Module: Sequel::DB2::DatabaseMethods

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 Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#use_clob_as_blob ⇒ Object 



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# File 'lib/sequel/adapters/shared/db2.rb', line 35

def use_clob_as_blob
  v = @use_clob_as_blob
  v.nil? ? Sequel::DB2.instance_variable_get(:@use_clob_as_blob) : v
end

Instance Method Details

#database_type ⇒ Object

DB2 always uses :db2 as it's database type



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# File 'lib/sequel/adapters/shared/db2.rb', line 41

def database_type
  :db2
end

#db2_version ⇒ Object 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 47

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

#freeze ⇒ Object 



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# File 'lib/sequel/adapters/shared/db2.rb', line 53

def freeze
  db2_version
  offset_strategy
  super
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 98

def indexes(table, opts = OPTS)
  m = output_identifier_meth
  indexes = {}
  metadata_dataset.
   from(Sequel[: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

#offset_strategy ⇒ Object 



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# File 'lib/sequel/adapters/shared/db2.rb', line 111

def offset_strategy
  return @offset_strategy if defined?(@offset_strategy)

  @offset_strategy = case strategy = opts[:offset_strategy].to_s
  when "limit_offset", "offset_fetch"
    opts[:offset_strategy] = strategy.to_sym
  else
    opts[:offset_strategy] = :emulate
  end
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 60

def schema_parse_table(table, opts = OPTS)
  m = output_identifier_meth(opts[:dataset])
  im = input_identifier_meth(opts[:dataset])
  metadata_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] =~ /\A(VAR)?CHAR\z/
        column[:db_type] << "(#{column[:length]})"
      end
      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 123

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 130

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

#tables ⇒ Object

Use SYSCAT.TABLES to get the tables for the database



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# File 'lib/sequel/adapters/shared/db2.rb', line 84

def tables
  metadata_dataset.
    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

#views ⇒ Object

Use SYSCAT.TABLES to get the views for the database



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# File 'lib/sequel/adapters/shared/db2.rb', line 91

def views
  metadata_dataset.
    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