First, you must encrypt the backend/source database. Then you need to reestablish the linked tables in the frontend database.
Here's how to encrypt the backend.
About The "Row Level Locking" Message
A block cipher is a method of encrypting text in which a cryptographic key and algorithm are applied to a whole block of data at once, rather than to each bit at a time.
Row level locking (or record level locking) is where a record is locked whenever it is updated. This is to prevent other users from accessing data being while it is being updated.
When you update a record in an encrypted database that uses row level locking, only the record (row) is encrypted, not the whole database.
When you encrypt a database with row level locking disabled, you will receive the Encrypting with block cipher is incompatible with row level locking. Row level locking will be ignored. message.
What this means is that the whole database will be encrypted — not just the record.
Update the Frontend
Once you've encrypted the backend database, you now need to unlink, then relink the tables that point to the backend.
Unlink the Tables
Here's how to unlink the linked tables.
Relink the Tables
Now we can relink those tables (and provide the password when we do so).