Module: Sequel::MSSQL::DatasetMethods

Included in:
ADO::MSSQL::Dataset, JDBC::MSSQL::Dataset, ODBC::MSSQL::Dataset, TinyTDS::Dataset
Defined in:
lib/sequel/adapters/shared/mssql.rb

Constant Summary collapse

BOOL_TRUE = 
'1'.freeze
BOOL_FALSE = 
'0'.freeze
COMMA_SEPARATOR = 
', '.freeze
DELETE_CLAUSE_METHODS = 
Dataset.clause_methods(:delete, %w'with from output from2 where')
INSERT_CLAUSE_METHODS = 
Dataset.clause_methods(:insert, %w'with into columns output values')
SELECT_CLAUSE_METHODS = 
Dataset.clause_methods(:select, %w'with distinct limit columns into from lock join where group having order compounds')
UPDATE_CLAUSE_METHODS = 
Dataset.clause_methods(:update, %w'with table set output from where')
NOLOCK = 
' WITH (NOLOCK)'.freeze
UPDLOCK = 
' WITH (UPDLOCK)'.freeze
WILDCARD = 
LiteralString.new('*').freeze
CONSTANT_MAP = 
{:CURRENT_DATE=>'CAST(CURRENT_TIMESTAMP AS DATE)'.freeze, :CURRENT_TIME=>'CAST(CURRENT_TIMESTAMP AS TIME)'.freeze}

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#mssql_unicode_strings ⇒ Object

Allow overriding of the mssql_unicode_strings option at the dataset level.



226
227
228
 
# File 'lib/sequel/adapters/shared/mssql.rb', line 226

def mssql_unicode_strings
  @mssql_unicode_strings
end

Instance Method Details

#complex_expression_sql(op, args) ⇒ Object

MSSQL uses + for string concatenation, and LIKE is case insensitive by default.



235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
 
# File 'lib/sequel/adapters/shared/mssql.rb', line 235

def complex_expression_sql(op, args)
  case op
  when :'||'
    super(:+, args)
  when :ILIKE
    super(:LIKE, args)
  when :"NOT ILIKE"
    super(:"NOT LIKE", args)
  when :<<
    "(#{literal(args[0])} * POWER(2, #{literal(args[1])}))"
  when :>>
    "(#{literal(args[0])} / POWER(2, #{literal(args[1])}))"
  else
    super(op, args)
  end
end

#constant_sql(constant) ⇒ Object

MSSQL doesn’t support the SQL standard CURRENT_DATE or CURRENT_TIME



253
254
255
 
# File 'lib/sequel/adapters/shared/mssql.rb', line 253

def constant_sql(constant)
  CONSTANT_MAP[constant] || super
end

#disable_insert_output ⇒ Object

Disable the use of INSERT OUTPUT



258
259
260
 
# File 'lib/sequel/adapters/shared/mssql.rb', line 258

def disable_insert_output
  clone(:disable_insert_output=>true)
end

#disable_insert_output! ⇒ Object

Disable the use of INSERT OUTPUT, modifying the receiver



263
264
265
 
# File 'lib/sequel/adapters/shared/mssql.rb', line 263

def disable_insert_output!
  mutation_method(:disable_insert_output)
end

#fetch_rows(sql, &block) ⇒ Object

When returning all rows, if an offset is used, delete the row_number column before yielding the row.



269
270
271
 
# File 'lib/sequel/adapters/shared/mssql.rb', line 269

def fetch_rows(sql, &block)
  @opts[:offset] ? super(sql){|r| r.delete(row_number_column); yield r} : super(sql, &block)
end

#full_text_search(cols, terms, opts = {}) ⇒ Object

MSSQL uses the CONTAINS keyword for full text search



274
275
276
 
# File 'lib/sequel/adapters/shared/mssql.rb', line 274

def full_text_search(cols, terms, opts = {})
  filter("CONTAINS (#{literal(cols)}, #{literal(terms)})")
end

#initialize(db, opts = {}) ⇒ Object

Copy the mssql_unicode_strings option from the db object.



229
230
231
232
 
# File 'lib/sequel/adapters/shared/mssql.rb', line 229

def initialize(db, opts={})
  super
  @mssql_unicode_strings = db.mssql_unicode_strings
end

#insert_select(*values) ⇒ Object

Use the OUTPUT clause to get the value of all columns for the newly inserted record.



279
280
281
282
 
# File 'lib/sequel/adapters/shared/mssql.rb', line 279

def insert_select(*values)
  return unless supports_output_clause?
  naked.clone(default_server_opts(:sql=>output(nil, [:inserted.*]).insert_sql(*values))).single_record unless opts[:disable_insert_output]
end

#into(table) ⇒ Object

Specify a table for a SELECT … INTO query.



285
286
287
 
# File 'lib/sequel/adapters/shared/mssql.rb', line 285

def into(table)
  clone(:into => table)
end

#join_table(type, table, expr = nil, table_alias = {}, &block) ⇒ Object

SQL Server does not support CTEs on subqueries, so move any CTEs on joined datasets to the top level. The user is responsible for resolving any name clashes this may cause.



292
293
294
295
 
# File 'lib/sequel/adapters/shared/mssql.rb', line 292

def join_table(type, table, expr=nil, table_alias={}, &block)
  return super unless Dataset === table && table.opts[:with]
  clone(:with => (opts[:with] || []) + table.opts[:with]).join_table(type, table.clone(:with => nil), expr, table_alias, &block)
end

#multi_insert_sql(columns, values) ⇒ Object

MSSQL uses a UNION ALL statement to insert multiple values at once.



298
299
300
 
# File 'lib/sequel/adapters/shared/mssql.rb', line 298

def multi_insert_sql(columns, values)
  [insert_sql(columns, LiteralString.new(values.map {|r| "SELECT #{expression_list(r)}" }.join(" UNION ALL ")))]
end

#nolock ⇒ Object

Allows you to do a dirty read of uncommitted data using WITH (NOLOCK).



303
304
305
 
# File 'lib/sequel/adapters/shared/mssql.rb', line 303

def nolock
  lock_style(:dirty)
end

#output(into, values) ⇒ Object

Include an OUTPUT clause in the eventual INSERT, UPDATE, or DELETE query.

The first argument is the table to output into, and the second argument is either an Array of column values to select, or a Hash which maps output column names to selected values, in the style of #insert or #update.

Output into a returned result set is not currently supported.

Examples:

dataset.output(:output_table, [:deleted__id, :deleted__name])
dataset.output(:output_table, :id => :inserted__id, :name => :inserted__name)

Raises:



319
320
321
322
323
324
325
326
327
328
329
330
 
# File 'lib/sequel/adapters/shared/mssql.rb', line 319

def output(into, values)
  raise(Error, "SQL Server versions 2000 and earlier do not support the OUTPUT clause") unless supports_output_clause?
  output = {}
  case values
    when Hash
      output[:column_list], output[:select_list] = values.keys, values.values
    when Array
      output[:select_list] = values
  end
  output[:into] = into
  clone({:output => output})
end

#output!(into, values) ⇒ Object

An output method that modifies the receiver.



333
334
335
 
# File 'lib/sequel/adapters/shared/mssql.rb', line 333

def output!(into, values)
  mutation_method(:output, into, values)
end

#quoted_identifier(name) ⇒ Object

MSSQL uses [] to quote identifiers



338
339
340
 
# File 'lib/sequel/adapters/shared/mssql.rb', line 338

def quoted_identifier(name)
  "[#{name}]"
end

#select_sql ⇒ Object

MSSQL Requires the use of the ROW_NUMBER window function to emulate an offset. This implementation requires MSSQL 2005 or greater (offset can’t be emulated well in MSSQL 2000).

The implementation is ugly, cloning the current dataset and modifying the clone to add a ROW_NUMBER window function (and some other things), then using the modified clone in a subselect which is selected from.

If offset is used, an order must be provided, because the use of ROW_NUMBER requires an order.

Raises:



352
353
354
355
356
357
358
359
360
361
362
363
 
# File 'lib/sequel/adapters/shared/mssql.rb', line 352

def select_sql
  return super unless o = @opts[:offset]
  raise(Error, 'MSSQL requires an order be provided if using an offset') unless order = @opts[:order]
  dsa1 = dataset_alias(1)
  rn = row_number_column
  subselect_sql(unlimited.
    unordered.
    select_append{ROW_NUMBER(:over, :order=>order){}.as(rn)}.
    from_self(:alias=>dsa1).
    limit(@opts[:limit]).
    where(SQL::Identifier.new(rn) > o))
end

#server_version ⇒ Object

The version of the database server.



366
367
368
 
# File 'lib/sequel/adapters/shared/mssql.rb', line 366

def server_version
  db.server_version(@opts[:server])
end

#supports_intersect_except? ⇒ Boolean

MSSQL 2005+ supports INTERSECT and EXCEPT

Returns:

  • (Boolean) 


371
372
373
 
# File 'lib/sequel/adapters/shared/mssql.rb', line 371

def supports_intersect_except?
  is_2005_or_later?
end

#supports_is_true? ⇒ Boolean

MSSQL does not support IS TRUE

Returns:

  • (Boolean) 


376
377
378
 
# File 'lib/sequel/adapters/shared/mssql.rb', line 376

def supports_is_true?
  false
end

#supports_join_using? ⇒ Boolean

MSSQL doesn’t support JOIN USING

Returns:

  • (Boolean) 


381
382
383
 
# File 'lib/sequel/adapters/shared/mssql.rb', line 381

def supports_join_using?
  false
end

#supports_modifying_joins? ⇒ Boolean

MSSQL 2005+ supports modifying joined datasets

Returns:

  • (Boolean) 


386
387
388
 
# File 'lib/sequel/adapters/shared/mssql.rb', line 386

def supports_modifying_joins?
  is_2005_or_later?
end

#supports_multiple_column_in? ⇒ Boolean

MSSQL does not support multiple columns for the IN/NOT IN operators

Returns:

  • (Boolean) 


391
392
393
 
# File 'lib/sequel/adapters/shared/mssql.rb', line 391

def supports_multiple_column_in?
  false
end

#supports_output_clause? ⇒ Boolean

MSSQL 2005+ supports the output clause.

Returns:

  • (Boolean) 


396
397
398
 
# File 'lib/sequel/adapters/shared/mssql.rb', line 396

def supports_output_clause?
  is_2005_or_later?
end

#supports_window_functions? ⇒ Boolean

MSSQL 2005+ supports window functions

Returns:

  • (Boolean) 


401
402
403
 
# File 'lib/sequel/adapters/shared/mssql.rb', line 401

def supports_window_functions?
  true
end