10.7 Mapping Multivalue Attributes to Single-Value Database Fields

By default, the driver assumes that all eDirectory attributes mapped to parent table columns or view columns have a single value. Because the driver is unaware of the eDirectory schema, it has no way of knowing whether an eDirectory attribute has a single value or has multiple values. Accordingly, multivalue and single-value attribute mappings are handled identically.

The driver implements the Most Recently Touched (MRT) algorithm with regard to single-value parent table or view columns. An MRT algorithm ensures that the most recently added attribute value or most recently deleted attribute value is stored in the database. The algorithm is adequate if the attribute in question has a single value.

If the attribute has multiple values, the algorithm has some undesirable consequences. When a value is deleted from a multivalue attribute, the database field it is mapped to is set to NULL and remains NULL until another value is added. The preferred solution to this undesirable behavior is to extend the eDirectory schema so that only single-value attributes are mapping to parent table or view columns.

Other solutions include the following: