Class: Array
Overview
Sequel extends the Array class to add methods to implement the SQL DSL. Most of these methods require that the array not be empty and that it must consist solely of other arrays that have exactly two elements.
Instance Method Summary collapse
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#all_two_pairs? ⇒ Boolean
True if the array is not empty and all of its elements are arrays of size 2, false otherwise.
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#case(default, expression = nil) ⇒ Object
Return a Sequel::SQL::CaseExpression with this array as the conditions and the given default value and expression.
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#sql_array ⇒ Object
Return a Sequel::SQL::Array created from this array.
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#sql_expr ⇒ Object
Return a Sequel::SQL::BooleanExpression created from this array, matching all of the conditions.
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#sql_negate ⇒ Object
Return a Sequel::SQL::BooleanExpression created from this array, matching none of the conditions.
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#sql_or ⇒ Object
Return a Sequel::SQL::BooleanExpression created from this array, matching any of the conditions.
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#sql_string_join(joiner = nil) ⇒ Object
Return a Sequel::SQL::BooleanExpression representing an SQL string made up of the concatenation of this array’s elements.
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#~ ⇒ Object
Return a Sequel::SQL::BooleanExpression created from this array, not matching all of the conditions.
Instance Method Details
#all_two_pairs? ⇒ Boolean
True if the array is not empty and all of its elements are arrays of size 2, false otherwise. This is used to determine if the array could be a specifier of conditions, used similarly to a hash but allowing for duplicate keys and a specific order.
[].to_a.all_two_pairs? # => false
[:a].to_a.all_two_pairs? # => false
[[:b]].to_a.all_two_pairs? # => false
[[:a, 1]].to_a.all_two_pairs? # => true
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# File 'lib/sequel/core_sql.rb', line 23 def all_two_pairs? !empty? && all?{|i| (Array === i) && (i.length == 2)} end |
#case(default, expression = nil) ⇒ Object
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
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# File 'lib/sequel/core_sql.rb', line 32 def case(default, expression = nil) ::Sequel::SQL::CaseExpression.new(self, default, expression) end |
#sql_array ⇒ Object
Return a Sequel::SQL::Array created from this array. Used if this array contains all two pairs and you want it treated as an SQL array instead of a ordered hash-like conditions.
[[1, 2], [3, 4]] # SQL: 1 = 2 AND 3 = 4
[[1, 2], [3, 4]].sql_array # SQL: ((1, 2), (3, 4))
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# File 'lib/sequel/core_sql.rb', line 42 def sql_array ::Sequel::SQL::SQLArray.new(self) end |
#sql_expr ⇒ Object
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 all two pairs specify this type of condition.
[[:a, true]].sql_expr # SQL: a IS TRUE
[[:a, 1], [:b, [2, 3]]].sql_expr # SQL: a = 1 AND b IN (2, 3)
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# File 'lib/sequel/core_sql.rb', line 52 def sql_expr sql_expr_if_all_two_pairs end |
#sql_negate ⇒ Object
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)
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# File 'lib/sequel/core_sql.rb', line 61 def sql_negate sql_expr_if_all_two_pairs(:AND, true) end |
#sql_or ⇒ Object
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)
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# File 'lib/sequel/core_sql.rb', line 70 def sql_or sql_expr_if_all_two_pairs(:OR) end |
#sql_string_join(joiner = nil) ⇒ Object
Return a Sequel::SQL::BooleanExpression 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. This does not require that the array be made up of all two pairs.
[: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
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# File 'lib/sequel/core_sql.rb', line 83 def sql_string_join(joiner=nil) if joiner args = zip([joiner]*length).flatten args.pop else args = self end args = args.collect{|a| [Symbol, ::Sequel::SQL::Expression, ::Sequel::LiteralString, TrueClass, FalseClass, NilClass].any?{|c| a.is_a?(c)} ? a : a.to_s} ::Sequel::SQL::StringExpression.new(:'||', *args) end |
#~ ⇒ Object
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)
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# File 'lib/sequel/core_sql.rb', line 10 def ~ sql_expr_if_all_two_pairs(:OR, true) end |