module Sequel::DB2::DatabaseMethods

Constants

AUTOINCREMENT
DATABASE_ERROR_REGEXPS
NOT_NULL
NULL

Public Instance Methods

database_type() click to toggle source

DB2 always uses :db2 as it's database type

# File lib/sequel/adapters/shared/db2.rb, line 20
def database_type
  :db2
end
db2_version() click to toggle source

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

# File lib/sequel/adapters/shared/db2.rb, line 26
def db2_version
  return @db2_version if @db2_version
  @db2_version = metadata_dataset.with_sql("select service_level from sysibmadm.env_inst_info").first[:service_level]
end
Also aliased as: server_version
indexes(table, opts = OPTS) click to toggle source

Use SYSCAT.INDEXES to get the indexes for the table

# File lib/sequel/adapters/shared/db2.rb, line 68
def indexes(table, opts = OPTS)
  m = output_identifier_meth
  indexes = {}
  metadata_dataset.
   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) click to toggle source

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

# 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])
  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]  == "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
server_version()
Alias for: db2_version
supports_transaction_isolation_levels?() click to toggle source

DB2 supports transaction isolation levels.

# File lib/sequel/adapters/shared/db2.rb, line 82
def supports_transaction_isolation_levels?
  true
end
tables() click to toggle source

Use SYSCAT.TABLES to get the tables for the database

# File lib/sequel/adapters/shared/db2.rb, line 54
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() click to toggle source

Use SYSCAT.TABLES to get the views for the database

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

Private Instance Methods

alter_table_sql(table, op) click to toggle source

Handle DB2 specific alter table operations.

Calls superclass method
# File lib/sequel/adapters/shared/db2.rb, line 89
def alter_table_sql(table, op)
  case op[:op]
  when :add_column
    if op[:primary_key] && op[:auto_increment] && op[:type] == Integer
      [
      "ALTER TABLE #{quote_schema_table(table)} ADD #{column_definition_sql(op.merge(:auto_increment=>false, :primary_key=>false, :default=>0, :null=>false))}",
      "ALTER TABLE #{quote_schema_table(table)} ALTER COLUMN #{literal(op[:name])} DROP DEFAULT",
      "ALTER TABLE #{quote_schema_table(table)} ALTER COLUMN #{literal(op[:name])} SET #{AUTOINCREMENT}"
      ]
    else
      "ALTER TABLE #{quote_schema_table(table)} ADD #{column_definition_sql(op)}"
    end
  when :drop_column
    "ALTER TABLE #{quote_schema_table(table)} DROP #{column_definition_sql(op)}"
  when :rename_column       # renaming is only possible after db2 v9.7
    "ALTER TABLE #{quote_schema_table(table)} RENAME COLUMN #{quote_identifier(op[:name])} TO #{quote_identifier(op[:new_name])}"
  when :set_column_type
    "ALTER TABLE #{quote_schema_table(table)} ALTER COLUMN #{quote_identifier(op[:name])} SET DATA TYPE #{type_literal(op)}"
  when :set_column_default
    "ALTER TABLE #{quote_schema_table(table)} ALTER COLUMN #{quote_identifier(op[:name])} SET DEFAULT #{literal(op[:default])}"
  when :add_constraint
    if op[:type] == :unique
      sqls = op[:columns].map{|c| ["ALTER TABLE #{quote_schema_table(table)} ALTER COLUMN #{quote_identifier(c)} SET NOT NULL", reorg_sql(table)]}
      sqls << super
      sqls.flatten
    else
      super
    end
  else
    super
  end
end
auto_increment_sql() click to toggle source

DB2 uses an identity column for autoincrement.

# File lib/sequel/adapters/shared/db2.rb, line 123
def auto_increment_sql
  AUTOINCREMENT
end
column_definition_null_sql(sql, column) click to toggle source

Add null/not null SQL fragment to column creation SQL.

# File lib/sequel/adapters/shared/db2.rb, line 128
def column_definition_null_sql(sql, column)
  null = column.fetch(:null, column[:allow_null]) 
  null = false  if column[:primary_key]

  sql << NOT_NULL if null == false
  sql << NULL if null == true
end
column_list_sql(g) click to toggle source

Supply columns with NOT NULL if they are part of a composite primary key or unique constraint

Calls superclass method
# File lib/sequel/adapters/shared/db2.rb, line 138
def column_list_sql(g)
  ks = []
  g.constraints.each{|c| ks = c[:columns] if [:primary_key, :unique].include?(c[:type])} 
  g.columns.each{|c| c[:null] = false if ks.include?(c[:name]) }
  super
end
create_table_as(name, sql, options) click to toggle source

Insert data from the current table into the new table after creating the table, since it is not possible to do it in one step.

Calls superclass method
# File lib/sequel/adapters/shared/db2.rb, line 147
def create_table_as(name, sql, options)
  super
  from(name).insert(sql.is_a?(Dataset) ? sql : dataset.with_sql(sql))
end
create_table_as_sql(name, sql, options) click to toggle source

DB2 requires parens around the SELECT, and DEFINITION ONLY at the end.

# File lib/sequel/adapters/shared/db2.rb, line 153
def create_table_as_sql(name, sql, options)
  "#{create_table_prefix_sql(name, options)} AS (#{sql}) DEFINITION ONLY"
end
create_table_prefix_sql(name, options) click to toggle source

Here we use DGTT which has most backward compatibility, which uses DECLARE instead of CREATE. CGTT can only be used after version 9.7. www.ibm.com/developerworks/data/library/techarticle/dm-0912globaltemptable/

Calls superclass method
# File lib/sequel/adapters/shared/db2.rb, line 160
def create_table_prefix_sql(name, options)
  if options[:temp]
    "DECLARE GLOBAL TEMPORARY TABLE #{quote_identifier(name)}"
  else
    super
  end
end
database_error_regexps() click to toggle source
# File lib/sequel/adapters/shared/db2.rb, line 175
def database_error_regexps
  DATABASE_ERROR_REGEXPS
end
quote_identifiers_default() click to toggle source

DB2 has issues with quoted identifiers, so turn off database quoting by default.

# File lib/sequel/adapters/shared/db2.rb, line 181
def quote_identifiers_default
  false
end
rename_table_sql(name, new_name) click to toggle source

DB2 uses RENAME TABLE to rename tables.

# File lib/sequel/adapters/shared/db2.rb, line 186
def rename_table_sql(name, new_name)
  "RENAME TABLE #{quote_schema_table(name)} TO #{quote_schema_table(new_name)}"
end
reorg(table) click to toggle source

Run the REORG TABLE command for the table, necessary when the table has been altered.

# File lib/sequel/adapters/shared/db2.rb, line 192
def reorg(table)
  synchronize(opts[:server]){|c| c.execute(reorg_sql(table))}
end
reorg_sql(table) click to toggle source

The SQL to use for REORGing a table.

# File lib/sequel/adapters/shared/db2.rb, line 197
def reorg_sql(table)
  "CALL ADMIN_CMD(#{literal("REORG TABLE #{table}")})"
end
schema_column_type(db_type) click to toggle source

Treat clob as blob if use_clob_as_blob is true

Calls superclass method
# File lib/sequel/adapters/shared/db2.rb, line 202
def schema_column_type(db_type)
  (::Sequel::DB2::use_clob_as_blob && db_type.downcase == 'clob') ? :blob : super
end
set_transaction_isolation_sql(level) click to toggle source

SQL to set the transaction isolation level

# File lib/sequel/adapters/shared/db2.rb, line 207
def set_transaction_isolation_sql(level)
  "SET CURRENT ISOLATION #{Database::TRANSACTION_ISOLATION_LEVELS[level]}"
end
type_literal_generic_falseclass(column)
type_literal_generic_file(column) click to toggle source

We uses the clob type by default for Files. Note: if user select to use blob, then insert statement should use use this for blob value:

cast(X'fffefdfcfbfa' as blob(2G))
# File lib/sequel/adapters/shared/db2.rb, line 215
def type_literal_generic_file(column)
  ::Sequel::DB2::use_clob_as_blob ? :clob : :blob
end
type_literal_generic_trueclass(column) click to toggle source

DB2 uses smallint to store booleans.

# File lib/sequel/adapters/shared/db2.rb, line 220
def type_literal_generic_trueclass(column)
  :smallint
end
uses_clob_for_text?() click to toggle source

DB2 uses clob for text types.

# File lib/sequel/adapters/shared/db2.rb, line 226
def uses_clob_for_text?
  true
end
view_with_check_option_support() click to toggle source

DB2 supports views with check option.

# File lib/sequel/adapters/shared/db2.rb, line 231
def view_with_check_option_support
  :local
end