Class: Sequel::Postgres::PropertyGraph::Generator::AlterElement

Inherits:
Sequel::Postgres::PropertyGraph::Generator show all
Defined in:
lib/sequel/adapters/shared/postgres.rb

Overview

AlterElement is used to evaluate the block passed to Alter#alter_vertex_table and Alter#alter_edge_table.

Constant Summary

Constants inherited from Sequel::Postgres::PropertyGraph::Generator

Vertex

Instance Method Summary collapse

Methods inherited from Sequel::Postgres::PropertyGraph::Generator

new

Constructor Details

#initialize(kind, name, &block) ⇒ AlterElement

kind is :vertex or :edge. name is the alias of the vertex or edge table to alter.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 456

def initialize(kind, name, &block)
  @kind = kind
  @name = name
  @labels = []
  @operations = []
  instance_exec(&block)

  # All labels added via #add_label are combined into a single
  # ADD LABEL operation, as PostgreSQL supports adding multiple
  # labels in a single ALTER ... ADD LABEL statement.
  unless @labels.empty?
    @operations << {:op=>:add_label, :kind=>kind, :name=>name, :labels=>@labels.freeze}
  end

  @operations.each(&:freeze)
  @operations.freeze
  freeze
end

Instance Method Details

#add_label(name, properties = :all) ⇒ Object

Add a label (and optional properties) to the vertex/edge table. Takes the same arguments as Element#label. Can be called multiple times to add multiple labels.

add_label(:l)
# ADD LABEL l PROPERTIES ALL COLUMNS


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# File 'lib/sequel/adapters/shared/postgres.rb', line 485

def add_label(name, properties=:all)
  @labels << [name, properties].freeze
  nil
end

#add_properties(label, properties) ⇒ Object

Add properties to an existing label on the vertex/edge table. properties is an expression, or array of expressions, the same as the explicit array form of the properties argument to Element#label.

add_properties(:l, [:c1, Sequel[:c2].as(:c3)])
# ALTER LABEL l ADD PROPERTIES (c1, c2 AS c3)


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# File 'lib/sequel/adapters/shared/postgres.rb', line 507

def add_properties(label, properties)
  @operations << {:op=>:add_properties, :kind=>@kind, :name=>@name, :label=>label, :properties=>Array(properties)}
  nil
end

#data ⇒ Object 



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# File 'lib/sequel/adapters/shared/postgres.rb', line 475

def data
  @operations
end

#drop_label(name, opts = OPTS) ⇒ Object

Remove a label from the vertex/edge table. Options: :cascade :: Use CASCADE to drop dependent objects.

drop_label(:l)
# DROP LABEL l


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# File 'lib/sequel/adapters/shared/postgres.rb', line 495

def drop_label(name, opts=OPTS)
  @operations << {:op=>:drop_label, :kind=>@kind, :name=>@name, :label=>name, :cascade=>opts[:cascade]}
  nil
end

#drop_properties(label, properties, opts = OPTS) ⇒ Object

Remove properties from an existing label on the vertex/edge table. properties is a column name, or array of column names. Options: :cascade :: Use CASCADE to drop dependent objects.

drop_properties(:l, [:c1])
# ALTER LABEL l DROP PROPERTIES (c1)


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# File 'lib/sequel/adapters/shared/postgres.rb', line 518

def drop_properties(label, properties, opts=OPTS)
  @operations << {:op=>:drop_properties, :kind=>@kind, :name=>@name, :label=>label, :properties=>Array(properties), :cascade=>opts[:cascade]}
  nil
end