Class: Hash

Inherits:
Object show all
Defined in:
lib/sequel/lib/sequel/core_sql.rb

Overview

Sequel extends the Hash class to add methods to implement the SQL DSL.

Instance Method Summary collapse

Instance Method Details

#&(ce) ⇒ Object

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


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# File 'lib/sequel/lib/sequel/core_sql.rb', line 111

def &(ce)
  ::Sequel::SQL::BooleanExpression.new(:AND, self, ce)
end

#case(default, expression = nil) ⇒ Object

Return a Sequel::SQL::CaseExpression with this hash as the conditions and the given default value. Note that the order of the conditions will be arbitrary, so all conditions should be orthogonal.

{{: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
                              #  or: CASE c WHEN b THEN 2 WHEN a THEN 1 ELSE d END


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# File 'lib/sequel/lib/sequel/core_sql.rb', line 141

def case(default, expression = nil)
  ::Sequel::SQL::CaseExpression.new(to_a, default, expression)
end

#sql_exprObject

Return a Sequel::SQL::BooleanExpression created from this hash, matching all of the conditions. Rarely do you need to call this explicitly, as Sequel generally assumes that hashes 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/lib/sequel/core_sql.rb', line 151

def sql_expr
  ::Sequel::SQL::BooleanExpression.from_value_pairs(self)
end

#sql_negateObject

Return a Sequel::SQL::BooleanExpression created from this hash, 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/lib/sequel/core_sql.rb', line 160

def sql_negate
  ::Sequel::SQL::BooleanExpression.from_value_pairs(self, :AND, true)
end

#sql_orObject

Return a Sequel::SQL::BooleanExpression created from this hash, 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/lib/sequel/core_sql.rb', line 169

def sql_or
  ::Sequel::SQL::BooleanExpression.from_value_pairs(self, :OR)
end

#|(ce) ⇒ Object

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


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# File 'lib/sequel/lib/sequel/core_sql.rb', line 121

def |(ce)
  ::Sequel::SQL::BooleanExpression.new(:OR, self, ce)
end

#~Object

Return a Sequel::SQL::BooleanExpression created from this hash, 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/lib/sequel/core_sql.rb', line 130

def ~
  ::Sequel::SQL::BooleanExpression.from_value_pairs(self, :OR, true)
end