strip off limits on data types not supporting them
  if @servertype.limit_not_supported_types.include? type.to_sym
    return native_database_types[type.to_sym][:name].to_s
  elsif type.to_sym == :boolean
    return "smallint"
  else
    return super(type)
  end

end

#update(arel, name = nil, binds = []) ⇒ Object Also known as: delete 



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1459

def update(arel, name = nil, binds = [])
  if(@arelVersion <  6 )
  sql = to_sql(arel)
else
  sql = to_sql(arel,binds)
end

  # Make sure the WHERE clause handles NULL's correctly
  sqlarray = sql.split(/\s*WHERE\s*/)
  size = sqlarray.size
  if size > 1
    sql = sqlarray[0] + " WHERE "
    if size > 2
      1.upto size-2 do |index|
        sqlarray[index].gsub!( /(=\s*NULL|IN\s*\(NULL\))/i, " IS NULL" ) unless sqlarray[index].nil?
        sql = sql + sqlarray[index] + " WHERE "
      end
    end
    sqlarray[size-1].gsub!( /(=\s*NULL|IN\s*\(NULL\))/i, " IS NULL" ) unless sqlarray[size-1].nil?
    sql = sql + sqlarray[size-1]
  end

  clear_query_cache if defined? clear_query_cache

  if binds.nil? || binds.empty?
    update_direct(sql, name)
  else
    begin
      if stmt = exec_query(sql,name,binds)
        IBM_DB.num_rows(stmt)
      end
    ensure
      IBM_DB.free_stmt(stmt) if(stmt)
    end
  end
end

#update_direct(sql, name = nil) ⇒ Object

Executes an “UPDATE” SQL statement



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1411

def update_direct(sql, name = nil)
  if @handle_lobs_triggered  #Ensure the array of sql is cleared if they have been handled in the callback
    @sql = []
    @handle_lobs_triggered = false
  end

  # Logs and execute the given sql query.
  if stmt = execute(sql, name)
    begin
      @sql << sql
      # Retrieves the number of affected rows
      IBM_DB.num_rows(stmt)
      # Ensures to free the resources associated with the statement
    ensure
      IBM_DB.free_stmt(stmt) if stmt
    end
  end
end

#valid_type?(type) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1808

def valid_type?(type)		
  #!native_database_types[type].nil?
		native_database_types[type].nil?
end

#views ⇒ Object

Retrieves views’s metadata for a specified shema name



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# File 'lib/active_record/connection_adapters/ibm_db_adapter.rb', line 1917

def views
  # Initializes the tables array
  tables = []
  # Retrieve view's metadata through IBM_DB driver
  stmt = IBM_DB.tables(@connection, nil, 
                      @servertype.set_case(@schema))
  if(stmt)
    begin
      # Fetches all the records available
      while tab = IBM_DB.fetch_assoc(stmt)
        # Adds the lowercase view's name to the array
        if(tab["table_type"]== 'V')  #check, so that only views are dumped,IBM_DB.tables also returns tables,alias etc in the schema
          tables << tab["table_name"].downcase    
        end
      end
    rescue StandardError => fetch_error # Handle driver fetch errors
      error_msg = IBM_DB.getErrormsg(stmt, IBM_DB::DB_STMT )
      if error_msg && !error_msg.empty?
        raise "Failed to retrieve views metadata during fetch: #{error_msg}"
      else
        error_msg = "An unexpected error occurred during retrieval of views metadata"
        error_msg = error_msg + ": #{fetch_error.message}" if !fetch_error.message.empty?
        raise error_msg
      end
    ensure
      IBM_DB.free_stmt(stmt)  if stmt # Free resources associated with the statement
    end
  else # Handle driver execution errors
    error_msg = IBM_DB.getErrormsg(@connection, IBM_DB::DB_CONN )
    if error_msg && !error_msg.empty?
      raise "Failed to retrieve tables metadata due to error: #{error_msg}"
    else
      raise StandardError.new('An unexpected error occurred during retrieval of views metadata')
    end
  end
  # Returns the tables array
  return tables
end