Class: ROM::SQL::Function
- Inherits:
-
Attribute
- Object
- Attribute
- ROM::SQL::Function
- Includes:
- AttributeWrapping
- Defined in:
- lib/rom/sql/function.rb
Overview
Specialized attribute type for defining SQL functions
Constant Summary collapse
- WINDOW_FRAMES =
This constant is part of a private API. You should avoid using this constant if possible, as it may be removed or be changed in the future.
Hash.new do |cache, frame| type = frame.key?(:rows) ? "ROWS" : "RANGE" bounds = frame[:rows] || frame[:range] cache[frame] = "#{type} BETWEEN #{frame_limit(bounds[0])} AND #{frame_limit(bounds[1])}" end
Class Method Summary collapse
- .frame_limit(value) ⇒ Object private
Instance Method Summary collapse
-
#aliased(alias_name) ⇒ SQL::Function
(also: #as)
Return a new attribute with an alias.
-
#case(mapping) ⇒ ROM::SQL::Attribute
Add a CASE clause for handling if/then logic.
-
#cast(expr, db_type = TypeSerializer[:default].call(type)) ⇒ ROM::SQL::Attribute
Convert an expression result to another data type.
-
#filter(condition = Undefined) {|block| ... } ⇒ SQL::Function
Add a FILTER clause to aggregate function (supported by PostgreSQL 9.4+) Filter aggregate using the specified conditions.
- #is(other) ⇒ Object
- #name ⇒ Object private
- #new(&block) ⇒ Object private
- #not(other) ⇒ Object
-
#over(partition: nil, order: nil, frame: nil) ⇒ SQL::Function
Add an OVER clause making a window function call.
- #qualified(table_alias = nil) ⇒ Object private
- #qualified?(_table_alias = nil) ⇒ Boolean private
- #qualified_projection(table_alias = nil) ⇒ Object private
- #sql_literal(ds) ⇒ Object private
-
#within_group(*args) {|block| ... } ⇒ SQL::Function
Add a WITHIN GROUP clause to aggregate function (supported by PostgreSQL) Establishes an order for an ordered-set aggregate, see the docs for more details.
-
#wrapped(name = source.dataset) ⇒ Attribute
included
from AttributeWrapping
Return attribute type wrapped for the specified relation name.
-
#wrapped? ⇒ Boolean
included
from AttributeWrapping
Return if the attribute type is from a wrapped relation.
Dynamic Method Handling
This class handles dynamic methods through the method_missing method
#method_missing(meth, *args) ⇒ Object (private)
This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.
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# File 'lib/rom/sql/function.rb', line 263 def method_missing(meth, *args) if func if func.respond_to?(meth) (func: func.__send__(meth, *args)) else super end else (func: Sequel::SQL::Function.new(meth.to_s.upcase, *args)) end end |
Class Method Details
.frame_limit(value) ⇒ Object
This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.
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# File 'lib/rom/sql/function.rb', line 16 def frame_limit(value) case value when :current then "CURRENT ROW" when :start then "UNBOUNDED PRECEDING" when :end then "UNBOUNDED FOLLOWING" else if value.positive? "#{value} FOLLOWING" else "#{value.abs} PRECEDING" end end end |
Instance Method Details
#aliased(alias_name) ⇒ SQL::Function Also known as: as
Return a new attribute with an alias
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# File 'lib/rom/sql/function.rb', line 54 def aliased(alias_name) super.with(name: name || alias_name) end |
#case(mapping) ⇒ ROM::SQL::Attribute
Add a CASE clause for handling if/then logic. This version of CASE search for the first
branch which evaluates to true
. See SQL::Attriubte#case if you're looking for the
version that matches an expression result
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# File 'lib/rom/sql/function.rb', line 191 def case(mapping) mapping = mapping.dup otherwise = mapping.delete(:else) do raise ArgumentError, "provide the default case using the :else keyword" end Attribute[type].(sql_expr: ::Sequel.case(mapping, otherwise)) end |
#cast(expr, db_type = TypeSerializer[:default].call(type)) ⇒ ROM::SQL::Attribute
Convert an expression result to another data type
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# File 'lib/rom/sql/function.rb', line 176 def cast(expr, db_type = TypeSerializer[:default].call(type)) Attribute[type].(sql_expr: ::Sequel.cast(expr, db_type)) end |
#filter(condition = Undefined) {|block| ... } ⇒ SQL::Function
Add a FILTER clause to aggregate function (supported by PostgreSQL 9.4+) Filter aggregate using the specified conditions
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# File 'lib/rom/sql/function.rb', line 215 def filter(condition = Undefined, &block) if block conditions = schema.restriction(&block) conditions &= condition unless condition.equal?(Undefined) else conditions = condition end super(conditions) end |
#is(other) ⇒ Object
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# File 'lib/rom/sql/function.rb', line 111 def is(other) ::ROM::SQL::Attribute[::ROM::SQL::Types::Bool].( sql_expr: ::Sequel::SQL::BooleanExpression.new(:"=", func, other) ) end |
#name ⇒ Object
This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.
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# File 'lib/rom/sql/function.rb', line 69 def name self.alias || super end |
#new(&block) ⇒ Object
This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.
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# File 'lib/rom/sql/function.rb', line 92 def new(&block) case func when ::Sequel::SQL::Function (func: ::Sequel::SQL::Function.new!(func.name, func.args.map(&block), func.opts)) else (func: func) end end |
#not(other) ⇒ Object
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# File 'lib/rom/sql/function.rb', line 120 def not(other) !is(other) end |
#over(partition: nil, order: nil, frame: nil) ⇒ SQL::Function
Add an OVER clause making a window function call
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# File 'lib/rom/sql/function.rb', line 160 def over(partition: nil, order: nil, frame: nil) super(partition: partition, order: order, frame: WINDOW_FRAMES[frame]) end |
#qualified(table_alias = nil) ⇒ Object
This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.
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# File 'lib/rom/sql/function.rb', line 76 def qualified(table_alias = nil) new { |arg| arg.respond_to?(:qualified) ? arg.qualified(table_alias) : arg } end |
#qualified?(_table_alias = nil) ⇒ Boolean
This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.
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# File 'lib/rom/sql/function.rb', line 104 def qualified?(_table_alias = nil) [:func].args.all?(&:qualified?) end |
#qualified_projection(table_alias = nil) ⇒ Object
This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.
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# File 'lib/rom/sql/function.rb', line 85 def qualified_projection(table_alias = nil) new { |arg| arg.respond_to?(:qualified_projection) ? arg.qualified_projection(table_alias) : arg } end |
#sql_literal(ds) ⇒ Object
This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.
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# File 'lib/rom/sql/function.rb', line 60 def sql_literal(ds) if name ds.literal(func.as(name)) else ds.literal(func) end end |
#within_group(*args) {|block| ... } ⇒ SQL::Function
Add a WITHIN GROUP clause to aggregate function (supported by PostgreSQL) Establishes an order for an ordered-set aggregate, see the docs for more details
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# File 'lib/rom/sql/function.rb', line 240 def within_group(*args, &block) if block group = args + ::ROM::SQL::OrderDSL.new(schema).(&block) else group = args end super(*group) end |
#wrapped(name = source.dataset) ⇒ Attribute Originally defined in module AttributeWrapping
Return attribute type wrapped for the specified relation name
#wrapped? ⇒ Boolean Originally defined in module AttributeWrapping
Return if the attribute type is from a wrapped relation
Wrapped attributes are used when two schemas from different relations are merged together. This way we can identify them easily and handle correctly in places like auto-mapping.