Module: Sequel::SQLite::DatasetMethods

Includes:
Dataset::Replace, UnmodifiedIdentifiers::DatasetMethods
Included in:
Amalgalite::Dataset, Dataset
Defined in:
lib/sequel/adapters/shared/sqlite.rb

Constant Summary collapse

INSERT_CONFLICT_RESOLUTIONS =

The allowed values for insert_conflict

%w'ROLLBACK ABORT FAIL IGNORE REPLACE'.each(&:freeze).freeze
CONSTANT_MAP = 
{:CURRENT_DATE=>"date(CURRENT_TIMESTAMP, 'localtime')".freeze, :CURRENT_TIMESTAMP=>"datetime(CURRENT_TIMESTAMP, 'localtime')".freeze, :CURRENT_TIME=>"time(CURRENT_TIMESTAMP, 'localtime')".freeze}.freeze
EXTRACT_MAP = 
{:year=>"'%Y'", :month=>"'%m'", :day=>"'%d'", :hour=>"'%H'", :minute=>"'%M'", :second=>"'%f'"}.freeze

Instance Method Summary collapse

Instance Method Details

#cast_sql_append(sql, expr, type) ⇒ Object 



596
597
598
599
600
601
602
603
604
605
606
607
608
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 596

def cast_sql_append(sql, expr, type)
  if type == Time or type == DateTime
    sql << "datetime("
    literal_append(sql, expr)
    sql << ')'
  elsif type == Date
    sql << "date("
    literal_append(sql, expr)
    sql << ')'
  else
    super
  end
end

#complex_expression_sql_append(sql, op, args) ⇒ Object

SQLite doesn’t support a NOT LIKE b, you need to use NOT (a LIKE b). It doesn’t support xor, power, or the extract function natively, so those have to be emulated.



612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 612

def complex_expression_sql_append(sql, op, args)
  case op
  when :"NOT LIKE", :"NOT ILIKE"
    sql << 'NOT '
    complex_expression_sql_append(sql, (op == :"NOT ILIKE" ? :ILIKE : :LIKE), args)
  when :^
    complex_expression_arg_pairs_append(sql, args){|a, b| Sequel.lit(["((~(", " & ", ")) & (", " | ", "))"], a, b, a, b)}
  when :**
    unless (exp = args[1]).is_a?(Integer)
      raise(Sequel::Error, "can only emulate exponentiation on SQLite if exponent is an integer, given #{exp.inspect}")
    end
    case exp
    when 0
      sql << '1'
    else
      sql << '('
      arg = args[0]
      if exp < 0
        invert = true
        exp = exp.abs
        sql << '(1.0 / ('
      end
      (exp - 1).times do 
        literal_append(sql, arg)
        sql << " * "
      end
      literal_append(sql, arg)
      sql << ')'
      if invert
        sql << "))"
      end
    end
  when :extract
    part = args[0]
    raise(Sequel::Error, "unsupported extract argument: #{part.inspect}") unless format = EXTRACT_MAP[part]
    sql << "CAST(strftime(" << format << ', '
    literal_append(sql, args[1])
    sql << ') AS ' << (part == :second ? 'NUMERIC' : 'INTEGER') << ')'
  else
    super
  end
end

#constant_sql_append(sql, constant) ⇒ Object

SQLite has CURRENT_TIMESTAMP and related constants in UTC instead of in localtime, so convert those constants to local time.



657
658
659
660
661
662
663
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 657

def constant_sql_append(sql, constant)
  if (c = CONSTANT_MAP[constant]) && !db.current_timestamp_utc
    sql << c
  else
    super
  end
end

#delete(&block) ⇒ Object

SQLite performs a TRUNCATE style DELETE if no filter is specified. Since we want to always return the count of records, add a condition that is always true and then delete.



668
669
670
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 668

def delete(&block)
  @opts[:where] ? super : where(1=>1).delete(&block)
end

#empty? ⇒ Boolean

Always return false when using VALUES

Returns:

  • (Boolean) 


673
674
675
676
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 673

def empty?
  return false if @opts[:values]
  super
end

#explain(opts = nil) ⇒ Object

Return an array of strings specifying a query explanation for a SELECT of the current dataset. Currently, the options are ignored, but it accepts options to be compatible with other adapters.



681
682
683
684
685
686
687
688
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 681

def explain(opts=nil)
  # Load the PrettyTable class, needed for explain output
  Sequel.extension(:_pretty_table) unless defined?(Sequel::PrettyTable)

  ds = db.send(:metadata_dataset).clone(:sql=>"EXPLAIN #{select_sql}")
  rows = ds.all
  Sequel::PrettyTable.string(rows, ds.columns)
end

#having(*cond) ⇒ Object

HAVING requires GROUP BY on SQLite

Raises:

  • (InvalidOperation) 


691
692
693
694
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 691

def having(*cond)
  raise(InvalidOperation, "Can only specify a HAVING clause on a grouped dataset") if !@opts[:group] && db.sqlite_version < 33900
  super
end

#insert_conflict(opts = :ignore) ⇒ Object

Handle uniqueness violations when inserting, by using a specified resolution algorithm. With no options, uses INSERT OR REPLACE. SQLite supports the following conflict resolution algoriths: ROLLBACK, ABORT, FAIL, IGNORE and REPLACE.

On SQLite 3.24.0+, you can pass a hash to use an ON CONFLICT clause. With out :update option, uses ON CONFLICT DO NOTHING. Options:

:conflict_where

The index filter, when using a partial index to determine uniqueness.

:target

The column name or expression to handle uniqueness violations on.

:update

A hash of columns and values to set. Uses ON CONFLICT DO UPDATE.

:update_where

A WHERE condition to use for the update.

Examples:

DB[:table].insert_conflict.insert(a: 1, b: 2)
# INSERT OR IGNORE INTO TABLE (a, b) VALUES (1, 2)

DB[:table].insert_conflict(:replace).insert(a: 1, b: 2)
# INSERT OR REPLACE INTO TABLE (a, b) VALUES (1, 2)

DB[:table].insert_conflict({}).insert(a: 1, b: 2)
# INSERT INTO TABLE (a, b) VALUES (1, 2)
# ON CONFLICT DO NOTHING

DB[:table].insert_conflict(target: :a).insert(a: 1, b: 2)
# INSERT INTO TABLE (a, b) VALUES (1, 2)
# ON CONFLICT (a) DO NOTHING

DB[:table].insert_conflict(target: :a, conflict_where: {c: true}).insert(a: 1, b: 2)
# INSERT INTO TABLE (a, b) VALUES (1, 2)
# ON CONFLICT (a) WHERE (c IS TRUE) DO NOTHING

DB[:table].insert_conflict(target: :a, update: {b: Sequel[:excluded][:b]}).insert(a: 1, b: 2)
# INSERT INTO TABLE (a, b) VALUES (1, 2)
# ON CONFLICT (a) DO UPDATE SET b = excluded.b

DB[:table].insert_conflict(target: :a,
  update: {b: Sequel[:excluded][:b]}, update_where: {Sequel[:table][:status_id] => 1}).insert(a: 1, b: 2)
# INSERT INTO TABLE (a, b) VALUES (1, 2)
# ON CONFLICT (a) DO UPDATE SET b = excluded.b WHERE (table.status_id = 1)



769
770
771
772
773
774
775
776
777
778
779
780
781
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 769

def insert_conflict(opts = :ignore)
  case opts
  when Symbol, String
    unless INSERT_CONFLICT_RESOLUTIONS.include?(opts.to_s.upcase)
      raise Error, "Invalid symbol or string passed to Dataset#insert_conflict: #{opts.inspect}.  The allowed values are: :rollback, :abort, :fail, :ignore, or :replace"
    end
    clone(:insert_conflict => opts)
  when Hash
    clone(:insert_on_conflict => opts)
  else
    raise Error, "Invalid value passed to Dataset#insert_conflict: #{opts.inspect}, should use a symbol or a hash"
  end
end

#insert_ignore ⇒ Object

Ignore uniqueness/exclusion violations when inserting, using INSERT OR IGNORE. Exists mostly for compatibility to MySQL’s insert_ignore. Example:

DB[:table].insert_ignore.insert(a: 1, b: 2)
# INSERT OR IGNORE INTO TABLE (a, b) VALUES (1, 2)



788
789
790
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 788

def insert_ignore
  insert_conflict(:ignore)
end

#insert_select(*values) ⇒ Object

Support insert select for associations, so that the model code can use returning instead of a separate query.



698
699
700
701
702
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 698

def insert_select(*values)
  return unless supports_insert_select?
  # Handle case where query does not return a row
  server?(:default).with_sql_first(insert_select_sql(*values)) || false
end

#insert_select_sql(*values) ⇒ Object

The SQL to use for an insert_select, adds a RETURNING clause to the insert unless the RETURNING clause is already present.



706
707
708
709
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 706

def insert_select_sql(*values)
  ds = opts[:returning] ? self : returning
  ds.insert_sql(*values)
end

#quoted_identifier_append(sql, c) ⇒ Object

SQLite uses the nonstandard ‘ (backtick) for quoting identifiers.



712
713
714
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 712

def quoted_identifier_append(sql, c)
  sql << '`' << c.to_s.gsub('`', '``') << '`'
end

#returning(*values) ⇒ Object

Automatically add aliases to RETURNING values to work around SQLite bug.

Raises:



793
794
795
796
797
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 793

def returning(*values)
  return super if values.empty?
  raise Error, "RETURNING is not supported on #{db.database_type}" unless supports_returning?(:insert)
  clone(:returning=>_returning_values(values).freeze)
end

#select(*cols) ⇒ Object

When a qualified column is selected on SQLite and the qualifier is a subselect, the column name used is the full qualified name (including the qualifier) instead of just the column name. To get correct column names, you must use an alias.



720
721
722
723
724
725
726
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 720

def select(*cols)
  if ((f = @opts[:from]) && f.any?{|t| t.is_a?(Dataset) || (t.is_a?(SQL::AliasedExpression) && t.expression.is_a?(Dataset))}) || ((j = @opts[:join]) && j.any?{|t| t.table.is_a?(Dataset)})
    super(*cols.map{|c| alias_qualified_column(c)})
  else
    super
  end
end

#supports_cte?(type = :select) ⇒ Boolean

SQLite 3.8.3+ supports common table expressions.

Returns:

  • (Boolean) 


800
801
802
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 800

def supports_cte?(type=:select)
  db.sqlite_version >= 30803
end

#supports_cte_in_subqueries? ⇒ Boolean

SQLite supports CTEs in subqueries if it supports CTEs.

Returns:

  • (Boolean) 


805
806
807
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 805

def supports_cte_in_subqueries?
  supports_cte?
end

#supports_deleting_joins? ⇒ Boolean

SQLite does not support deleting from a joined dataset

Returns:

  • (Boolean) 


815
816
817
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 815

def supports_deleting_joins?
  false
end

#supports_derived_column_lists? ⇒ Boolean

SQLite does not support table aliases with column aliases

Returns:

  • (Boolean) 


810
811
812
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 810

def supports_derived_column_lists?
  false
end

#supports_intersect_except_all? ⇒ Boolean

SQLite does not support INTERSECT ALL or EXCEPT ALL

Returns:

  • (Boolean) 


820
821
822
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 820

def supports_intersect_except_all?
  false
end

#supports_is_true? ⇒ Boolean

SQLite does not support IS TRUE

Returns:

  • (Boolean) 


825
826
827
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 825

def supports_is_true?
  false
end

#supports_modifying_joins? ⇒ Boolean

SQLite 3.33.0 supports modifying joined datasets

Returns:

  • (Boolean) 


830
831
832
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 830

def supports_modifying_joins?
  db.sqlite_version >= 33300
end

#supports_multiple_column_in? ⇒ Boolean

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

Returns:

  • (Boolean) 


835
836
837
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 835

def supports_multiple_column_in?
  false
end

#supports_returning?(_) ⇒ Boolean

SQLite 3.35.0 supports RETURNING on INSERT/UPDATE/DELETE.

Returns:

  • (Boolean) 


840
841
842
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 840

def supports_returning?(_)
  db.sqlite_version >= 33500
end

#supports_timestamp_timezones? ⇒ Boolean

SQLite supports timezones in literal timestamps, since it stores them as text. But using timezones in timestamps breaks SQLite datetime functions, so we allow the user to override the default per database.

Returns:

  • (Boolean) 


847
848
849
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 847

def supports_timestamp_timezones?
  db.use_timestamp_timezones?
end

#supports_where_true? ⇒ Boolean

SQLite cannot use WHERE ‘t’.

Returns:

  • (Boolean) 


852
853
854
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 852

def supports_where_true?
  false
end

#supports_window_clause? ⇒ Boolean

SQLite 3.28+ supports the WINDOW clause.

Returns:

  • (Boolean) 


857
858
859
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 857

def supports_window_clause?
  db.sqlite_version >= 32800
end

#supports_window_function_frame_option?(option) ⇒ Boolean

SQLite 3.28.0+ supports all window frame options that Sequel supports

Returns:

  • (Boolean) 


870
871
872
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 870

def supports_window_function_frame_option?(option)
  db.sqlite_version >= 32800 ? true : super
end

#supports_window_functions? ⇒ Boolean

SQLite 3.25+ supports window functions. However, support is only enabled on SQLite 3.26.0+ because internal Sequel usage of window functions to implement eager loading of limited associations triggers an SQLite crash bug in versions 3.25.0-3.25.3.

Returns:

  • (Boolean) 


865
866
867
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 865

def supports_window_functions?
  db.sqlite_version >= 32600
end