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Sequel::SQL::ComplexExpression

Represents a complex SQL expression, with a given operator and one or more attributes (which may also be ComplexExpressions, forming a tree). This class is the backbone of Sequel’s ruby expression DSL.

This is an abstract class that is not that useful by itself. The subclasses BooleanExpression, NumericExpression, and StringExpression define the behavior of the DSL via operators.

Constants

OPERTATOR_INVERSIONS

A hash of the opposite for each operator symbol, used for inverting objects.

MATHEMATICAL_OPERATORS

Standard mathematical operators used in NumericMethods

BITWISE_OPERATORS

Bitwise mathematical operators used in NumericMethods

INEQUALITY_OPERATORS

Inequality operators used in InequalityMethods

BOOLEAN_OPERATOR_METHODS

Hash of ruby operator symbols to SQL operators, used in BooleanMethods

IN_OPERATORS

Operators that use IN/NOT IN for inclusion/exclusion

IS_OPERATORS

Operators that use IS, used for special casing to override literal true/false values

TWO_ARITY_OPERATORS

Operator symbols that take exactly two arguments

N_ARITY_OPERATORS

Operator symbols that take one or more arguments

ONE_ARITY_OPERATORS

Operator symbols that take only a single argument

CUSTOM_EXPRESSIONS

Custom expressions that may have different syntax on different databases

CONSTANT_INVERSIONS

A hash of the opposite for each constant, used for inverting constants.

Attributes

args[R]

An array of args for this object

op[R]

The operator symbol for this object

Public Class Methods

new(op, *args) click to toggle source

Set the operator symbol and arguments for this object to the ones given. Convert all args that are hashes or arrays of two element arrays to BooleanExpressions, other than the second arg for an IN/NOT IN operator. Raise an Error if the operator doesn’t allow boolean input and a boolean argument is given. Raise an Error if the wrong number of arguments for a given operator is used.

     # File lib/sequel/sql.rb, line 180
180:       def initialize(op, *args)
181:         orig_args = args
182:         args = args.map{|a| Sequel.condition_specifier?(a) ? SQL::BooleanExpression.from_value_pairs(a) : a}
183:         case op
184:         when *N_ARITY_OPERATORS
185:           raise(Error, "The #{op} operator requires at least 1 argument") unless args.length >= 1
186:           old_args = args
187:           args = []
188:           old_args.each{|a| a.is_a?(self.class) && a.op == op ? args.concat(a.args) : args.push(a)}
189:         when *TWO_ARITY_OPERATORS
190:           raise(Error, "The #{op} operator requires precisely 2 arguments") unless args.length == 2
191:           # With IN/NOT IN, even if the second argument is an array of two element arrays,
192:           # don't convert it into a boolean expression, since it's definitely being used
193:           # as a value list.
194:           args[1] = orig_args[1] if IN_OPERATORS.include?(op)
195:         when *ONE_ARITY_OPERATORS
196:           raise(Error, "The #{op} operator requires a single argument") unless args.length == 1
197:         when *CUSTOM_EXPRESSIONS
198:           # nothing
199:         else
200:           raise(Error, "Invalid operator #{op}")
201:         end
202:         @op = op
203:         @args = args
204:       end

Public Instance Methods

sql_boolean() click to toggle source

Return a BooleanExpression with the same op and args.

      # File lib/sequel/sql.rb, line 1017
1017:       def sql_boolean
1018:         BooleanExpression.new(self.op, *self.args)
1019:       end
sql_number() click to toggle source

Return a NumericExpression with the same op and args.

      # File lib/sequel/sql.rb, line 1022
1022:       def sql_number
1023:         NumericExpression.new(self.op, *self.args)
1024:       end
sql_string() click to toggle source

Return a StringExpression with the same op and args.

      # File lib/sequel/sql.rb, line 1027
1027:       def sql_string
1028:         StringExpression.new(self.op, *self.args)
1029:       end

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