= 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.
