2 Introduction
| Manual | Automatic |
|---|---|
| May stand alone. Need not be related to any detail data set. | Must be related to one or more detail data sets. |
| May contain data items in addition to the search item. | Must contain only one data item, the search item. |
| Entries must be explicitly added or deleted. A related detail data entry cannot be added until a master entry with a matching search item value has been added. When the last detail entry related to a master is deleted, the master entry still remains in the data set. Before a master entry can be deleted all related detail entries must be deleted. | Eloquence DBMS automatically adds or deletes entries when needed based on the addition or deletion of related detail data set entries. When a detail entry is added with a search item value different from all current search item values, a master entry with matching search item value is automatically added. Deletions of detail entries trigger an automatic deletion of the matching master entry if it is determined that all related data chains are empty. |
| The search item values of existing master entries serve as a table of legitimate search item values for all related detail data sets. Thus, a manual master can be used to prevent the entry of invalid data in the related data sets. |