diff options
Diffstat (limited to 'guides')
| -rw-r--r-- | guides/source/active_record_migrations.md | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/guides/source/active_record_migrations.md b/guides/source/active_record_migrations.md index cfa444fda0..be5af133ff 100644 --- a/guides/source/active_record_migrations.md +++ b/guides/source/active_record_migrations.md @@ -491,6 +491,10 @@ NOTE: Active Record only supports single column foreign keys. `execute` and `structure.sql` are required to use composite foreign keys. See [Schema Dumping and You](#schema-dumping-and-you). +NOTE: At this time, only the mysql, mysql2 and postgresql adapters support +foreign keys. Implementation for sqlite3 is partial, keys are created for new +tables but not for existing tables via `ALTER TABLE` statement. + Removing a foreign key is easy as well: ```ruby |