Module: Sequel::MSSQL::DatasetMethods

Included in:
ADO::MSSQL::Dataset, JDBC::MSSQL::Dataset, ODBC::MSSQL::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 limit distinct 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 Method Summary collapse

Instance Method Details

#complex_expression_sql(op, args) ⇒ Object

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



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# File 'lib/sequel/adapters/shared/mssql.rb', line 201

def complex_expression_sql(op, args)
  case op
  when :'||'
    super(:+, args)
  when :ILIKE
    super(:LIKE, args)
  when :"NOT ILIKE"
    super(:"NOT LIKE", args)
  else
    super(op, args)
  end
end

#constant_sql(constant) ⇒ Object

MSSQL doesn’t support the SQL standard CURRENT_DATE or CURRENT_TIME



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# File 'lib/sequel/adapters/shared/mssql.rb', line 215

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

#disable_insert_output ⇒ Object

Disable the use of INSERT OUTPUT



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# File 'lib/sequel/adapters/shared/mssql.rb', line 220

def disable_insert_output
  clone(:disable_insert_output=>true)
end

#disable_insert_output! ⇒ Object

Disable the use of INSERT OUTPUT, modifying the receiver



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# File 'lib/sequel/adapters/shared/mssql.rb', line 225

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.



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

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



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# File 'lib/sequel/adapters/shared/mssql.rb', line 236

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

#insert_select(*values) ⇒ Object

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



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# File 'lib/sequel/adapters/shared/mssql.rb', line 241

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.



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# File 'lib/sequel/adapters/shared/mssql.rb', line 247

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

#multi_insert_sql(columns, values) ⇒ Object

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



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# File 'lib/sequel/adapters/shared/mssql.rb', line 252

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).



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# File 'lib/sequel/adapters/shared/mssql.rb', line 257

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:



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# File 'lib/sequel/adapters/shared/mssql.rb', line 273

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.



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

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

#quoted_identifier(name) ⇒ Object

MSSQL uses [] to quote identifiers



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

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:



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# File 'lib/sequel/adapters/shared/mssql.rb', line 306

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.



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# File 'lib/sequel/adapters/shared/mssql.rb', line 320

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

#supports_intersect_except? ⇒ Boolean

Microsoft SQL Server does not support INTERSECT or EXCEPT

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/mssql.rb', line 325

def supports_intersect_except?
  false
end

#supports_is_true? ⇒ Boolean

MSSQL does not support IS TRUE

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/mssql.rb', line 330

def supports_is_true?
  false
end

#supports_join_using? ⇒ Boolean

MSSQL doesn’t support JOIN USING

Returns:

  • (Boolean) 


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

def supports_join_using?
  false
end

#supports_modifying_joins? ⇒ Boolean

MSSQL 2005+ supports modifying joined datasets

Returns:

  • (Boolean) 


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

def supports_modifying_joins?
  true
end

#supports_multiple_column_in? ⇒ Boolean

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

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/mssql.rb', line 345

def supports_multiple_column_in?
  false
end

#supports_output_clause? ⇒ Boolean

Only 2005+ supports the output clause.

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/mssql.rb', line 350

def supports_output_clause?
  server_version >= 9000000
end

#supports_window_functions? ⇒ Boolean

MSSQL 2005+ supports window functions

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/mssql.rb', line 355

def supports_window_functions?
  true
end