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Diffstat (limited to 'guides/source')
| -rw-r--r-- | guides/source/active_record_migrations.md | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/guides/source/active_record_migrations.md b/guides/source/active_record_migrations.md index b89485b945..c111996b58 100644 --- a/guides/source/active_record_migrations.md +++ b/guides/source/active_record_migrations.md @@ -355,6 +355,13 @@ end will append `ENGINE=BLACKHOLE` to the SQL statement used to create the table (when using MySQL or MariaDB, the default is `ENGINE=InnoDB`). +Also you can pass the `:comment` option with any description for the table +that will be stored in database itself and can be viewed with database administration +tools, such as MySQL Workbench or PgAdmin III. It's highly recommended to specify +comments in migrations for applications with large databases as it helps people +to understand data model and generate documentation. +Currently only MySQL and PostgreSQL supports comments. + ### Creating a Join Table The migration method `create_join_table` creates an HABTM (has and belongs to @@ -454,6 +461,7 @@ number of digits after the decimal point. are using a dynamic value (such as a date), the default will only be calculated the first time (i.e. on the date the migration is applied). * `index` Adds an index for the column. +* `comment` Adds a comment for the column. Some adapters may support additional options; see the adapter specific API docs for further information. |