At least one simple attribute in each business object must be specified as the key. To define an attribute as a key, set this property to Yes. If the business object attribute is of type String, it is recommended that the data type in the database is of type Varchar instead of char.
If the key property is set to true for a simple attribute, the connector adds that attribute to the WHERE clause of SELECT, UPDATE, RETRIEVE, and DELETE SQL statements that it generates while processing the business object.
If the key property is set to true for an attribute in a child that stores the parent/child relationship in the child (both multiple-cardinality and single-cardinality), the connector uses the parent's primary keys in the WHERE clause of the SELECT statement, and it does not use the Key property. For information on specifying the name of business object attributes whose values are used to set the child's foreign-key attributes, see Application-specific information at the attribute level.