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From Apache Wiki <wikidi...@apache.org>
Subject [Db-derby Wiki] Update of "SystemTables" by AndrewMcIntyre
Date Thu, 18 May 2006 06:44:43 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Db-derby Wiki" for change notification.

The following page has been changed by AndrewMcIntyre:
http://wiki.apache.org/db-derby/SystemTables

New page:
/!\ Under Construction /!\

This page contains a partial description of Derby's system tables,
captured from a mail thread in Jan 2006: http://www.nabble.com/System-tables-in-Derby-t1027940.html#a2666072.
Please revise and update as needed.



SYSTABLES has one row for each table in the database. Its primary key
is TABLEID, which contains system-generated values. The SCHEMAID is a
foreign key column, which references SYSSCHEMAS.

SYSSCHEMAS has one row for each schema in the database. Its primary
key is SCHEMAID.

SYSCOLUMNS has one row for each column of every table in the
database. Its primary key is (REFERENCEID, COLUMNNUMBER). REFERENCEID
is also a foreign key, which refers to TABLEID in SYSTABLES.

SYSCONSTRAINTS has one row for each constraint in the database
(primary, unique, foreign and check constraints). Its primary key is
CONSTRAINTID, which is a system-generated value. The TABLEID column
is a foreign key referring to SYSTABLES.TABLEID. The SCHEMAID column
is a foreign key referring to SYSSCHEMAS.SCHEMAID.

SYSCONGLOMERATES has one row for each heap (base table) and index in
the database. Its primary key is CONGLOMERATEID, which is a
system-generated value. The TABLEID column is a foreign key referring
to SYSTABLES.TABLEID. The SCHEMAID column is a foreign key referring
to SYSSCHEMAS.SCHEMAID. The ISCONSTRAINT column tells whether the row
represents the backing index for a primary key, foreign key or unique
constraint.

SYSKEYS has one row for each primary key or unique constraint in the
database. Its primary key is CONSTRAINTID, which is also a foreign
key to SYSCONSTRAINTS.CONSTRAINTID. The CONGLOMERATEID column is a
foreign key referring to SYSCONGLOMERATES.CONGLOMERATEID.

SYSFOREIGNKEYS has one row for each foreign key in the database. Its
primary key is (CONSTRAINTID, KEYCONSTRAINTID). The CONSTRAINTID
column is a foreign key refererring to SYSCONSTRAINTS.CONSTRAINTID,
and it contains the constraint id of the foreign key itself. The
KEYCONSTRAINTID is a foreign key referring to
SYSCONSTRAINTS.CONSTRAINTID, and it contains the constraint id of the
primary key that the foreign key refers to. The CONGLOMERATEID column
is a foreign key that refers to SYSCONGLOMERATES.CONGLOMERATEID, and
it contains the id of the backing index for the foreign key.

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