Module: Sequel::MSSQL::DatasetMethods

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

Constant Summary collapse

CONSTANT_MAP = 
{:CURRENT_DATE=>'CAST(CURRENT_TIMESTAMP AS DATE)'.freeze, :CURRENT_TIME=>'CAST(CURRENT_TIMESTAMP AS TIME)'.freeze}.freeze
EXTRACT_MAP = 
{:year=>"yy", :month=>"m", :day=>"d", :hour=>"hh", :minute=>"n", :second=>"s"}.freeze
LIMIT_ALL = 
Object.new.freeze

Instance Method Summary collapse

Methods included from EmulateOffsetWithRowNumber

#empty?

Instance Method Details

#complex_expression_sql_append(sql, op, args) ⇒ Object 


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# File 'lib/sequel/adapters/shared/mssql.rb', line 523

def complex_expression_sql_append(sql, op, args)
  case op
  when :'||'
    super(sql, :+, args)
  when :LIKE, :"NOT LIKE"
    super(sql, op, args.map{|a| Sequel.lit(["(", " COLLATE Latin1_General_CS_AS)"], a)})
  when :ILIKE, :"NOT ILIKE"
    super(sql, (op == :ILIKE ? :LIKE : :"NOT LIKE"), args.map{|a| Sequel.lit(["(", " COLLATE Latin1_General_CI_AS)"], a)})
  when :<<, :>>
    complex_expression_emulate_append(sql, op, args)
  when :extract
    part = args[0]
    raise(Sequel::Error, "unsupported extract argument: #{part.inspect}") unless format = EXTRACT_MAP[part]
    if part == :second
      expr = args[1]
      sql << "CAST((datepart(" << format.to_s << ', '
      literal_append(sql, expr)
      sql << ') + datepart(ns, '
      literal_append(sql, expr)
      sql << ")/1000000000.0) AS double precision)"
    else
      sql << "datepart(" << format.to_s << ', '
      literal_append(sql, args[1])
      sql << ')'
    end
  else
    super
  end
end

#constant_sql_append(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 554

def constant_sql_append(sql, constant)
  if c = CONSTANT_MAP[constant]
    sql << c
  else
    super
  end
end

#cross_apply(table) ⇒ Object

Uses CROSS APPLY to join the given table into the current dataset.


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# File 'lib/sequel/adapters/shared/mssql.rb', line 563

def cross_apply(table)
  join_table(:cross_apply, table)
end

#disable_insert_output ⇒ Object

Disable the use of INSERT OUTPUT


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# File 'lib/sequel/adapters/shared/mssql.rb', line 568

def disable_insert_output
  clone(:disable_insert_output=>true)
end

#escape_like(string) ⇒ Object

MSSQL treats [] as a metacharacter in LIKE expresions.


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# File 'lib/sequel/adapters/shared/mssql.rb', line 573

def escape_like(string)
  string.gsub(/[\\%_\[\]]/){|m| "\\#{m}"}
end

#full_text_search(cols, terms, opts = OPTS) ⇒ Object

MSSQL uses the CONTAINS keyword for full text search


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# File 'lib/sequel/adapters/shared/mssql.rb', line 578

def full_text_search(cols, terms, opts = OPTS)
  terms = "\"#{terms.join('" OR "')}\"" if terms.is_a?(Array)
  where(Sequel.lit("CONTAINS (?, ?)", cols, 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 584

def insert_select(*values)
  return unless supports_insert_select?
  with_sql_first(insert_select_sql(*values))
end

#insert_select_sql(*values) ⇒ Object

Add OUTPUT clause unless there is already an existing output clause, then return the SQL to insert.


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# File 'lib/sequel/adapters/shared/mssql.rb', line 591

def insert_select_sql(*values)
  ds = (opts[:output] || opts[:returning]) ? self : output(nil, [SQL::ColumnAll.new(:inserted)])
  ds.insert_sql(*values)
end

#into(table) ⇒ Object

Specify a table for a SELECT … INTO query.


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# File 'lib/sequel/adapters/shared/mssql.rb', line 597

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

#mssql_unicode_strings ⇒ Object

Use the database's mssql_unicode_strings setting if the dataset hasn't overridden it.


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# File 'lib/sequel/adapters/shared/mssql.rb', line 514

def mssql_unicode_strings
  opts.has_key?(:mssql_unicode_strings) ? opts[:mssql_unicode_strings] : db.mssql_unicode_strings
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 602

def nolock
  lock_style(:dirty)
end

#outer_apply(table) ⇒ Object

Uses OUTER APPLY to join the given table into the current dataset.


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# File 'lib/sequel/adapters/shared/mssql.rb', line 607

def outer_apply(table)
  join_table(:outer_apply, table)
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, [Sequel[:deleted][:id], Sequel[:deleted][:name]])
dataset.output(:output_table, id: Sequel[:inserted][:id], name: Sequel[:inserted][:name])

Raises:


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# File 'lib/sequel/adapters/shared/mssql.rb', line 623

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

#quoted_identifier_append(sql, name) ⇒ Object

MSSQL uses [] to quote identifiers.


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# File 'lib/sequel/adapters/shared/mssql.rb', line 637

def quoted_identifier_append(sql, name)
  sql << '[' << name.to_s.gsub(/\]/, ']]') << ']'
end

#returning(*values) ⇒ Object

Emulate RETURNING using the output clause. This only handles values that are simple column references.


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# File 'lib/sequel/adapters/shared/mssql.rb', line 642

def returning(*values)
  values = values.map do |v|
    unless r = unqualified_column_for(v)
      raise(Error, "cannot emulate RETURNING via OUTPUT for value: #{v.inspect}")
    end
    r
  end
  clone(:returning=>values)
end

#select_sql ⇒ Object

On MSSQL 2012+ add a default order to the current dataset if an offset is used. The default offset emulation using a subquery would be used in the unordered case by default, and that also adds a default order, so it's better to just avoid the subquery.


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# File 'lib/sequel/adapters/shared/mssql.rb', line 656

def select_sql
  if @opts[:offset] && !@opts[:order] && is_2012_or_later?
    order(1).select_sql
  else
    super
  end
end

#server_version ⇒ Object

The version of the database server.


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# File 'lib/sequel/adapters/shared/mssql.rb', line 665

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

#supports_cte?(type = :select) ⇒ Boolean

Returns:

  • (Boolean) 

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# File 'lib/sequel/adapters/shared/mssql.rb', line 669

def supports_cte?(type=:select)
  is_2005_or_later?
end

#supports_group_cube? ⇒ Boolean

MSSQL 2005+ supports GROUP BY CUBE.

Returns:

  • (Boolean) 

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# File 'lib/sequel/adapters/shared/mssql.rb', line 674

def supports_group_cube?
  is_2005_or_later?
end

#supports_group_rollup? ⇒ Boolean

MSSQL 2005+ supports GROUP BY ROLLUP

Returns:

  • (Boolean) 

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# File 'lib/sequel/adapters/shared/mssql.rb', line 679

def supports_group_rollup?
  is_2005_or_later?
end

#supports_grouping_sets? ⇒ Boolean

MSSQL 2008+ supports GROUPING SETS

Returns:

  • (Boolean) 

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# File 'lib/sequel/adapters/shared/mssql.rb', line 684

def supports_grouping_sets?
  is_2008_or_later?
end

#supports_insert_select? ⇒ Boolean

MSSQL supports insert_select via the OUTPUT clause.

Returns:

  • (Boolean) 

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# File 'lib/sequel/adapters/shared/mssql.rb', line 689

def supports_insert_select?
  supports_output_clause? && !opts[:disable_insert_output]
end

#supports_intersect_except? ⇒ Boolean

MSSQL 2005+ supports INTERSECT and EXCEPT

Returns:

  • (Boolean) 

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# File 'lib/sequel/adapters/shared/mssql.rb', line 694

def supports_intersect_except?
  is_2005_or_later?
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 699

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 704

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 709

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) 

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# File 'lib/sequel/adapters/shared/mssql.rb', line 714

def supports_multiple_column_in?
  false
end

#supports_offsets_in_correlated_subqueries? ⇒ Boolean

MSSQL 2012+ supports offsets in correlated subqueries.

Returns:

  • (Boolean) 

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# File 'lib/sequel/adapters/shared/mssql.rb', line 719

def supports_offsets_in_correlated_subqueries?
  is_2012_or_later?
end

#supports_output_clause? ⇒ Boolean

MSSQL 2005+ supports the OUTPUT clause.

Returns:

  • (Boolean) 

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# File 'lib/sequel/adapters/shared/mssql.rb', line 724

def supports_output_clause?
  is_2005_or_later?
end

#supports_returning?(type) ⇒ Boolean

MSSQL 2005+ can emulate RETURNING via the OUTPUT clause.

Returns:

  • (Boolean) 

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# File 'lib/sequel/adapters/shared/mssql.rb', line 729

def supports_returning?(type)
  supports_insert_select?
end

#supports_skip_locked? ⇒ Boolean

MSSQL uses READPAST to skip locked rows.

Returns:

  • (Boolean) 

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# File 'lib/sequel/adapters/shared/mssql.rb', line 734

def supports_skip_locked?
  true
end

#supports_where_true? ⇒ Boolean

MSSQL cannot use WHERE 1.

Returns:

  • (Boolean) 

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# File 'lib/sequel/adapters/shared/mssql.rb', line 744

def supports_where_true?
  false
end

#supports_window_functions? ⇒ Boolean

MSSQL 2005+ supports window functions

Returns:

  • (Boolean) 

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# File 'lib/sequel/adapters/shared/mssql.rb', line 739

def supports_window_functions?
  true
end

#with_mssql_unicode_strings(v) ⇒ Object

Return a cloned dataset with the mssql_unicode_strings option set.


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# File 'lib/sequel/adapters/shared/mssql.rb', line 519

def with_mssql_unicode_strings(v)
  clone(:mssql_unicode_strings=>v)
end