module Sequel::SQLite::DatasetMethods

Constants

CONSTANT_MAP
EXTRACT_MAP
INSERT_CONFLICT_RESOLUTIONS

The allowed values for insert_conflict

Public Instance Methods

cast_sql_append(sql, expr, type) click to toggle source
Calls superclass method
    # File lib/sequel/adapters/shared/sqlite.rb
570 def cast_sql_append(sql, expr, type)
571   if type == Time or type == DateTime
572     sql << "datetime("
573     literal_append(sql, expr)
574     sql << ')'
575   elsif type == Date
576     sql << "date("
577     literal_append(sql, expr)
578     sql << ')'
579   else
580     super
581   end
582 end
complex_expression_sql_append(sql, op, args) click to toggle source

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.

Calls superclass method
    # File lib/sequel/adapters/shared/sqlite.rb
586 def complex_expression_sql_append(sql, op, args)
587   case op
588   when :"NOT LIKE", :"NOT ILIKE"
589     sql << 'NOT '
590     complex_expression_sql_append(sql, (op == :"NOT ILIKE" ? :ILIKE : :LIKE), args)
591   when :^
592     complex_expression_arg_pairs_append(sql, args){|a, b| Sequel.lit(["((~(", " & ", ")) & (", " | ", "))"], a, b, a, b)}
593   when :**
594     unless (exp = args[1]).is_a?(Integer)
595       raise(Sequel::Error, "can only emulate exponentiation on SQLite if exponent is an integer, given #{exp.inspect}")
596     end
597     case exp
598     when 0
599       sql << '1'
600     else
601       sql << '('
602       arg = args[0]
603       if exp < 0
604         invert = true
605         exp = exp.abs
606         sql << '(1.0 / ('
607       end
608       (exp - 1).times do 
609         literal_append(sql, arg)
610         sql << " * "
611       end
612       literal_append(sql, arg)
613       sql << ')'
614       if invert
615         sql << "))"
616       end
617     end
618   when :extract
619     part = args[0]
620     raise(Sequel::Error, "unsupported extract argument: #{part.inspect}") unless format = EXTRACT_MAP[part]
621     sql << "CAST(strftime(" << format << ', '
622     literal_append(sql, args[1])
623     sql << ') AS ' << (part == :second ? 'NUMERIC' : 'INTEGER') << ')'
624   else
625     super
626   end
627 end
constant_sql_append(sql, constant) click to toggle source

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

Calls superclass method
    # File lib/sequel/adapters/shared/sqlite.rb
631 def constant_sql_append(sql, constant)
632   if (c = CONSTANT_MAP[constant]) && !db.current_timestamp_utc
633     sql << c
634   else
635     super
636   end
637 end
delete() click to toggle source

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.

Calls superclass method
    # File lib/sequel/adapters/shared/sqlite.rb
642 def delete
643   @opts[:where] ? super : where(1=>1).delete
644 end
explain(opts=nil) click to toggle source

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.

    # File lib/sequel/adapters/shared/sqlite.rb
649 def explain(opts=nil)
650   # Load the PrettyTable class, needed for explain output
651   Sequel.extension(:_pretty_table) unless defined?(Sequel::PrettyTable)
652 
653   ds = db.send(:metadata_dataset).clone(:sql=>"EXPLAIN #{select_sql}")
654   rows = ds.all
655   Sequel::PrettyTable.string(rows, ds.columns)
656 end
having(*cond) click to toggle source

HAVING requires GROUP BY on SQLite

Calls superclass method
    # File lib/sequel/adapters/shared/sqlite.rb
659 def having(*cond)
660   raise(InvalidOperation, "Can only specify a HAVING clause on a grouped dataset") unless @opts[:group]
661   super
662 end
insert_conflict(opts = :ignore) click to toggle source

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)
    # File lib/sequel/adapters/shared/sqlite.rb
722 def insert_conflict(opts = :ignore)
723   case opts
724   when Symbol, String
725     unless INSERT_CONFLICT_RESOLUTIONS.include?(opts.to_s.upcase)
726       raise Error, "Invalid symbol or string passed to Dataset#insert_conflict: #{opts.inspect}.  The allowed values are: :rollback, :abort, :fail, :ignore, or :replace"
727     end
728     clone(:insert_conflict => opts)
729   when Hash
730     clone(:insert_on_conflict => opts)
731   else
732     raise Error, "Invalid value passed to Dataset#insert_conflict: #{opts.inspect}, should use a symbol or a hash"
733   end
734 end
insert_ignore() click to toggle source

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)
    # File lib/sequel/adapters/shared/sqlite.rb
741 def insert_ignore
742   insert_conflict(:ignore)
743 end
quoted_identifier_append(sql, c) click to toggle source

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

    # File lib/sequel/adapters/shared/sqlite.rb
665 def quoted_identifier_append(sql, c)
666   sql << '`' << c.to_s.gsub('`', '``') << '`'
667 end
select(*cols) click to toggle source

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.

Calls superclass method
    # File lib/sequel/adapters/shared/sqlite.rb
673 def select(*cols)
674   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)})
675     super(*cols.map{|c| alias_qualified_column(c)})
676   else
677     super
678   end
679 end
supports_cte?(type=:select) click to toggle source

SQLite 3.8.3+ supports common table expressions.

    # File lib/sequel/adapters/shared/sqlite.rb
746 def supports_cte?(type=:select)
747   db.sqlite_version >= 30803
748 end
supports_cte_in_subqueries?() click to toggle source

SQLite supports CTEs in subqueries if it supports CTEs.

    # File lib/sequel/adapters/shared/sqlite.rb
751 def supports_cte_in_subqueries?
752   supports_cte?
753 end
supports_deleting_joins?() click to toggle source

SQLite does not support deleting from a joined dataset

    # File lib/sequel/adapters/shared/sqlite.rb
761 def supports_deleting_joins?
762   false
763 end
supports_derived_column_lists?() click to toggle source

SQLite does not support table aliases with column aliases

    # File lib/sequel/adapters/shared/sqlite.rb
756 def supports_derived_column_lists?
757   false
758 end
supports_intersect_except_all?() click to toggle source

SQLite does not support INTERSECT ALL or EXCEPT ALL

    # File lib/sequel/adapters/shared/sqlite.rb
766 def supports_intersect_except_all?
767   false
768 end
supports_is_true?() click to toggle source

SQLite does not support IS TRUE

    # File lib/sequel/adapters/shared/sqlite.rb
771 def supports_is_true?
772   false
773 end
supports_modifying_joins?() click to toggle source

SQLite 3.33.0 supports modifying joined datasets

    # File lib/sequel/adapters/shared/sqlite.rb
776 def supports_modifying_joins?
777   db.sqlite_version >= 33300
778 end
supports_multiple_column_in?() click to toggle source

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

    # File lib/sequel/adapters/shared/sqlite.rb
781 def supports_multiple_column_in?
782   false
783 end
supports_timestamp_timezones?() click to toggle source

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.

    # File lib/sequel/adapters/shared/sqlite.rb
788 def supports_timestamp_timezones?
789   db.use_timestamp_timezones?
790 end
supports_where_true?() click to toggle source

SQLite cannot use WHERE 't'.

    # File lib/sequel/adapters/shared/sqlite.rb
793 def supports_where_true?
794   false
795 end
supports_window_clause?() click to toggle source

SQLite 3.28+ supports the WINDOW clause.

    # File lib/sequel/adapters/shared/sqlite.rb
798 def supports_window_clause?
799   db.sqlite_version >= 32800
800 end
supports_window_function_frame_option?(option) click to toggle source

SQLite 3.28.0+ supports all window frame options that Sequel supports

Calls superclass method
    # File lib/sequel/adapters/shared/sqlite.rb
811 def supports_window_function_frame_option?(option)
812   db.sqlite_version >= 32800 ? true : super
813 end
supports_window_functions?() click to toggle source

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.

    # File lib/sequel/adapters/shared/sqlite.rb
806 def supports_window_functions?
807   db.sqlite_version >= 32600
808 end

Private Instance Methods

_truncate_sql(table) click to toggle source

SQLite treats a DELETE with no WHERE clause as a TRUNCATE

    # File lib/sequel/adapters/shared/sqlite.rb
965 def _truncate_sql(table)
966   "DELETE FROM #{table}"
967 end
alias_qualified_column(col) click to toggle source

If col is a qualified column, alias it to the same as the column name

    # File lib/sequel/adapters/shared/sqlite.rb
826 def alias_qualified_column(col)
827   case col
828   when Symbol
829     t, c, a = split_symbol(col)
830     if t && !a
831       alias_qualified_column(SQL::QualifiedIdentifier.new(t, c))
832     else
833       col
834     end
835   when SQL::QualifiedIdentifier
836     SQL::AliasedExpression.new(col, col.column)
837   else
838     col
839   end
840 end
as_sql_append(sql, aliaz, column_aliases=nil) click to toggle source

SQLite uses string literals instead of identifiers in AS clauses.

    # File lib/sequel/adapters/shared/sqlite.rb
818 def as_sql_append(sql, aliaz, column_aliases=nil)
819   raise Error, "sqlite does not support derived column lists" if column_aliases
820   aliaz = aliaz.value if aliaz.is_a?(SQL::Identifier)
821   sql << ' AS '
822   literal_append(sql, aliaz.to_s)
823 end
check_delete_allowed!()
check_insert_allowed!() click to toggle source

Raise an InvalidOperation exception if insert is not allowed for this dataset.

    # File lib/sequel/adapters/shared/sqlite.rb
843 def check_insert_allowed!
844   raise(InvalidOperation, "Grouped datasets cannot be modified") if opts[:group]
845   raise(InvalidOperation, "Joined datasets cannot be modified") if joined_dataset?
846 end
Also aliased as: check_delete_allowed!
default_import_slice() click to toggle source

SQLite supports a maximum of 500 rows in a VALUES clause.

    # File lib/sequel/adapters/shared/sqlite.rb
850 def default_import_slice
851   500
852 end
identifier_list(columns) click to toggle source

SQL fragment specifying a list of identifiers

    # File lib/sequel/adapters/shared/sqlite.rb
855 def identifier_list(columns)
856   columns.map{|i| quote_identifier(i)}.join(', ')
857 end
insert_conflict_sql(sql) click to toggle source

Add OR clauses to SQLite INSERT statements

    # File lib/sequel/adapters/shared/sqlite.rb
860 def insert_conflict_sql(sql)
861   if resolution = @opts[:insert_conflict]
862     sql << " OR " << resolution.to_s.upcase
863   end
864 end
insert_on_conflict_sql(sql) click to toggle source

Add ON CONFLICT clause if it should be used

    # File lib/sequel/adapters/shared/sqlite.rb
867 def insert_on_conflict_sql(sql)
868   if opts = @opts[:insert_on_conflict]
869     sql << " ON CONFLICT"
870 
871     if target = opts[:constraint] 
872       sql << " ON CONSTRAINT "
873       identifier_append(sql, target)
874     elsif target = opts[:target]
875       sql << ' '
876       identifier_append(sql, Array(target))
877       if conflict_where = opts[:conflict_where]
878         sql << " WHERE "
879         literal_append(sql, conflict_where)
880       end
881     end
882 
883     if values = opts[:update]
884       sql << " DO UPDATE SET "
885       update_sql_values_hash(sql, values)
886       if update_where = opts[:update_where]
887         sql << " WHERE "
888         literal_append(sql, update_where)
889       end
890     else
891       sql << " DO NOTHING"
892     end
893   end
894 end
literal_blob_append(sql, v) click to toggle source

SQLite uses a preceding X for hex escaping strings

    # File lib/sequel/adapters/shared/sqlite.rb
897 def literal_blob_append(sql, v)
898   sql <<  "X'" << v.unpack("H*").first << "'"
899 end
literal_false() click to toggle source

Respect the database integer_booleans setting, using 0 or 'f'.

    # File lib/sequel/adapters/shared/sqlite.rb
902 def literal_false
903   @db.integer_booleans ? '0' : "'f'"
904 end
literal_true() click to toggle source

Respect the database integer_booleans setting, using 1 or 't'.

    # File lib/sequel/adapters/shared/sqlite.rb
907 def literal_true
908   @db.integer_booleans ? '1' : "'t'"
909 end
multi_insert_sql_strategy() click to toggle source

SQLite only supporting multiple rows in the VALUES clause starting in 3.7.11. On older versions, fallback to using a UNION.

    # File lib/sequel/adapters/shared/sqlite.rb
913 def multi_insert_sql_strategy
914   db.sqlite_version >= 30711 ? :values : :union
915 end
native_function_name(emulated_function) click to toggle source

Emulate the char_length function with length

Calls superclass method
    # File lib/sequel/adapters/shared/sqlite.rb
918 def native_function_name(emulated_function)
919   if emulated_function == :char_length
920     'length'
921   else
922     super
923   end
924 end
requires_emulating_nulls_first?() click to toggle source

SQLite supports NULLS FIRST/LAST natively in 3.30+.

    # File lib/sequel/adapters/shared/sqlite.rb
927 def requires_emulating_nulls_first?
928   db.sqlite_version < 33000
929 end
select_lock_sql(sql) click to toggle source

SQLite does not support FOR UPDATE, but silently ignore it instead of raising an error for compatibility with other databases.

Calls superclass method
    # File lib/sequel/adapters/shared/sqlite.rb
934 def select_lock_sql(sql)
935   super unless @opts[:lock] == :update
936 end
select_only_offset_sql(sql) click to toggle source
    # File lib/sequel/adapters/shared/sqlite.rb
938 def select_only_offset_sql(sql)
939   sql << " LIMIT -1 OFFSET "
940   literal_append(sql, @opts[:offset])
941 end
select_values_sql(sql) click to toggle source

Support VALUES clause instead of the SELECT clause to return rows.

    # File lib/sequel/adapters/shared/sqlite.rb
944 def select_values_sql(sql)
945   sql << "VALUES "
946   expression_list_append(sql, opts[:values])
947 end
supports_cte_in_compounds?() click to toggle source

SQLite does not support CTEs directly inside UNION/INTERSECT/EXCEPT.

    # File lib/sequel/adapters/shared/sqlite.rb
950 def supports_cte_in_compounds?
951   false
952 end
supports_filtered_aggregates?() click to toggle source

SQLite 3.30 supports the FILTER clause for aggregate functions.

    # File lib/sequel/adapters/shared/sqlite.rb
955 def supports_filtered_aggregates?
956   db.sqlite_version >= 33000
957 end
supports_quoted_function_names?() click to toggle source

SQLite supports quoted function names.

    # File lib/sequel/adapters/shared/sqlite.rb
960 def supports_quoted_function_names?
961   true
962 end
update_from_sql(sql) click to toggle source

Use FROM to specify additional tables in an update query

    # File lib/sequel/adapters/shared/sqlite.rb
970 def update_from_sql(sql)
971   if(from = @opts[:from][1..-1]).empty?
972     raise(Error, 'Need multiple FROM tables if updating/deleting a dataset with JOINs') if @opts[:join]
973   else
974     sql << ' FROM '
975     source_list_append(sql, from)
976     select_join_sql(sql)
977   end
978 end
update_table_sql(sql) click to toggle source

Only include the primary table in the main update clause

    # File lib/sequel/adapters/shared/sqlite.rb
981 def update_table_sql(sql)
982   sql << ' '
983   source_list_append(sql, @opts[:from][0..0])
984 end