iX V6.5 (30391-90011)

Chapter 4 131

Using the Database

Closing the Database or a Data Set

After you have completed all the tasks with the database, use the DBCLOSE library

procedure to terminate access to the database. When DBCLOSE is used for this purpose, all

data sets and the root ﬁle are closed, and the DBU control block is released to the MPE/iX

system. If there are no other concurrent users of the database, the DBB and DBG control

blocks are also released. All locks that you could still have on the database through the

closed access path are automatically released.

The DBCLOSE procedure can also be used to rewind or close access to a data set. Rewinding

consists of resetting to its initial state the dynamic status information kept by

TurboIMAGE/XL. If a detail data set is closed or rewound, the current path does not

change when the status information is initialized.

The purpose of closing a data set completely is to return the resources required by that

data set to the MPE/iX system without terminating access to the database. A typical

reason for rewinding a data set is to start at the ﬁrst or last entry again when doing a

forward or backward serial read.