Introduction to Navigational Programming › Retrieving Data

Retrieving Data

Using navigational DML, you access database records one record at a time using retrieval functions to locate record occurrences and return their contents.

There are several ways of retrieving data using navigational DML. For example, an application program can retrieve every record occurrence in an area or it can retrieve records that participate in a set occurrence or that have a specific key value.

Many retrieval operations rely on an application's current position within the database, that is, its most recently accessed record. For example, when retrieving the next EMPLOYEE record occurrence within an area, the DBMS bases the operation on the EMPLOYEE record occurrence last accessed. This notion of currency is described in the next section followed by a description of the types of retrieval functions that are available and how they are used to access data.