SQL/MP Installation and Management Guide

The SQL/MP Database Management Environment
HP NonStop SQL/MP Installation and Management Guide—523353-004
1-6
Data Integrity
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File recovery, which reconstructs specific audited files when the current copies on
the data volume are not usable; for example, if a system or media failure
jeopardizes the consistency of one or more audited files
The BACKUP utility provides volume-mode and file-mode tape backups for database
objects and for SQL programs stored in Guardian files, which you can recover with
RESTORE. Volume-mode backup makes a physical copy of a disk volume on tape.
File-mode backup copies each SQL object or file in a file set list to tape.
You can also save database creation and loading scripts in OBEY command files or
write an automated program to handle TMF and backup and restore operations.
OSS utilities provide backup functionality for SQL programs stored in OSS files.
For more information about database protection and recovery, see The TMF
Subsystem on page 4-10 and Restoring Objects With TMF Recovery Operations on
page 11-11.
Data Integrity
The database management system protects the database by ensuring that entered
data meets the definitional requirements. Application programs, therefore, do not need
to perform data checking.
These data definition features ensure definitional integrity:
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Column definitions
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Protection views
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Constraints
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Indexes
These features provide additional data integrity for SQL/MP databases:
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Database changes are monitored by the TMF subsystem.
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Database access is restricted to SQL statements.
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Integrity constraints on tables are enforced by the disk process.
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Database consistency is maintained by concurrency control.
The TMF subsystem provides data integrity. Database updates performed as part of a
TMF transaction are either all committed to the database when the transaction
completes or all backed out if the transaction does not complete. With the TMF two-
phase commit protocol, an update changes a database from one consistent state to
another; an incomplete transaction does not change the database. TMF transactions
can be distributed across multiple nodes.
Database access is restricted to standard Data Manipulation Language (DML), Data
Definition Language (DDL), Data Control Language (DCL), and Data Status Language
(DSL) statements. No exit routines can inadvertently corrupt a database.