Enterprise Database Server initial values (global defaults or local specifications) cause an anomaly from the SQL viewpoint when applied to occurring items. Relational Design Center creates a new embedded table for each occurring item. When a Enterprise Database Server record is created and an occurring item has an initial value specification or inherits an initial value from a global default initial value, all occurrences of the item are initialized to the same value. Therefore, a maximum number of occurring rows are created when the master row is created. In addition, all the rows are automatically deleted when the master row is deleted.

Inserting a New Row

The anomaly appears when you attempt to insert a new row into one of these embedded tables after the master row is created. You must first delete a row of the embedded table before attempting to insert a new occurring row. If you fail to delete the applicable row, the number of rows exceeds the maximum number allowed. Exceeding the maximum limit causes the program to receive an exception and the insertion fails.

If no global default initial value and no local initial value for an occurring item exist, then the embedded table rows are not created and this anomaly does not occur.

Enterprise Database Server Boolean items, field items, and field bit items cannot have null values. The system assigns default initial values to these items. (For a table of default initial values, refer to the Data and Structure Definition Language (DASDL) Programming Reference Manual.) Once the master row is created, all the occurring item rows that are themselves one of these types, or that contain one of these types, are also created. In addition, these rows can be deleted only by deleting their master row.