DB2 always uses :db2 as it’s database type
# File lib/sequel/adapters/shared/db2.rb, line 25 def database_type :db2 end
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 31 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
# File lib/sequel/adapters/shared/db2.rb, line 37 def freeze db2_version offset_strategy super end
Use SYSCAT.INDEXES to get the indexes for the table
# File lib/sequel/adapters/shared/db2.rb, line 82 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
# File lib/sequel/adapters/shared/db2.rb, line 95 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
Use SYSIBM.SYSCOLUMNS to get the information on the tables.
# File lib/sequel/adapters/shared/db2.rb, line 44 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
DB2 supports transaction isolation levels.
# File lib/sequel/adapters/shared/db2.rb, line 107 def supports_transaction_isolation_levels? true end
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.
# File lib/sequel/adapters/shared/db2.rb, line 114 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
Use SYSCAT.TABLES to get the tables for the database
# File lib/sequel/adapters/shared/db2.rb, line 68 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
Use SYSCAT.TABLES to get the views for the database
# File lib/sequel/adapters/shared/db2.rb, line 75 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