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86 lines
2.4 KiB
ReStructuredText
86 lines
2.4 KiB
ReStructuredText
.. meta::
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:description: Hasura Migration file format reference
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:keywords: hasura, docs, migration, file format
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.. _migration_file_format_v1:
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Migration file format reference (config v1)
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===========================================
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.. contents:: Table of contents
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:backlinks: none
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:depth: 1
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:local:
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Migration filename format
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-------------------------
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Each migration file has the following format:
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.. code-block:: bash
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<version>_<name>.{up|down}.{sql|yaml}
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A ``version`` which is the Unix timestamp in nanoseconds when the file was
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created is the first part. Followed by a ``name`` which is either manually added
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or auto-generated by the console. The next part indicates what step this is. If
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it is ``up``, it means that this is the forward step, for e.g. creating a
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relationship or a table. The ``down`` indicates that it is the corresponding
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rollback step. The last part denotes the file format - whether it is an SQL file
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or a YAML file.
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YAML files
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----------
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Each ``up`` or ``down`` YAML file contains Hasura metadata API actions to be
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executed for that particular migration. The file should have a list of such API
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actions, which is represented with a ``-`` in YAML. Here is an example file:
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**1551151778747_create_table_public_author.up.yaml**
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.. code-block:: yaml
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- type: run_sql
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args:
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sql: |
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CREATE TABLE "public"."author" (
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"id" SERIAL NOT NULL,
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"name" TEXT NOT NULL,
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PRIMARY KEY ("id")
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);
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- type: track_table
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args:
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schema: public
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name: author
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**1551151778747_create_table_public_author.down.yaml**
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.. code-block:: yaml
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- type: untrack_table
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args:
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schema: public
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name: author
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- type: run_sql
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args:
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sql: |
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DROP TABLE "public"."author"
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Each one of the actions in these files are actually Hasura metadata API calls,
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which are executed in **sequence** when the migration is applied. You can find
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all the metadata actions that are available in the :ref:`API reference <Query>`.
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SQL Files
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---------
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.. note::
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The files are there just for the user's convenience, since the SQL can
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already be included in the YAML files.
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As the name indicates, an SQL file can contain SQL statements which are executed
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on the apply step of the migration. There can be an ``up`` SQL and a ``down``
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SQL file. The SQL file is executed first if it is present in an up migration and the
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YAML file is executed first in a down migration.
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