New Features

• Support for property graphs has been added on PostgreSQL 19+. This includes support for creating, altering, and dropping property graphs:

  DB.create_property_graph(:g) do
    vertex :people
    vertex :companies
  
    edge :employment do
      source :people
      destination :companies
    end
  end
  # CREATE PROPERTY GRAPH g
  #   VERTEX TABLES (people, companies)
  #   EDGE TABLES (employment SOURCE people DESTINATION companies)
  
  DB.alter_property_graph(:g) do
    add_vertex :v
  end
  # ALTER PROPERTY GRAPH g ADD VERTEX TABLES (v)
  
  DB.rename_property_graph(:g, :g2)
  # ALTER PROPERTY GRAPH g RENAME TO g2
  
  DB.set_property_graph_schema(:g2, :other_schema, if_exists: true)
  # ALTER PROPERTY GRAPH IF EXISTS g2 SET SCHEMA other_schema
  
  DB.drop_property_graph(:g)
  # DROP PROPERTY GRAPH g
  

  Listing property graphs:

  DB.property_graphs
  # => [:property_graph_name_1, :property_graph_name_2]
  

  As well as using GRAPH_TABLE in queries:

  gt = DB.graph_table(:graph, :companies, var: :c).
    from(:works_at, var: :w).
    link(:people, var: :p, where: {Sequel[:p][:name] => 'Alice'}).
    columns(Sequel[:p][:name].as(:person_name), Sequel[:w][:role].as(:role))
  DB.from(gt).sql
  # SELECT * FROM GRAPH_TABLE (graph
  #   MATCH (c IS companies)<-[w IS works_at]-(p IS people WHERE (p.name = 'Alice'))
  #   COLUMNS (p.name AS person_name, w.role AS role))
  

• On SQLite, Dataset#explain now accepts a :query_plan option to use EXPLAIN QUERY PLAN, which results in more user-friendly output.