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SYSTEM.CONSTRAINT

Description

A row of SYSTEM.CONSTRAINT represents a referential constraint defined with a CREATE CONSTRAINT statement.

View SYSCA.CONSTRAINT is defined on SYSTEM.CONSTRAINT.

Note: For more information, see SYSCA Objects.

Column name

Column description

Data type

Null specifi- cation

SCHEMA

Schema-name qualifier of the constraint.

CHAR(18)

NOT NULL

NAME

Constraint name.

CHAR(18)

NOT NULL

REFSCHEMA

Schema-name qualifier of the referenced table.

CHAR(18)

NOT NULL

REFTABLE

Name of the referenced table.

CHAR(18)

NOT NULL

TABSCHEMA

Schema-name qualifier of the referencing table.

CHAR(18)

NOT NULL

TABLE

Name of the referencing table.

CHAR(18)

NOT NULL

CTIME

Date and time the constraint was created.

TIMESTAMP

NOT NULL

NUMCOLUMNS

Number of columns in the constraint (foreign key).

SMALLINT

NOT NULL

REFCOLUMNS

Referenced table key column number array. Each eight bits contains the relative column number of a referenced column (for NUMCOLUMNS entries).

BINARY(64)

NOT NULL

COLUMNS

Referencing table foreign key column number array. Each eight bits contains the relative column number of a referencing column (for NUMCOLUMNS entries).

BINARY(64)

NOT NULL

NUMSORTCOLS

Number of columns in the sort key.

SMALLINT

NOT NULL

SORTCOLUMNS

Sort key column number array. Each eight bits contains the relative column number of a sort column (for NUMSORTCOLS entries).

BINARY(64)

NOT NULL

SORTORDER

Sort order indicator. Each byte indicates the order of a sort column (for NUMSORTCOLS entries):

  • A—Ascending
  • D—Descending

CHAR(32)

NOT NULL

CLUSTER

Referencing table cluster indicator:

  • Y—Clustered
  • N—Not clustered

CHAR(1)

NOT NULL

UNIQUE

Uniqueness indicator for sort key:

  • Y—Unique
  • N—Not unique

CHAR(1)

NOT NULL

TYPE

Type of constraint:

  • L—Linked
  • U—Unlinked
  • X—Linked indexed

CHAR(1)

NOT NULL

COMPRESS

Index keys compressed:

  • Y—Yes
  • N—No

CHAR(1)

NOT NULL

IXBLKLENGTH

Index block (SR8) length.

SMALLINT

NOT NULL

IXBLKCONTAINS

Number of keys in index block.

SMALLINT

NOT NULL

DISPLACEMENT

Index displacement (the number of pages by which bottom-level SR8 records are displaced from the referenced row).

SMALLINT

NOT NULL

REFNEXT

Offset to next db-key pointer within the referenced table.

SMALLINT

NOT NULL

REFPRIOR

Offset to prior db-key pointer within the referenced table.

SMALLINT

NOT NULL

NEXT

Offset to next db-key pointer within the referencing table.

SMALLINT

NOT NULL

PRIOR

Offset to prior db-key pointer within the referencing table.

SMALLINT

NOT NULL

OWNER

Offset to owner db-key pointer within the referencing table.

SMALLINT

NOT NULL

NUMSETS

Number of referenced rows when statistics were last updated.

INTEGER

NOT NULL

AVGMEMROWS

Average number of referencing rows per referenced row when statistics were last updated.

REAL

NOT NULL

LONGESTMEM

Highest number of referencing rows per referenced row when statistics were last updated.

INTEGER

NOT NULL

SECLONGMEM

Second highest number of referencing rows per referenced row when statistics were last updated.

INTEGER

NOT NULL

NUMLONGMEM

Number of referenced rows having LONGESTMEM referencing rows when statistics were last updated.

INTEGER

NOT NULL

AVGMEMPAGES

Average number of database pages containing referencing rows per referenced row when statistics were last updated. Rows accounted for in MAXMEMPAGES are not included in this average.

REAL

NOT NULL

MAXMEMPAGES

The number referenced rows whose referencing occupied more than 20 database pages when statistics were last updated. Rows accounted for in AVGMEMPAGES (above) are not included in this number.

INTEGER

NOT NULL

AVGAMEMCLUSCNT

Average number of I/Os required to read all referencing rows associated with a referenced row when statistics were last updated, if one buffer page was available. This count includes I/O to read the bottom-level SR8.

REAL

NOT NULL

AVGBMEMCLUSCNT

Average number of I/Os required to read all referencing rows associated with a referenced row when statistics were last updated, if three buffer pages were available. This count includes I/O to read the bottom-level SR8.

REAL

NOT NULL

AVGCMEMCLUSCNT

Average number of I/Os required to read all referencing rows associated with a referenced row when statistics were last updated, if five buffer pages were available. This count includes I/O to read the bottom-level SR8.

REAL

NOT NULL

AVGDMEMCLUSCNT

Average number of I/Os required to read all referencing rows associated with a referenced row when statistics were last updated, if 10 buffer pages were available. This count includes I/O to read the bottom-level SR8.

REAL

NOT NULL

AVGEMEMCLUSCNT

Average number of I/Os required to read all referencing rows associated with a referenced row when statistics were last updated, if 20 buffer pages were available. This count includes I/O to read the bottom-level SR8.

REAL

NOT NULL

AVGSR8ROWS

Average number of SR8s per referenced row in a linked indexed constraint when statistics were last updated.

REAL

NOT NULL

LONGESTSR8

Highest number of bottom-level SR8s per referenced row in a linked indexed constraint when statistics were last updated.

INTEGER

NOT NULL

SECLONGSR8

Second highest number of bottom-level SR8s per referenced row in a linked indexed constraint when statistics were last updated.

INTEGER

NOT NULL

NUMLONGSR8

Number of referenced rows in a linked indexed constraint having LONGESTSR8 SR8s when statistics were last updated.

INTEGER

NOT NULL

AVGSR8PAGES

Average number of pages containing bottom-level SR8s per referenced row in a linked indexed constraint when statistics were last updated. This average does not include pages accounted for in MAXSR8PAGES.

REAL

NOT NULL

MAXSR8PAGES

The number of referenced rows in a linked indexed constraint when statistics were last updated for which the number of pages containing bottom-level SR8s is greater than 20.

INTEGER

NOT NULL

AVGSR8LEAFS

Average number of bottom-level SR8s per referenced row in a linked indexed constraint when statistics were last updated.

REAL

NOT NULL

AVGSR8LEVELS

The average high level number per referenced row in a linked indexed constraint when statistics were last updated. Level number refers to the number of levels above the bottom level.

REAL

NOT NULL

AVGASR8CLUSCNT

Average number of I/Os required to read all SR8s associated with a referenced row in a linked indexed constraint when statistics were last updated, if one buffer page was available.

REAL

NOT NULL

AVGBSR8CLUSCNT

Average number of I/Os required to read all SR8s associated with a referenced row in a linked indexed constraint when statistics were last updated, if three buffer pages were available.

REAL

NOT NULL

AVGCSR8CLUSCNT

Average number of I/Os required to read all SR8s associated with a referenced row in a linked indexed constraint when statistics were last updated, if five buffer pages were available.

REAL

NOT NULL

AVGDSR8CLUSCNT

Average number of I/Os required to read all SR8s associated with a referenced row in a linked indexed constraint when statistics were last updated, if 10 buffer pages were available.

REAL

NOT NULL

AVGESR8CLUSCNT

Average number of I/Os required to read all SR8s associated with a referenced row in a linked indexed constraint when statistics were last updated, if 20 buffer pages were available.

REAL

NOT NULL

FILLER

Reserved for future use.

BINARY(40)

NOT NULL