Database Reference
In-Depth Information
To further reinforce the security mechanism of the database, more sophisticated
products provide the facility to encrypt data stored in database files. In other products,
the conventional wisdom is to rely on the encryption feature provided by the underlying
operating system.
21.3 Database Management
As mentioned in Chapter 11, once the database has been created, it must be populated
with database objects. Database objects include tablespaces (specific to Oracle), tables,
indexes, views, synonyms, procedures, triggers, packages, sequences, users, roles, etc.
Most of these database objects are dynamic and will grow or shrink in size, with the
passing of time. The database and its objects must therefore be managed.
Database management is a complex matter that covers a wide range of activities;
among these are the following:
•
Reorganizing existing database tables and indexes
•
Deleting unnecessary indexes or moving other objects
•
Making alterations to the database itself
•
Making alterations to database components (tablespaces,
datafiles, tables, procedures, etc.)
•
Creating additional database objects (tablespaces, datafiles,
tables, users, indexes, procedures, etc.)
•
Training users
•
Backup and recovery of database objects
•
Database performance tuning
Most of these issues have been discussed in previous chapters. The last two issues —
backup and recovery, and database performance tuning — deserve some attention. They
will be addressed in the next two sections.
21.4 Database Backup and Recovery
In general, the term database backup and recovery refers to the various strategies and
procedures involved in protecting a database against data loss, and reconstructing
the data should that loss occur. The reconstructing of data is achieved through media
recovery, which refers to the various operations involved in restoring, rolling forward,
and rolling back a backup of database files. Like database installation, creation and
configuration, backup and recovery can be quite simple or very complex, depending on
the database environment, and the desired objectives. For the remainder of this section,
we shall consider, as case study, backup and recovery in the Oracle environment (it does
not get any more complicated than this).
