SQL/MX 3.2.1 Management Manual (H06.26+, J06.15+)

multiple sites into one central site. For more information, see the RDF/IMP, IMPX, and ZLT
System Management Manual.
• The Guardian Backup and Restore 2 utility, which you can use to perform tape backups and
restore SQL/MX objects. 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.
Use Backup and Restore 2 to back up to tape and restore to disk SQL/MX objects, OSS
program files, and other components, as required to properly recover your database. Restore
2 uses BRCOM, the command-line user interface from which you enter and manage BACKUP
and RESTORE commands for SQL/MX objects and OSS objects. For more information about
the BRCOM command syntax, see the Backup and Restore 2 Manual.
To back up and restore SQL/MP tables or other SQL/MP objects, you must use the T9074
BACKUP and RESTORE utilities. For more information, see SQL/MP Installation and
Management Guide, SQL/MP Reference Manual, and the Guardian Disk and Tape Utilities
Reference Manual.
Utilities provide backup functionality for SQL executables and program modules stored in OSS
files. For more information, see the SQL/MX Reference Manual.
For more information, see “Planning Database Security and Recovery” (page 42) and the
“Performing Recovery Operations” (page 235).
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:
• Column definitions
• ANSI views
• Constraints
• Indexes
These features provide additional data integrity for SQL/MX databases:
• Database changes are monitored by TMF.
• Database access is restricted to SQL/MX statements.
• Integrity constraints on tables are enforced by the DBMS (database management system).
Referential integrity constraints, for example, depend on several layers of software for checking,
including the executor and disk processes.
• Database consistency is maintained by concurrency control.
TMF 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.
SQL/MX database access is restricted to SQL/MX statements, including Data Manipulation
Language (DML), Data Definition Language (DDL), Transaction Control, Resource Control and
Optimization, Stored Procedures, and Trigger statements. For more information about SQL/MX
statements, see the SQL/MX Reference Manual.
For each SQL/MX table, you can define up to five types of integrity constraints (Not Null, Unique,
Primary Key, Check, and Referential Integrity) that NonStop SQL/MX checks before allowing an
20 Introduction to SQL/MX Database Management