module Sequel::DB2::DatasetMethods

Constants

BITWISE_METHOD_MAP

Public Instance Methods

cast_sql_append(sql, expr, type) click to toggle source

DB2 casts strings using RTRIM and CHAR instead of VARCHAR.

Calls superclass method
    # File lib/sequel/adapters/shared/db2.rb
294 def cast_sql_append(sql, expr, type)
295   if(type == String)
296     sql << "RTRIM(CHAR("
297     literal_append(sql, expr)
298     sql << "))"
299   else
300     super
301   end
302 end
complex_expression_sql_append(sql, op, args) click to toggle source
Calls superclass method
    # File lib/sequel/adapters/shared/db2.rb
304 def complex_expression_sql_append(sql, op, args)
305   case op
306   when :&, :|, :^, :%, :<<, :>>
307     complex_expression_emulate_append(sql, op, args)
308   when :'B~'
309     literal_append(sql, SQL::Function.new(:BITNOT, *args))
310   when :extract
311     sql << args[0].to_s
312     sql << '('
313     literal_append(sql, args[1])
314     sql << ')'
315   else
316     super
317   end
318 end
quote_identifiers?() click to toggle source
    # File lib/sequel/adapters/shared/db2.rb
320 def quote_identifiers?
321   @opts.fetch(:quote_identifiers, false)
322 end
supports_cte?(type=:select) click to toggle source
    # File lib/sequel/adapters/shared/db2.rb
324 def supports_cte?(type=:select)
325   type == :select
326 end
supports_group_cube?() click to toggle source

DB2 supports GROUP BY CUBE

    # File lib/sequel/adapters/shared/db2.rb
329 def supports_group_cube?
330   true
331 end
supports_group_rollup?() click to toggle source

DB2 supports GROUP BY ROLLUP

    # File lib/sequel/adapters/shared/db2.rb
334 def supports_group_rollup?
335   true
336 end
supports_grouping_sets?() click to toggle source

DB2 supports GROUPING SETS

    # File lib/sequel/adapters/shared/db2.rb
339 def supports_grouping_sets?
340   true
341 end
supports_is_true?() click to toggle source

DB2 does not support IS TRUE.

    # File lib/sequel/adapters/shared/db2.rb
344 def supports_is_true?
345   false
346 end
supports_lateral_subqueries?() click to toggle source

DB2 supports lateral subqueries

    # File lib/sequel/adapters/shared/db2.rb
349 def supports_lateral_subqueries?
350   true
351 end
supports_merge?() click to toggle source

DB2 supports MERGE

    # File lib/sequel/adapters/shared/db2.rb
354 def supports_merge?
355   true
356 end
supports_multiple_column_in?() click to toggle source

DB2 does not support multiple columns in IN.

    # File lib/sequel/adapters/shared/db2.rb
359 def supports_multiple_column_in?
360   false
361 end
supports_select_all_and_column?() click to toggle source

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

    # File lib/sequel/adapters/shared/db2.rb
364 def supports_select_all_and_column?
365   false
366 end
supports_where_true?() click to toggle source

DB2 does not support WHERE 1.

    # File lib/sequel/adapters/shared/db2.rb
374 def supports_where_true?
375   false
376 end
supports_window_functions?() click to toggle source

DB2 supports window functions

    # File lib/sequel/adapters/shared/db2.rb
369 def supports_window_functions?
370   true
371 end

Private Instance Methods

_merge_when_conditions_sql(sql, data) click to toggle source

Normalize conditions for MERGE WHEN.

    # File lib/sequel/adapters/shared/db2.rb
381 def _merge_when_conditions_sql(sql, data)
382   if data.has_key?(:conditions)
383     sql << " AND "
384     literal_append(sql, _normalize_merge_when_conditions(data[:conditions]))
385   end
386 end
_normalize_merge_when_conditions(conditions) click to toggle source

Handle nil, false, and true MERGE WHEN conditions to avoid non-boolean type error.

    # File lib/sequel/adapters/shared/db2.rb
390 def _normalize_merge_when_conditions(conditions)
391   case conditions
392   when nil, false
393     {1=>0}
394   when true
395     {1=>1}
396   when Sequel::SQL::DelayedEvaluation
397     Sequel.delay{_normalize_merge_when_conditions(conditions.call(self))}
398   else
399     conditions
400   end
401 end
_truncate_sql(table) click to toggle source
    # File lib/sequel/adapters/shared/db2.rb
497 def _truncate_sql(table)
498   # "TRUNCATE #{table} IMMEDIATE" is only for newer version of db2, so we
499   # use the following one
500   "ALTER TABLE #{quote_schema_table(table)} ACTIVATE NOT LOGGED INITIALLY WITH EMPTY TABLE"
501 end
empty_from_sql() click to toggle source
    # File lib/sequel/adapters/shared/db2.rb
403 def empty_from_sql
404   ' FROM "SYSIBM"."SYSDUMMY1"'
405 end
emulate_offset_with_row_number?() click to toggle source

Emulate offset with row number by default, and also when the limit_offset strategy is used without a limit, as DB2 doesn’t support that syntax with no limit.

    # File lib/sequel/adapters/shared/db2.rb
410 def emulate_offset_with_row_number?
411   super && (db.offset_strategy == :emulate || (db.offset_strategy == :limit_offset && !@opts[:limit]))
412 end
insert_supports_empty_values?() click to toggle source

DB2 needs the standard workaround to insert all default values into a table with more than one column.

    # File lib/sequel/adapters/shared/db2.rb
416 def insert_supports_empty_values?
417   false
418 end
literal_blob_append(sql, v) click to toggle source

DB2 uses a literal hexidecimal number for blob strings

Calls superclass method
    # File lib/sequel/adapters/shared/db2.rb
436 def literal_blob_append(sql, v)
437   if db.use_clob_as_blob
438     super
439   else
440     sql << "BLOB(X'" << v.unpack("H*").first << "')"
441   end
442 end
literal_false() click to toggle source

Use 0 for false on DB2

    # File lib/sequel/adapters/shared/db2.rb
421 def literal_false
422   '0'
423 end
literal_sqltime(v) click to toggle source

DB2 doesn’t support fractional seconds in times, only fractional seconds in timestamps.

    # File lib/sequel/adapters/shared/db2.rb
426 def literal_sqltime(v)
427   v.strftime("'%H:%M:%S'")
428 end
literal_true() click to toggle source

Use 1 for true on DB2

    # File lib/sequel/adapters/shared/db2.rb
431 def literal_true
432   '1'
433 end
multi_insert_sql_strategy() click to toggle source

DB2 can insert multiple rows using a UNION

    # File lib/sequel/adapters/shared/db2.rb
445 def multi_insert_sql_strategy
446   :union
447 end
native_function_name(emulated_function) click to toggle source

Emulate the char_length function with length

Calls superclass method
    # File lib/sequel/adapters/shared/db2.rb
450 def native_function_name(emulated_function)
451   if emulated_function == :char_length
452     'length'
453   else
454     super
455   end
456 end
require_offset_order?() click to toggle source

DB2 does not require that ROW_NUMBER be ordered.

    # File lib/sequel/adapters/shared/db2.rb
459 def require_offset_order?
460   false
461 end
requires_emulating_nulls_first?() click to toggle source

At least some versions of DB do not support NULLS FIRST/LAST.

    # File lib/sequel/adapters/shared/db2.rb
464 def requires_emulating_nulls_first?
465   true
466 end
select_limit_sql(sql) click to toggle source

Modify the sql to limit the number of rows returned. Uses :offset_strategy Database option to determine how to format the limit and offset.

Calls superclass method
    # File lib/sequel/adapters/shared/db2.rb
471 def select_limit_sql(sql)
472   strategy = db.offset_strategy
473   return super if strategy == :limit_offset
474 
475   if strategy == :offset_fetch && (o = @opts[:offset]) 
476     sql << " OFFSET "
477     literal_append(sql, o)
478     sql << " ROWS"
479   end
480 
481   if l = @opts[:limit]
482     if l == 1
483       sql << " FETCH FIRST ROW ONLY"
484     else
485       sql << " FETCH FIRST "
486       literal_append(sql, l)
487       sql << " ROWS ONLY"
488     end
489   end
490 end
supports_quoted_function_names?() click to toggle source

DB2 supports quoted function names.

    # File lib/sequel/adapters/shared/db2.rb
493 def supports_quoted_function_names?
494   true
495 end