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Diffstat (limited to 'doc/development/migration_style_guide.md')
| -rw-r--r-- | doc/development/migration_style_guide.md | 27 |
1 files changed, 23 insertions, 4 deletions
diff --git a/doc/development/migration_style_guide.md b/doc/development/migration_style_guide.md index 4cf546173de..7d3d9dac174 100644 --- a/doc/development/migration_style_guide.md +++ b/doc/development/migration_style_guide.md @@ -35,7 +35,7 @@ and post-deployment migrations (`db/post_migrate`) are run after the deployment ## Schema Changes -Changes to the schema should be commited to `db/structure.sql`. This +Changes to the schema should be committed to `db/structure.sql`. This file is automatically generated by Rails, so you normally should not edit this file by hand. If your migration is adding a column to a table, that column will be added at the bottom. Please do not reorder @@ -49,7 +49,7 @@ regenerate a clean `db/structure.sql` for the migrations you're adding. This script will apply all migrations found in `db/migrate` or `db/post_migrate`, so if there are any migrations you don't want to commit to the schema, rename or remove them. If your branch is not -targetting `master` you can set the `TARGET` environment variable. +targeting `master` you can set the `TARGET` environment variable. ```shell # Regenerate schema against `master` @@ -343,7 +343,7 @@ def up end ``` -The RuboCop rule generally allows standard Rails migration methods, listed below. This example will cause a rubocop offense: +The RuboCop rule generally allows standard Rails migration methods, listed below. This example will cause a Rubocop offense: ```ruby disabled_ddl_transaction! @@ -367,6 +367,8 @@ migration involves one of the high-traffic tables: - `users` - `projects` - `namespaces` +- `issues` +- `merge_requests` - `ci_pipelines` - `ci_builds` - `notes` @@ -550,6 +552,12 @@ operations that don't require `disable_ddl_transaction!`. You can read more about adding [foreign key constraints to an existing column](database/add_foreign_key_to_existing_column.md). +## `NOT NULL` constraints + +> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/38358) in GitLab 13.0. + +See the style guide on [`NOT NULL` constraints](database/not_null_constraints.md) for more information. + ## Adding Columns With Default Values With PostgreSQL 11 being the minimum version since GitLab 13.0, adding columns with default values has become much easier and @@ -559,6 +567,11 @@ Before PostgreSQL 11, adding a column with a default was problematic as it would have caused a full table rewrite. The corresponding helper `add_column_with_default` has been deprecated and will be removed in a later release. +NOTE: **Note:** +If a backport adding a column with a default value is needed for %12.9 or earlier versions, +it should use `add_column_with_default` helper. If a [large table](https://gitlab.com/gitlab-org/gitlab/-/blob/master/rubocop/rubocop-migrations.yml#L3) +is involved, backporting to %12.9 is contraindicated. + ## Changing the column default One might think that changing a default column with `change_column_default` is an @@ -611,7 +624,7 @@ end ``` If a computed update is needed, the value can be wrapped in `Arel.sql`, so Arel -treats it as an SQL literal. It's also a required deprecation for [Rails 6](https://gitlab.com/gitlab-org/gitlab/issues/28497). +treats it as an SQL literal. It's also a required deprecation for [Rails 6](https://gitlab.com/gitlab-org/gitlab/-/issues/28497). The below example is the same as the one above, but the value is set to the product of the `bar` and `baz` columns: @@ -727,6 +740,12 @@ Rails migration example: add_column(:projects, :foo, :integer, default: 10, limit: 8) ``` +## Strings and the Text data type + +> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/30453) in GitLab 13.0. + +See the [text data type](database/strings_and_the_text_data_type.md) style guide for more information. + ## Timestamp column type By default, Rails uses the `timestamp` data type that stores timestamp data |