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-rw-r--r--guides/source/migrations.md6
1 files changed, 5 insertions, 1 deletions
diff --git a/guides/source/migrations.md b/guides/source/migrations.md
index 89ae564c24..bd63970bea 100644
--- a/guides/source/migrations.md
+++ b/guides/source/migrations.md
@@ -61,6 +61,10 @@ migrations are wrapped in a transaction. If the database does not support this
then when a migration fails the parts of it that succeeded will not be rolled
back. You will have to rollback the changes that were made by hand.
+NOTE: There are certain queries that can't run inside a transaction. If your
+adapter supports DDL transactions you can use `disable_ddl_transaction!` to
+disable them for a single migration.
+
If you wish for a migration to do something that Active Record doesn't know how
to reverse, you can use `reversible`:
@@ -180,7 +184,7 @@ end
```
If the migration name is of the form "CreateXXX" and is
-followed by a list of column names and types then a migration creating the table
+followed by a list of column names and types then a migration creating the table
XXX with the columns listed will be generated. For example:
```bash