SQL/MX 2.x Installation and Management Guide (G06.24+, H06.03+)

Introduction to SQL/MX Database Management
HP NonStop SQL/MX Installation and Management Guide—523723-004
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SQL/MX Metadata
For more information about these and other SQL/MX metadata tables, see Section 8,
Querying SQL/MX Metadata and the SQL/MX Reference Manual.
Table 1-1. SQL/MX Metadata Schemas
Schema Name Schema Contents
SYSTEM_SCHEMA One set of five system schema tables resides in the
system catalog under this schema. Use these system
metadata tables, which record the existence of
catalogs and schemas, to find the correct user catalog
on which to perform data lookup. When the catalog is
located, the definition schema is read to obtain details
about the object being queried (for example, a list of
Guardian locations for a table’s partitions).
SYSTEM_DEFAULTS_SCHEMA The SYSTEM_DEFAULTS table resides in the system
catalog under this schema. This user metadata table
contains the default settings for options and other
attributes used with MXCI commands and SQL/MX
statements.
MXCS_SCHEMA Five NonStop SQL/MX Connectivity Service (MXCS)
tables reside in the system catalog under this schema.
For more information, see the SQL/MX Reference
Manual.
SYSTEM_SQLJ_SCHEMA The stored procedure VALIDATEROUTINE resides in
the system catalog under this schema. This schema
contains no metadata tables.
DEFINITION_SCHEMA
_VERSION_vernum
One set of schema tables definition tables resides in
each user catalog under this schema. These system
metadata tables are created for a given catalog when
the first CREATE SCHEMA statement is executed for
the catalog. They store and maintain definitions of the
objects in the catalog.
user schemas Two histograms tables (HISTOGRAMS and
HISTOGRAM_INTERVALS) reside in each user
schema. These user metadata tables describe how
data is distributed with respect to a column or group of
columns within a table. The optimizer uses these
statistics to create efficient access plans.