A primary key is an object field (a column in a database table or a database view) or a set of object fields (columns in a database) that can uniquely identify each record in a database table or database view. You use primary keys to query objects in the database.

If an entity does not have a primary key, you can define a custom composite key for the entity. To create a custom composite key, manually select a field or multiple fields for that key. The custom composite key takes the place of the primary key, and you can use it to read data from a JDBC database.

Example: You connect to a JDBC database of employee records and you see that the entity

empaccount

does not have a primary key. You can manually select the fields

email

,

ID

, and

name

to define a custom composite key for

empaccount

.

You can also edit custom composite keys that you created. If you defined a custom composite key that references an entity that no longer exists, you can remove the key. If a custom key contains fields that no longer exist, you can remove these fields.