SQL/MX 2.x Reference Manual (G06.24+, H06.03+)

HP NonStop SQL/MX Reference Manual—523725-004
10-1
10 Metadata Tables
This section describes:
Changes to SQL/MP Metadata
SQL/MX Metadata Catalogs
SQL/MX Metadata Schemas and Tables
System Schema Tables
Definition Schema Tables
System Defaults Table
User Metadata Tables (UMD): Histogram Tables
MXCS Metadata Tables
NonStop SQL/MX stores system metadata for all objects in SQL/MX tables,
automatically creating and maintaining metadata as users create, alter, drop, or update
statistics for SQL/MX objects.
User tables are the tables you typically create as a user. You can modify data in and
alter or drop user tables, and you can grant privileges so that others can access and
change data in your user tables.
NonStop SQL/MX user metadata for histograms is stored in HISTOGRAMS and
HISTOGRAM_INTERVALS SQL/MX tables in each user schema. SQL/MP user
metadata for histograms is stored in the SQL/MP tables HISTOGRM and HISTINTS.
For more information about histograms, see User Metadata Tables (UMD): Histogram
Tables on page 10-68.
User metadata that specifies system default settings for options when you execute
SQL queries are stored in the SYSTEM_DEFAULTS table in schema
SYSTEM_DEFAULTS_SCHEMA. You can modify data in user metadata tables and
grant privileges on user metadata tables. You cannot alter or drop these tables.
System metadata about objects is stored in numerous tables in system schemas. You
cannot modify data directly in the system metadata tables, but they are secured for
PUBLIC SELECT access so that you can query them. The actual owner of the
metadata schemas is an authorization ID specified at the time NonStop SQL/MX is
installed.
All metadata tables are created with these extent attributes:
•
Extent sizes (128, 256)
•
MAXEXTENTS 512
The exception is the ALL_UIDS, table. Its extent sizes are (256, 1024) and maxextents
512.
In each of the table descriptions that follow:
•
Unless otherwise stated, timestamps are Julian timestamps.
•
Unless otherwise stated, character data is stored in uppercase letters except for
character columns that contain delimited identifiers, which are stored as is, but