Database ID

The database ID uniquely identifies the data area of a database instance. The database system creates the database ID during the creation of a new database instance according to the following pattern:

<computer_name>:<database_name>_<date>_<time>

The database ID of the data area of database instance DEMODB on the PARMA computer, which was created on 01/30/2006 at 11:26:33.

PARMA:DEMODB_20060130_112633

The database system needs the database ID to see whether the backups really belong to the database instance when it restores the database instance.

The database ID of the data area changes in the following situations:

?     You have initialized the database instance and then restored it from data backup.

The data area of the database instance contains the database ID that was stored in the backup.

When you import a backup into another database instance (for example when creating a database copy), the database ID first receives the name of the backed-up database instance.

When you create the first backup of the restored database instance, the data area is given a new database ID containing the name of the current database instance and the current time stamp.

?     You have carried out a data backup after a gap in the backup history occurred (for example after the restart of the database instance up to a certain time, or after the overwrite mode for the log area was switched on).

The data area of the database instance contains a new database ID with the current time stamp.

The database system stores the database ID to the following locations:

?     The restart record in the data area (identifies the data area of the database instance)

?     The information page of the log area (identifies the log area of the database instance)

?     The information page of each backup (identifies the backup)

In the following cases the database ID of data area and log area do not match:

?     You have imported a database backup from another database instance without initializing the database instance (and thereby emptying the log area).

?     In hot standby systems (multiple database instances use the same log area)

See also:

Database Manager CLI,

db_restartinfo

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