SQL/MX 3.2 Management Manual (H06.25+, J06.14+)

Table Of Contents
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 41) and the
“Performing Recovery Operations” (page 232).
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
INSERT, UPDATE, or DELETE operation to change a row in a table. If the change would violate
the constraint, NonStop SQL/MX prohibits it.
Concurrency control for database access provides different degrees of database consistency to
meet different needs. For any DML statement, you can specify access options by using the FOR
option ACCESS clause and, for a SELECT statement, by using this same clause, you can also
specify access options for individual tables referenced in the FROM clause. The possible settings
for options in a DML statement are: READ COMMITTED, READ UNCOMMITTED, SERIALIZABLE
or REPEATABLE read, SKIP CONFLICT, and STABLE. These access modes are maintained by shared
or exclusive locks on rows, sets of rows, partitions, and tables. For more information, see the
SQL/MX Reference Manual.
SQL/MX Database Features 19