Module: Sequel::DB2::DatabaseMethods

Extended by:
Sequel::Database::ResetIdentifierMangling
Included in:
IBMDB::Database, JDBC::DB2::DatabaseMethods
Defined in:
lib/sequel/adapters/shared/db2.rb

Constant Summary collapse

AUTOINCREMENT =
'GENERATED ALWAYS AS IDENTITY'.freeze
NOT_NULL =
' NOT NULL'.freeze
NULL =
''.freeze

Instance Method Summary collapse

Methods included from Sequel::Database::ResetIdentifierMangling

extended

Instance Method Details

#database_typeObject

DB2 always uses :db2 as it's database type


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# File 'lib/sequel/adapters/shared/db2.rb', line 20

def database_type
  :db2
end

#db2_versionObject Also known as: server_version

Return the database version as a string. Don't rely on this, it may return an integer in the future.


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# File 'lib/sequel/adapters/shared/db2.rb', line 26

def db2_version
  return @db2_version if @db2_version
  @db2_version = .with_sql("select service_level from sysibmadm.env_inst_info").first[:service_level]
end

#indexes(table, opts = OPTS) ⇒ Object

Use SYSCAT.INDEXES to get the indexes for the table


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# File 'lib/sequel/adapters/shared/db2.rb', line 68

def indexes(table, opts = OPTS)
  m = output_identifier_meth
  indexes = {}
  .
   from(:syscat__indexes).
   select(:indname, :uniquerule, :colnames).
   where(:tabname=>input_identifier_meth.call(table), :system_required=>0).
   each do |r|
    indexes[m.call(r[:indname])] = {:unique=>(r[:uniquerule]=='U'), :columns=>r[:colnames][1..-1].split('+').map{|v| m.call(v)}}
  end
  indexes
end

#schema_parse_table(table, opts = OPTS) ⇒ Object

Use SYSIBM.SYSCOLUMNS to get the information on the tables.


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# File 'lib/sequel/adapters/shared/db2.rb', line 33

def schema_parse_table(table, opts = OPTS)
  m = output_identifier_meth(opts[:dataset])
  im = input_identifier_meth(opts[:dataset])
  .with_sql("SELECT * FROM SYSIBM.SYSCOLUMNS WHERE TBNAME = #{literal(im.call(table))} ORDER BY COLNO").
    collect do |column| 
      column[:db_type]     = column.delete(:typename)
      if column[:db_type]  == "DECIMAL"
        column[:db_type] << "(#{column[:longlength]},#{column[:scale]})"
      end
      column[:allow_null]  = column.delete(:nulls) == 'Y'
      identity = column.delete(:identity) == 'Y'
      if column[:primary_key] = identity || !column[:keyseq].nil?
        column[:auto_increment] = identity
      end
      column[:type]        = schema_column_type(column[:db_type])
      column[:max_length]  = column[:longlength] if column[:type] == :string
      [ m.call(column.delete(:name)), column]
    end
end

#supports_transaction_isolation_levels?Boolean

DB2 supports transaction isolation levels.

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/db2.rb', line 82

def supports_transaction_isolation_levels?
  true
end

#table_exists?(name) ⇒ Boolean

On DB2, a table might need to be REORGed if you are testing existence of it. This REORGs automatically if the database raises a specific error that indicates it should be REORGed.

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/db2.rb', line 89

def table_exists?(name)
  v ||= false # only retry once
  sch, table_name = schema_and_table(name)
  name = SQL::QualifiedIdentifier.new(sch, table_name) if sch
  from(name).first
  true
rescue DatabaseError => e
  if e.to_s =~ /Operation not allowed for reason code "7" on table/ && v == false
    # table probably needs reorg
    reorg(name)
    v = true
    retry 
  end
  false
end

#tablesObject

Use SYSCAT.TABLES to get the tables for the database


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# File 'lib/sequel/adapters/shared/db2.rb', line 54

def tables
  .
    with_sql("SELECT TABNAME FROM SYSCAT.TABLES WHERE TYPE='T' AND OWNER = #{literal(input_identifier_meth.call(opts[:user]))}").
    all.map{|h| output_identifier_meth.call(h[:tabname]) }
end

#viewsObject

Use SYSCAT.TABLES to get the views for the database


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# File 'lib/sequel/adapters/shared/db2.rb', line 61

def views
  .
    with_sql("SELECT TABNAME FROM SYSCAT.TABLES WHERE TYPE='V' AND OWNER = #{literal(input_identifier_meth.call(opts[:user]))}").
    all.map{|h| output_identifier_meth.call(h[:tabname]) }
end