User-defined Keys

There are a number of places in AQT where you need to specify a unique key for your table/view. For instance:

• when editing a table using inline edit
• when updating / delete rows using row update / delete
• using the Data Compare
• when using Update Mode with the Data Loader

In all these cases, AQT will try to automatically determine the unique keys for the table. It does this by:

• if the table has a Primary Key, AQT will use these key columns
• if your table has a Unique Index, AQT will use the keys of this index. If your table has multiple unique indexes, the first index that AQT finds will be used.

If your table has neither a primary key nor a unique index, AQT will prompt you for the columns that comprise the unique key of the table. After you have selected these, AQT will then ask you whether you want AQT to remember this key. If so, AQT will create a user-defined key for the table/view.

AQT will use that key when you are using that table in the future; this saves having to specify the key columns every time.

User-defined keys are particularly useful if you are dealing views, since primary keys and unique indexes cannot be defined on views.

Other notes:

• User-defined are keys are used only by AQT. No changes are made to the database when you define a user-defined key.
• AQT will not check that the key is actually unique before you define it as a user-defined key. It is your responsibility to ensure that the key specified is unique.
• AQT checks the user-defined keys before seeing if there is a primary key or unique key defined on the table. You may wish to define user-defined keys for the tables you deal with on a frequent basis - this will avoid the overhead of AQT having to access the database to check for primary key / unique key.

Editing your list of User-Defined Keys

To see the user-defined keys that have been defined for your database:

• from the Database Explorer, go Tools > Edit list of Unique Keys
• from the Data Display window, go Edit Data > Edit list of Unique Keys

User-defined keys are held in file key<dbname>.txt (example keyAQTDemo.txt) in your default directory. The file name is given in the caption on the User-Defined Keys window.

You can manipulate these files like normal files - edit, copy between machines etc.