Class: Sequel::Postgres::PropertyGraph::Generator::Element

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

Overview

Base class for Vertex and Edge.

Direct Known Subclasses

Edge

Defined Under Namespace

Classes: Data

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(name, opts = OPTS, &block) ⇒ Element

name specifies the name of the vertex or edge. It can be an SQL::AliasedExpression to use an alias. Options: :properties :: Specifies fixed properties for the vertex or edge. If this is given, you cannot use the label method inside the block.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 284

def initialize(name, opts=OPTS, &block)
  @name = name
  @labels = []
  if opts.key?(:properties)
    @labels << [nil, opts[:properties]].freeze
    @labels.freeze
  end
  instance_exec(&block) if block
  @labels.freeze
  freeze
end

Instance Method Details

#data ⇒ Object 



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# File 'lib/sequel/adapters/shared/postgres.rb', line 296

def data
  Data.new(@name, @key, @labels).freeze
end

#key(columns) ⇒ Object

Set the column(s) to use for the KEY clause, which are the columns that uniquely identify rows in the table:

key(:id)
# KEY (id)

key([:id1, :id2])
# KEY (id1, id2)


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# File 'lib/sequel/adapters/shared/postgres.rb', line 308

def key(columns)
  @key = Array(columns)
end

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

Add a label and properties for the label for this vertex/edge.
A vertex or edge can have multiple labels with separate properties, if it wasn't created with fixed properties. The name argument specifies the label name. The properties argument specifies the properties: nil, :all :: PROPERTIES ALL COLUMNS false, :none, [] :: NO PROPERTIES

Array

Array of specific properties. Each element should be a Symbol, SQL::Identifier, or SQL::AliasedExpression.

label(:label_name)

LABEL label_name PROPERTIES ALL COLUMNS

label(:label_name, [])
# LABEL label_name NO PROPERTIES

label(:label_name, [:c, Sequel[:b].as(:d)], Sequel[:e])
# LABEL label_name PROPERTIES (c, b AS d, e)


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# File 'lib/sequel/adapters/shared/postgres.rb', line 330

def label(name, properties=:all)
  if @labels.frozen?
    raise Error, "cannot specify label for property graph vertex or edge with fixed properties"
  end
  @labels << [name, properties].freeze
  nil
end