module Sequel::SQLite::DatasetMethods
Constants
- CONSTANT_MAP
- EXTRACT_MAP
- INSERT_CONFLICT_RESOLUTIONS
The allowed values for
insert_conflict
Public Instance Methods
# File lib/sequel/adapters/shared/sqlite.rb 566 def cast_sql_append(sql, expr, type) 567 if type == Time or type == DateTime 568 sql << "datetime(" 569 literal_append(sql, expr) 570 sql << ')' 571 elsif type == Date 572 sql << "date(" 573 literal_append(sql, expr) 574 sql << ')' 575 else 576 super 577 end 578 end
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.
# File lib/sequel/adapters/shared/sqlite.rb 582 def complex_expression_sql_append(sql, op, args) 583 case op 584 when :"NOT LIKE", :"NOT ILIKE" 585 sql << 'NOT ' 586 complex_expression_sql_append(sql, (op == :"NOT ILIKE" ? :ILIKE : :LIKE), args) 587 when :^ 588 complex_expression_arg_pairs_append(sql, args){|a, b| Sequel.lit(["((~(", " & ", ")) & (", " | ", "))"], a, b, a, b)} 589 when :** 590 unless (exp = args[1]).is_a?(Integer) 591 raise(Sequel::Error, "can only emulate exponentiation on SQLite if exponent is an integer, given #{exp.inspect}") 592 end 593 case exp 594 when 0 595 sql << '1' 596 else 597 sql << '(' 598 arg = args[0] 599 if exp < 0 600 invert = true 601 exp = exp.abs 602 sql << '(1.0 / (' 603 end 604 (exp - 1).times do 605 literal_append(sql, arg) 606 sql << " * " 607 end 608 literal_append(sql, arg) 609 sql << ')' 610 if invert 611 sql << "))" 612 end 613 end 614 when :extract 615 part = args[0] 616 raise(Sequel::Error, "unsupported extract argument: #{part.inspect}") unless format = EXTRACT_MAP[part] 617 sql << "CAST(strftime(" << format << ', ' 618 literal_append(sql, args[1]) 619 sql << ') AS ' << (part == :second ? 'NUMERIC' : 'INTEGER') << ')' 620 else 621 super 622 end 623 end
SQLite
has CURRENT_TIMESTAMP and related constants in UTC instead of in localtime, so convert those constants to local time.
# File lib/sequel/adapters/shared/sqlite.rb 627 def constant_sql_append(sql, constant) 628 if (c = CONSTANT_MAP[constant]) && !db.current_timestamp_utc 629 sql << c 630 else 631 super 632 end 633 end
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.
# File lib/sequel/adapters/shared/sqlite.rb 638 def delete 639 @opts[:where] ? super : where(1=>1).delete 640 end
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 645 def explain(opts=nil) 646 # Load the PrettyTable class, needed for explain output 647 Sequel.extension(:_pretty_table) unless defined?(Sequel::PrettyTable) 648 649 ds = db.send(:metadata_dataset).clone(:sql=>"EXPLAIN #{select_sql}") 650 rows = ds.all 651 Sequel::PrettyTable.string(rows, ds.columns) 652 end
HAVING requires GROUP BY on SQLite
# File lib/sequel/adapters/shared/sqlite.rb 655 def having(*cond) 656 raise(InvalidOperation, "Can only specify a HAVING clause on a grouped dataset") unless @opts[:group] 657 super 658 end
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 718 def insert_conflict(opts = :ignore) 719 case opts 720 when Symbol, String 721 unless INSERT_CONFLICT_RESOLUTIONS.include?(opts.to_s.upcase) 722 raise Error, "Invalid symbol or string passed to Dataset#insert_conflict: #{opts.inspect}. The allowed values are: :rollback, :abort, :fail, :ignore, or :replace" 723 end 724 clone(:insert_conflict => opts) 725 when Hash 726 clone(:insert_on_conflict => opts) 727 else 728 raise Error, "Invalid value passed to Dataset#insert_conflict: #{opts.inspect}, should use a symbol or a hash" 729 end 730 end
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 737 def insert_ignore 738 insert_conflict(:ignore) 739 end
SQLite
uses the nonstandard ` (backtick) for quoting identifiers.
# File lib/sequel/adapters/shared/sqlite.rb 661 def quoted_identifier_append(sql, c) 662 sql << '`' << c.to_s.gsub('`', '``') << '`' 663 end
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.
# File lib/sequel/adapters/shared/sqlite.rb 669 def select(*cols) 670 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)}) 671 super(*cols.map{|c| alias_qualified_column(c)}) 672 else 673 super 674 end 675 end
SQLite
3.8.3+ supports common table expressions.
# File lib/sequel/adapters/shared/sqlite.rb 742 def supports_cte?(type=:select) 743 db.sqlite_version >= 30803 744 end
SQLite
supports CTEs in subqueries if it supports CTEs.
# File lib/sequel/adapters/shared/sqlite.rb 747 def supports_cte_in_subqueries? 748 supports_cte? 749 end
SQLite
does not support table aliases with column aliases
# File lib/sequel/adapters/shared/sqlite.rb 752 def supports_derived_column_lists? 753 false 754 end
SQLite
does not support INTERSECT ALL or EXCEPT ALL
# File lib/sequel/adapters/shared/sqlite.rb 757 def supports_intersect_except_all? 758 false 759 end
SQLite
does not support IS TRUE
# File lib/sequel/adapters/shared/sqlite.rb 762 def supports_is_true? 763 false 764 end
SQLite
does not support multiple columns for the IN/NOT IN operators
# File lib/sequel/adapters/shared/sqlite.rb 767 def supports_multiple_column_in? 768 false 769 end
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 774 def supports_timestamp_timezones? 775 db.use_timestamp_timezones? 776 end
SQLite
cannot use WHERE 't'.
# File lib/sequel/adapters/shared/sqlite.rb 779 def supports_where_true? 780 false 781 end
SQLite
3.28+ supports the WINDOW clause.
# File lib/sequel/adapters/shared/sqlite.rb 784 def supports_window_clause? 785 db.sqlite_version >= 32800 786 end
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 792 def supports_window_functions? 793 db.sqlite_version >= 32600 794 end
Private Instance Methods
SQLite
treats a DELETE with no WHERE clause as a TRUNCATE
# File lib/sequel/adapters/shared/sqlite.rb 944 def _truncate_sql(table) 945 "DELETE FROM #{table}" 946 end
If col is a qualified column, alias it to the same as the column name
# File lib/sequel/adapters/shared/sqlite.rb 812 def alias_qualified_column(col) 813 case col 814 when Symbol 815 t, c, a = split_symbol(col) 816 if t && !a 817 alias_qualified_column(SQL::QualifiedIdentifier.new(t, c)) 818 else 819 col 820 end 821 when SQL::QualifiedIdentifier 822 SQL::AliasedExpression.new(col, col.column) 823 else 824 col 825 end 826 end
SQLite
uses string literals instead of identifiers in AS clauses.
# File lib/sequel/adapters/shared/sqlite.rb 804 def as_sql_append(sql, aliaz, column_aliases=nil) 805 raise Error, "sqlite does not support derived column lists" if column_aliases 806 aliaz = aliaz.value if aliaz.is_a?(SQL::Identifier) 807 sql << ' AS ' 808 literal_append(sql, aliaz.to_s) 809 end
SQLite
supports a maximum of 500 rows in a VALUES clause.
# File lib/sequel/adapters/shared/sqlite.rb 829 def default_import_slice 830 500 831 end
SQL
fragment specifying a list of identifiers
# File lib/sequel/adapters/shared/sqlite.rb 834 def identifier_list(columns) 835 columns.map{|i| quote_identifier(i)}.join(', ') 836 end
Add OR clauses to SQLite
INSERT statements
# File lib/sequel/adapters/shared/sqlite.rb 839 def insert_conflict_sql(sql) 840 if resolution = @opts[:insert_conflict] 841 sql << " OR " << resolution.to_s.upcase 842 end 843 end
Add ON CONFLICT clause if it should be used
# File lib/sequel/adapters/shared/sqlite.rb 846 def insert_on_conflict_sql(sql) 847 if opts = @opts[:insert_on_conflict] 848 sql << " ON CONFLICT" 849 850 if target = opts[:constraint] 851 sql << " ON CONSTRAINT " 852 identifier_append(sql, target) 853 elsif target = opts[:target] 854 sql << ' ' 855 identifier_append(sql, Array(target)) 856 if conflict_where = opts[:conflict_where] 857 sql << " WHERE " 858 literal_append(sql, conflict_where) 859 end 860 end 861 862 if values = opts[:update] 863 sql << " DO UPDATE SET " 864 update_sql_values_hash(sql, values) 865 if update_where = opts[:update_where] 866 sql << " WHERE " 867 literal_append(sql, update_where) 868 end 869 else 870 sql << " DO NOTHING" 871 end 872 end 873 end
SQLite
uses a preceding X for hex escaping strings
# File lib/sequel/adapters/shared/sqlite.rb 876 def literal_blob_append(sql, v) 877 sql << "X'" << v.unpack("H*").first << "'" 878 end
Respect the database integer_booleans setting, using 0 or 'f'.
# File lib/sequel/adapters/shared/sqlite.rb 881 def literal_false 882 @db.integer_booleans ? '0' : "'f'" 883 end
Respect the database integer_booleans setting, using 1 or 't'.
# File lib/sequel/adapters/shared/sqlite.rb 886 def literal_true 887 @db.integer_booleans ? '1' : "'t'" 888 end
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 892 def multi_insert_sql_strategy 893 db.sqlite_version >= 30711 ? :values : :union 894 end
Emulate the char_length function with length
# File lib/sequel/adapters/shared/sqlite.rb 897 def native_function_name(emulated_function) 898 if emulated_function == :char_length 899 'length' 900 else 901 super 902 end 903 end
SQLite
supports NULLS FIRST/LAST natively in 3.30+.
# File lib/sequel/adapters/shared/sqlite.rb 906 def requires_emulating_nulls_first? 907 db.sqlite_version < 33000 908 end
SQLite
does not support FOR UPDATE, but silently ignore it instead of raising an error for compatibility with other databases.
# File lib/sequel/adapters/shared/sqlite.rb 913 def select_lock_sql(sql) 914 super unless @opts[:lock] == :update 915 end
# File lib/sequel/adapters/shared/sqlite.rb 917 def select_only_offset_sql(sql) 918 sql << " LIMIT -1 OFFSET " 919 literal_append(sql, @opts[:offset]) 920 end
Support VALUES clause instead of the SELECT clause to return rows.
# File lib/sequel/adapters/shared/sqlite.rb 923 def select_values_sql(sql) 924 sql << "VALUES " 925 expression_list_append(sql, opts[:values]) 926 end
SQLite
does not support CTEs directly inside UNION/INTERSECT/EXCEPT.
# File lib/sequel/adapters/shared/sqlite.rb 929 def supports_cte_in_compounds? 930 false 931 end
SQLite
3.30 supports the FILTER clause for aggregate functions.
# File lib/sequel/adapters/shared/sqlite.rb 934 def supports_filtered_aggregates? 935 db.sqlite_version >= 33000 936 end
SQLite
supports quoted function names.
# File lib/sequel/adapters/shared/sqlite.rb 939 def supports_quoted_function_names? 940 true 941 end