SQL/MP Reference Manual

HP NonStop SQL/MP Reference Manual—523352-013
C-8
Catalogs
Catalogs
An SQL/MP catalog is a set of tables and indexes that describe SQL objects. Tables in
the set are called catalog tables and SQL creates them—along with their indexes—
when you execute a CREATE CATALOG statement.
Each SQL/MP catalog (the set of catalog tables and their indexes) resides on its own
Guardian subvolume, and the name of that subvolume is also the name of the catalog.
The name has the same form as the subvolume portion of a Guardian file name:
[\node.][$volume.]subvol
For example, \SYS1.$VOL1.SALES might be the fully qualified name of a catalog with
the simple name SALES. If you omit \node or $volume, SQL uses the current default
node and volume to expand the catalog name. (For more information about Guardian
names, see Guardian Names on page G-7.)
Each node on which NonStop SQL/MP is used has one special catalog called the
system catalog (described under System Catalog on page S-92) and might have many
other catalogs. Each table, view, index, partition, collation, or catalog table located on a
node must be described in a catalog on the same node. Normally, an SQL program is
registered in a catalog, too (enabling SQL to locate affected programs when you
change definitions of tables, views, indexes, or collations), but you can create
unregistered programs if necessary.
A volume can have many catalogs. A subvolume can have only one catalog. Each
catalog can describe objects from any subvolume and volume on the same node.
You can create your own tables, indexes, views, and files on a subvolume that includes
an SQL catalog, but it is better to create such objects in other subvolumes, if a later
release of NonStop SQL/MP could add new tables or indexes to the catalog. (The
UPGRADE CATALOG command would be unable to upgrade your catalog if a new
catalog table had the same name as a table or file you created on the catalog
subvolume.)
Each catalog has a version and a format version associated with it. The catalog
version indicates the newest version of objects that can be registered in the catalog.
The catalog format version indicates the oldest version of the SQL/MP software that
can access the catalog. (For more information, see Versions
on page V-6.)
Table C-1
briefly describes catalog tables and indexes. For more information about a
specific catalog table, see the separate entry for that table.
Table C-1. Catalog Tables and Indexes (page 1 of 2)
Table Function
BASETABS Describes the attributes of tables
CATALOGS Describes the catalogs on a node (present only in system catalogs)
COLUMNS Describes the columns of tables