SQL/MX 3.2.1 Management Manual (H06.26+, J06.15+)

secured for PUBLIC SELECT access so that you can query them. Table 1 (page 24) describes these
metadata tables and the schemas in which they are stored.
Table 1 SQL/MX Metadata Schemas
Schema ContentsSchema Name
One set of five system schema tables resides in the system
catalog under this schema. Use these system metadata
SYSTEM_SCHEMA
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).
The SYSTEM_DEFAULTS table resides in the system catalog
under this schema. This user metadata table contains the
SYSTEM_DEFAULTS_SCHEMA
default settings for options and other attributes used with
MXCI commands and SQL/MX statements.
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.
MXCS_SCHEMA
The stored procedure VALIDATEROUTINE and
VALIDATEROUTINE2 reside in the system catalog under
this schema. This schema contains no metadata tables.
SYSTEM_SQLJ_SCHEMA
One set of schema definition tables resides in each user
catalog under this schema. These system metadata tables
DEFINITION_SCHEMA _VERSION_vernum
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.
Three histogram tables (HISTOGRAMS,
HISTOGRAM_INTERVALS, and
user schemas
HISTOGRAM_FREQ_INTERVAL) 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.
The SYSTEM_SECURITY_SCHEMA tables reside in
NONSTOP_SQLMX_nodename. This metadata contains
SYSTEM_SECURITY_SCHEMA
system metadata that holds node-wide security related
information.
NOTE: VALIDATEROUTINE2 is the internal SPJ of system_SQLJ_schema that is supported on
systems running J06.05 and later J-series RVUs and H06.16 and later H-series RVUs. However,
VALIDATEROUTINE is used on systems running J06.04 and earlier J-series RVUS and H06.15 and
earlier H-series RVUs.
For more information, see “Querying SQL/MX Metadata” (page 105) and the SQL/MX Reference
Manual.
SQL/MX Database Object Types
Table 2 (page 24) describes SQL/MX object types. For more information about SQL/MP objects,
see the SQL/MP Installation and Management Guide and the SQL/MP Reference Manual.
Table 2 SQL/MX Object Types
DescriptionSQL/MX Object Type
A logical representation of data in which a set of records is represented as a
sequence of rows, and the set of fields common to all rows is represented by columns.
Table
A column is a set of values of the same data type with the same definition. The
intersection of a row and column represents the data value of a particular field in a
24 Introduction to SQL/MX Database Management