AgensGraph 2.18
===============

AgensGraph is a multi-model database built on PostgreSQL. It stores your data as a
**property graph** and as relational tables at the same time. You query that data in
**Cypher**, in **GQL** (ISO/IEC 39075), or in **SQL**, and you can combine two of them in one
statement when that is the shortest way to the answer.

Release 2.18 is built on PostgreSQL 18 and adds a substantial part of the GQL standard.
:doc:`release_notes/2.18` lists what changed, including the changes your application needs to
know about.

How this manual is organized
----------------------------

:doc:`get_started/index` installs the server, loads the small film graph that every example
in this manual uses, and gets you to a result. Read it first.

:doc:`concepts/index` explains the property-graph model, and how a graph is laid out in
PostgreSQL. A graph is a schema and a label is a table. That is what lets one statement mix
graph and relational work.

:doc:`querying/index` teaches the language in the order you meet it: reading, writing,
composing pipelines, walking paths, indexing, and crossing between SQL and Cypher.

:doc:`reference/index` is the formal definition of the same language — the lexical rules,
the types, and a page for each clause, statement and function. Look here when you know what
you want and need the exact syntax.

:doc:`guides/index` covers loading data and the search features. :doc:`drivers/index` points
at the client libraries. :doc:`operations/index` is for running a server.
:doc:`system_catalogs/index` documents the catalogs that describe a graph, and
:doc:`appendix/index` holds the GQL conformance tables, the compatibility notes, the
keyword and error-code lists, and a map from the 2.17 page names to these.

Where to go next
----------------

.. grid:: 1 2 2 3
   :gutter: 3

   .. grid-item-card:: Get Started
      :link: get_started/index
      :link-type: doc

      Install AgensGraph, load the example graph, run your first query.

   .. grid-item-card:: Concepts
      :link: concepts/index
      :link-type: doc

      The property-graph model, and how a graph is stored in PostgreSQL.

   .. grid-item-card:: Querying
      :link: querying/index
      :link-type: doc

      Reading, writing, paths, indexes, and mixing SQL with Cypher.

   .. grid-item-card:: Reference
      :link: reference/index
      :link-type: doc

      Clauses, data definition, functions, types, and settings.

   .. grid-item-card:: Guides
      :link: guides/index
      :link-type: doc

      Loading data, vector, full-text and hybrid search, and the AI integrations.

   .. grid-item-card:: Drivers
      :link: drivers/index
      :link-type: doc

      Any PostgreSQL driver connects, and the Python driver adds the graph types.

   .. grid-item-card:: Operations
      :link: operations/index
      :link-type: doc

      Deploy, configure, secure and back up a server.

   .. grid-item-card:: System Catalogs
      :link: system_catalogs/index
      :link-type: doc

      The catalogs and views that describe a graph.

   .. grid-item-card:: Release Notes
      :link: release_notes/index
      :link-type: doc

      What changed in 2.18, and how to upgrade to it.

.. toctree::
   :hidden:

   get_started/index
   concepts/index
   querying/index
   reference/index
   guides/index
   drivers/index
   operations/index
   system_catalogs/index
   release_notes/index
   appendix/index