module Sequel::CoreRefinements

Return a Sequel::SQL::BooleanExpression created from this hash, matching all of the conditions in this hash and the condition specified by the given argument.

{:a=>1} & :b # SQL: a = 1 AND b
{:a=>true} & ~:b # SQL: a IS TRUE AND NOT b

Return a Sequel::SQL::CaseExpression with this array as the conditions and the given default value and expression.

[[{:a=>[2,3]}, 1]].case(0) # SQL: CASE WHEN a IN (2, 3) THEN 1 ELSE 0 END
[[:a, 1], [:b, 2]].case(:d, :c) # SQL: CASE c WHEN a THEN 1 WHEN b THEN 2 ELSE d END

Returns receiver wrapped in an Sequel::SQL::Identifier. Usually used to prevent splitting the symbol.

:a__b # SQL: "a"."b"
:a__b.identifier # SQL: "a__b"

Converts a string into a Sequel::LiteralString, in order to override string literalization, e.g.:

DB[:items].filter(:abc => 'def').sql #=>
  "SELECT * FROM items WHERE (abc = 'def')"

DB[:items].filter(:abc => 'def'.lit).sql #=>
  "SELECT * FROM items WHERE (abc = def)"

You can also provide arguments, to create a Sequel::SQL::PlaceholderLiteralString:

DB[:items].select{|o| o.count('DISTINCT ?'.lit(:a))}.sql #=>
  "SELECT count(DISTINCT a) FROM items"

Return a Sequel::SQL::BooleanExpression created from this array, matching all of the conditions. Rarely do you need to call this explicitly, as Sequel generally assumes that arrays of two element arrays specify this type of condition. One case where it can be necessary to use this is if you are using the object as a value in a filter hash and want to use the = operator instead of the IN operator (which is used by default for arrays of two element arrays).

[[:a, true]].sql_expr # SQL: a IS TRUE
[[:a, 1], [:b, [2, 3]]].sql_expr # SQL: a = 1 AND b IN (2, 3)

Returns a Sequel::SQL::Function with this as the function name, and the given arguments. This is aliased as Symbol#[] if the RUBY_VERSION is less than 1.9.0. Ruby 1.9 defines Symbol#[], and Sequel doesn’t override methods defined by ruby itself.

:now.sql_function # SQL: now()
:sum.sql_function(:a) # SQL: sum(a)
:concat.sql_function(:a, :b) # SQL: concat(a, b)

Return a Sequel::SQL::BooleanExpression created from this array, matching none of the conditions.

[[:a, true]].sql_negate # SQL: a IS NOT TRUE
[[:a, 1], [:b, [2, 3]]].sql_negate # SQL: a != 1 AND b NOT IN (2, 3)

Return a Sequel::SQL::BooleanExpression created from this array, matching any of the conditions.

[[:a, true]].sql_or # SQL: a IS TRUE
[[:a, 1], [:b, [2, 3]]].sql_or # SQL: a = 1 OR b IN (2, 3)

Return a Sequel::SQL::StringExpression representing an SQL string made up of the concatenation of this array’s elements. If an argument is passed it is used in between each element of the array in the SQL concatenation.

[:a].sql_string_join # SQL: a
[:a, :b].sql_string_join # SQL: a || b
[:a, 'b'].sql_string_join # SQL: a || 'b'
['a', :b].sql_string_join(' ') # SQL: 'a' || ' ' || b

Return a Sequel::SQL::ValueList created from this array. Used if this array contains all two element arrays and you want it treated as an SQL value list (IN predicate) instead of as a conditions specifier (similar to a hash). This is not necessary if you are using this array as a value in a filter, but may be necessary if you are using it as a value with placeholder SQL:

DB[:a].filter([:a, :b]=>[[1, 2], [3, 4]]) # SQL: (a, b) IN ((1, 2), (3, 4))
DB[:a].filter('(a, b) IN ?', [[1, 2], [3, 4]]) # SQL: (a, b) IN ((1 = 2) AND (3 = 4))
DB[:a].filter('(a, b) IN ?', [[1, 2], [3, 4]].sql_value_list) # SQL: (a, b) IN ((1, 2), (3, 4))

Returns a Sequel::SQL::Blob that holds the same data as this string. Blobs provide proper escaping of binary data.

Return a Sequel::SQL::BooleanExpression created from this hash, matching all of the conditions in this hash or the condition specified by the given argument.

{:a=>1} | :b # SQL: a = 1 OR b
{:a=>true} | ~:b # SQL: a IS TRUE OR NOT b

Return a Sequel::SQL::BooleanExpression created from this array, not matching all of the conditions.

~[[:a, true]] # SQL: a IS NOT TRUE
~[[:a, 1], [:b, [2, 3]]] # SQL: a != 1 OR b NOT IN (2, 3)