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 



511
512
513
514
515
516
517
518
519
520
521
522
523
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 511

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.



527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 527

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.



572
573
574
575
576
577
578
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 572

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

#delete ⇒ 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.



583
584
585
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 583

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



590
591
592
593
594
595
596
597
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 590

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) 


600
601
602
603
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 600

def having(*cond)
  raise(InvalidOperation, "Can only specify a HAVING clause on a grouped dataset") unless @opts[:group]
  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)



663
664
665
666
667
668
669
670
671
672
673
674
675
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 663

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)



682
683
684
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 682

def insert_ignore
  insert_conflict(:ignore)
end

#quoted_identifier_append(sql, c) ⇒ Object

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



606
607
608
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 606

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



614
615
616
617
618
619
620
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 614

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) 


687
688
689
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 687

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) 


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

def supports_cte_in_subqueries?
  supports_cte?
end

#supports_derived_column_lists? ⇒ Boolean

SQLite does not support table aliases with column aliases

Returns:

  • (Boolean) 


697
698
699
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 697

def supports_derived_column_lists?
  false
end

#supports_intersect_except_all? ⇒ Boolean

SQLite does not support INTERSECT ALL or EXCEPT ALL

Returns:

  • (Boolean) 


702
703
704
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 702

def supports_intersect_except_all?
  false
end

#supports_is_true? ⇒ Boolean

SQLite does not support IS TRUE

Returns:

  • (Boolean) 


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

def supports_is_true?
  false
end

#supports_multiple_column_in? ⇒ Boolean

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

Returns:

  • (Boolean) 


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

def supports_multiple_column_in?
  false
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) 


719
720
721
 
# File 'lib/sequel/adapters/shared/sqlite.rb', line 719

def supports_timestamp_timezones?
  db.use_timestamp_timezones?
end

#supports_where_true? ⇒ Boolean

SQLite cannot use WHERE ‘t’.

Returns:

  • (Boolean) 


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

def supports_where_true?
  false
end