Module: Sequel::DB2::DatasetMethods

Includes:
EmulateOffsetWithRowNumber
Included in:
Dataset, IBMDB::Dataset, JDBC::DB2::Dataset, ODBC::DB2::Dataset
Defined in:
lib/sequel/adapters/shared/db2.rb

Constant Summary collapse

BITWISE_METHOD_MAP = 
{:& =>:BITAND, :| => :BITOR, :^ => :BITXOR, :'B~'=>:BITNOT}
BOOL_TRUE = 
'1'.freeze
BOOL_FALSE = 
'0'.freeze

Instance Method Summary collapse

Methods included from EmulateOffsetWithRowNumber

#select_sql

Instance Method Details

#cast_sql(expr, type) ⇒ Object

DB2 casts strings using RTRIM and CHAR instead of VARCHAR.



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# File 'lib/sequel/adapters/shared/db2.rb', line 183

def cast_sql(expr, type)
  type == String ?  "RTRIM(CHAR(#{literal(expr)}))" : super
end

#complex_expression_sql(op, args) ⇒ Object

Handle DB2 specific LIKE and bitwise operator support, and emulate the extract method, which DB2 doesn’t natively support.



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# File 'lib/sequel/adapters/shared/db2.rb', line 189

def complex_expression_sql(op, args)
  case op
  when :ILIKE
    super(:LIKE, [SQL::Function.new(:upper, args.at(0)), SQL::Function.new(:upper, args.at(1)) ])
  when :"NOT ILIKE"
    super(:"NOT LIKE", [SQL::Function.new(:upper, args.at(0)), SQL::Function.new(:upper, args.at(1)) ])
  when :&, :|, :^
    # works with db2 v9.5 and after
    op = BITWISE_METHOD_MAP[op]
    complex_expression_arg_pairs(args){|a, b| literal(SQL::Function.new(op, a, b))}
  when :<<
    complex_expression_arg_pairs(args){|a, b| "(#{literal(a)} * POWER(2, #{literal(b)}))"}
  when :>>
    complex_expression_arg_pairs(args){|a, b| "(#{literal(a)} / POWER(2, #{literal(b)}))"}
  when :'B~'
    literal(SQL::Function.new(:BITNOT, *args))
  when :extract
    "#{args.at(0)}(#{literal(args.at(1))})"
  else
    super
  end
end

#supports_is_true? ⇒ Boolean

DB2 does not support IS TRUE.

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/db2.rb', line 213

def supports_is_true?
  false
end

#supports_multiple_column_in? ⇒ Boolean

DB2 does not support multiple columns in IN.

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/db2.rb', line 218

def supports_multiple_column_in?
  false
end

#supports_select_all_and_column? ⇒ Boolean

DB2 only allows * in SELECT if it is the only thing being selected.

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/db2.rb', line 223

def supports_select_all_and_column?
  false
end

#supports_timestamp_usecs? ⇒ Boolean

DB2 does not support fractional seconds in timestamps.

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/db2.rb', line 228

def supports_timestamp_usecs?
  false
end

#supports_where_true? ⇒ Boolean

DB2 does not support WHERE 1.

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/db2.rb', line 238

def supports_where_true?
  false
end

#supports_window_functions? ⇒ Boolean

DB2 supports window functions

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/db2.rb', line 233

def supports_window_functions?
  true
end