HP NonStop RDF, Руководство по управлению

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Consideration for Creating Backup Tables
Currently, you cannot use the CREATE LIKE statement to create backup or temporary tables
because CREATE LIKE does not preserve the original Guardian file names that are essential for
RDF.
At some point in the future when ANSI names are supported, CREATE LIKE will be a viable
means of creating backup or temporary tables, but until then the following discussion has the
utmost significance. NonStop SQL/MX will store data in rows on disk in a private format, which
does not necessarily correspond to the sequence in which the user specifies columns on CREATE
TABLE. For example, this CREATE TABLE statement:
create table t
(colx varchar(100),
coly int);
will cause rows to be laid out on disk in this format:
row-header coly-data colx-data
Consider these two statements, which will produce a logically equivalent table:
create table t
(colx varchar(100));
alter table t add column coly int;
The above two statements will produce this row layout on disk:
row-header coly-data colx-data
Applying audit generated for one row layout to a table that has a different row layout will not
work well.
Therefore, users must create backup tables in exactly the same way that the primary tables were
created. If you have never added any additional columns to your primary table after it was
created, use the CREATE LIKE statement. Of course, you must have registered your catalogs
first. See
“Creating NonStop SQL/MX Primary and Backup Databases” (page 323) for instructions.
If you have added columns to your primary table after it was created, you must take particular
care when creating the backup table, and you should not use the CREATE LIKE statement.
Rather, use the SHOWDDL command to see the order in which additional columns were added.
You must then create the table on the backup system in the same way in which the primary table
was created, and then add the additional columns to the backup table in the same order that
they were added to the primary table.
Restoring to a Specific Location
See the RESTORE information in the Guardian Disk and Tape Utilities Reference Manual for the
syntax of the RESTORE utility.
The LOCATION option allows you to change the physical location of NonStop SQL/MX objects
as they are restored. The LOCATION option is used to specify one or more mappings.
If you specify LOCATION, you cannot specify PARTONLY ON.
For synchronizing RDF backup databases, you need to use the fully qualified name option:
\A.$data01.ZSDUTRWA.HEBFRW00 TO \B.$data01.ZSDUTRWA.HEBFRW00
or
\A.$data01.ZSDUTRWA.HEBFRW00 TO \B.$dataAA.ZSDUTRWA.HEBFRW00
Example
Assume:
Consideration for Creating Backup Tables 333