rails/rails — pull request #6698 by yahonda (2012-06-11 02:47:48+00:00)
Title: Address ORA-00911 errors because of the heading underscore.

This pull request address errors discussed in be4ecdcc87984e9421ff5d5c90d33f475e0fbc01 for master branch.

```ruby
1) Error:
test_dont_add_if_before_callback_raises_exception(AssociationCallbacksTest):
ActiveRecord::StatementInvalid: OCIError: ORA-00911: invalid character: SELECT 1 AS _one FROM "POSTS" WHERE "POSTS"."AUTHOR_ID" = 1 AND "POSTS"."ID" = 3 AND ROWNUM <= 1
stmt.c:253:in oci8lib_191.so
```

Tested with postgresql, mysql, mysql2 and sqlite3 adapters also.