mirror of
https://github.com/hasura/graphql-engine.git
synced 2024-12-16 18:42:30 +03:00
147 lines
10 KiB
ReStructuredText
147 lines
10 KiB
ReStructuredText
Hasura GraphQL engine metadata schema
|
|
=====================================
|
|
|
|
.. contents:: Table of contents
|
|
:backlinks: none
|
|
:depth: 2
|
|
:local:
|
|
|
|
Hasura GraphQL engine uses a set of internal tables to manage the state of the database and the
|
|
GraphQL schema. It uses the data in these tables to generate the GraphQL API which then can be accessed
|
|
from different clients.
|
|
|
|
Hasura GraphQL engine when initialized, creates a schema called ``hdb_catalog`` in the Postgres database and
|
|
initializes a few tables under it as described below.
|
|
|
|
**hdb_catalog** schema
|
|
----------------------
|
|
|
|
This schema is created by Hasura GraphQL Engine to manage its internal state. Whenever a
|
|
table/permission/relationship is created/updated using the Hasura console or the metadata API. Hasura GraphQL engine
|
|
captures that information and stores it in the corresponding tables.
|
|
|
|
The following tables are used by Hasura GraphQL engine:
|
|
|
|
**hdb_table** table
|
|
^^^^^^^^^^^^^^^^^^^
|
|
|
|
This table stores information about all the tables/views which are created/tracked using the Hasura console or
|
|
the metadata API.
|
|
|
|
Schema
|
|
""""""
|
|
|
|
.. image:: ../../../img/graphql/manual/engine-internals/hdb_table.jpg
|
|
:scale: 50%
|
|
:alt: hdb_table schema
|
|
|
|
Column Definitions
|
|
""""""""""""""""""
|
|
+---------------------+------------------------------------------------------------------------------------------+
|
|
| column | description |
|
|
+=====================+==========================================================================================+
|
|
| table_schema | Captures information about the schema under which a table/view is tracked |
|
|
+---------------------+------------------------------------------------------------------------------------------+
|
|
| table_name | Captures name of the tracked table/view. |
|
|
+---------------------+------------------------------------------------------------------------------------------+
|
|
| is_system_defined | If it is true, then the table/view is created by GraphQL engine for internal purpose. |
|
|
| | If it is false, then the table/view is created by the end user. |
|
|
+---------------------+------------------------------------------------------------------------------------------+
|
|
|
|
**hdb_relationship** table
|
|
^^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
This table stores information about the relationships created for tables/views using the Hasura console or
|
|
the metadata API.
|
|
|
|
Schema
|
|
""""""
|
|
|
|
.. image:: ../../../img/graphql/manual/engine-internals/hdb_relationship.jpg
|
|
:scale: 50%
|
|
:alt: hdb_relationship schema
|
|
|
|
Column Definitions
|
|
""""""""""""""""""
|
|
|
|
+---------------------+------------------------------------------------------------------------------------------+
|
|
| column | description |
|
|
+=====================+==========================================================================================+
|
|
| table_schema | Captures information about the schema under which a relationship is created. |
|
|
+---------------------+------------------------------------------------------------------------------------------+
|
|
| table_name | Captures name of the table/view under which a relationship is created. |
|
|
+---------------------+------------------------------------------------------------------------------------------+
|
|
| rel_na me | Captures name of the relationship. |
|
|
+---------------------+------------------------------------------------------------------------------------------+
|
|
| rel_type | Captures the permission type (insert/select/update/delete). |
|
|
+---------------------+------------------------------------------------------------------------------------------+
|
|
| perm_def | Captures information about how the relationship is defined. |
|
|
| | |
|
|
| | For example: |
|
|
| | |
|
|
| | .. code-block:: json |
|
|
| | |
|
|
| | { |
|
|
| | "foreign_key_constraint_on": "user_id" |
|
|
| | } |
|
|
+---------------------+------------------------------------------------------------------------------------------+
|
|
| comment | Captures the comment for the relationship. |
|
|
+---------------------+------------------------------------------------------------------------------------------+
|
|
| is_system_defined | If it is true, then the relationship is created by GraphQL engine for internal purpose. |
|
|
| | If it is false, then the relationship is created by the end user. |
|
|
+---------------------+------------------------------------------------------------------------------------------+
|
|
|
|
|
|
**hdb_permission** table
|
|
^^^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
This table stores information about the access control rules on tables/views set up using the Hasura console or
|
|
the metadata API.
|
|
|
|
Schema
|
|
""""""
|
|
|
|
.. image:: ../../../img/graphql/manual/engine-internals/hdb_permission.jpg
|
|
:scale: 50%
|
|
:alt: hdb_permission schema
|
|
|
|
Column Definitions
|
|
""""""""""""""""""
|
|
+---------------------+------------------------------------------------------------------------------------------+
|
|
| column | description |
|
|
+=====================+==========================================================================================+
|
|
| table_schema | Captures information about the schema under which a permission is created. |
|
|
+---------------------+------------------------------------------------------------------------------------------+
|
|
| table_name | Captures name of the table/view under which a permission is created. |
|
|
+---------------------+------------------------------------------------------------------------------------------+
|
|
| role_name | Captures name of the role for which this permission will be applicable. |
|
|
+---------------------+------------------------------------------------------------------------------------------+
|
|
| perm_type | Captures the permission type (insert/select/update/delete). |
|
|
+---------------------+------------------------------------------------------------------------------------------+
|
|
| perm_def | Captures information about how the permission is defined. |
|
|
| | |
|
|
| | Whenever a query is made with the above role for the above table GraphQL engine |
|
|
| | will first validate the requested columns with the columns which the user has access to |
|
|
| | using the ``columns`` key. |
|
|
| | Once the query is validated the appropriate results are returned after applying the |
|
|
| | filter defined in the ``filter`` key. |
|
|
| | |
|
|
| | For example: |
|
|
| | |
|
|
| | .. code-block:: json |
|
|
| | |
|
|
| | { |
|
|
| | "columns": ["id", "name"], |
|
|
| | "filter": { |
|
|
| | "id": { |
|
|
| | "_eq": "X-HASURA-USER-ID" |
|
|
| | } |
|
|
| | } |
|
|
| | } |
|
|
+---------------------+------------------------------------------------------------------------------------------+
|
|
| comment | Captures the comment for the permission. |
|
|
+---------------------+------------------------------------------------------------------------------------------+
|
|
| is_system_defined | If it is true, then the permission is created by GraphQL engine for internal purpose. If |
|
|
| | it is false, then the permission is created by the end user. |
|
|
+---------------------+------------------------------------------------------------------------------------------+
|