公开(公告)号：DE68916486D1

公开(公告)日：1994-08-04

申请号：DE68916486

申请日：1989-07-12

Applicant: IBM

Inventor： CRUS RICHARD ANTHONY ,  ENGLES ROBERT WILLIAM ,  HADERLE DONALD JAMES ,  HERRON HOWARD WINSTON

IPC: G06F12/00 ,  G06F9/44 ,  G06F17/30 ,  G06F15/40

公开(公告)号：DE68926422D1

公开(公告)日：1996-06-13

申请号：DE68926422

申请日：1989-07-12

Applicant: IBM

Inventor： CRUS RICHARD ANTHONY ,  DOCKTER MICHAEL JON ,  ENGLES ROBERT WILLIAM ,  HADERLE DONALD JAMES

IPC: G06F12/00 ,  G06F7/00 ,  G06F17/30

Abstract: An implementation of referential integrity in which descriptions of referential constraints are compiled into meta-data descriptions of the constraint rules and specifications. The meta-data descriptions of the constraints are stored in the form of objects called relationship descriptors. Each relationship descriptor contains a complete description of a referential constraint, either directly or by means of pointers to other objects such as record and index descriptors which contain information comprised in the constraint's specification. The relationship descriptors are linked into two types of chains by symbolic pointers. One type of relationship descriptor chain connects all relationship descriptors which have a common parent table. The other type of relationship descriptor chain connects relationship descriptors with common dependent tables. Both types of chains are anchored in respective fields in the tables' record descriptors. The use of meta-data descriptors facilitates both ready modification of the constraints, and speedy enforcement of the constraints by a single, shared procedure which may be embedded in the data base manager.

公开(公告)号：DE68926422T2

公开(公告)日：1996-11-07

申请号：DE68926422

申请日：1989-07-12

Applicant: IBM

Inventor： CRUS RICHARD ANTHONY ,  DOCKTER MICHAEL JON ,  ENGLES ROBERT WILLIAM ,  HADERLE DONALD JAMES

IPC: G06F12/00 ,  G06F7/00 ,  G06F17/30

Abstract: An implementation of referential integrity in which descriptions of referential constraints are compiled into meta-data descriptions of the constraint rules and specifications. The meta-data descriptions of the constraints are stored in the form of objects called relationship descriptors. Each relationship descriptor contains a complete description of a referential constraint, either directly or by means of pointers to other objects such as record and index descriptors which contain information comprised in the constraint's specification. The relationship descriptors are linked into two types of chains by symbolic pointers. One type of relationship descriptor chain connects all relationship descriptors which have a common parent table. The other type of relationship descriptor chain connects relationship descriptors with common dependent tables. Both types of chains are anchored in respective fields in the tables' record descriptors. The use of meta-data descriptors facilitates both ready modification of the constraints, and speedy enforcement of the constraints by a single, shared procedure which may be embedded in the data base manager.

公开(公告)号：DE68916486T2

公开(公告)日：1995-03-16

申请号：DE68916486

申请日：1989-07-12

Applicant: IBM

Inventor： CRUS RICHARD ANTHONY ,  ENGLES ROBERT WILLIAM ,  HADERLE DONALD JAMES ,  HERRON HOWARD WINSTON

IPC: G06F12/00 ,  G06F9/44 ,  G06F17/30

公开(公告)号：BR8904808A

公开(公告)日：1990-05-01

申请号：BR8904808

申请日：1989-09-22

Applicant: IBM

Inventor： CRUS RICHARD ANTHONY ,  DOCKTER MICHAEL JOHN ,  ENGLES ROBERT WILLIAM ,  HADERLE DONALD JAMES

IPC: G06F12/00 ,  G06F7/00 ,  G06F17/30 ,  G06F15/40

Abstract: An implementation of referential integrity in which descriptions of referential constraints are compiled into meta-data descriptions of the constraint rules and specifications. The meta-data descriptions of the constraints are stored in the form of objects called relationship descriptors. Each relationship descriptor contains a complete description of a referential constraint, either directly or by means of pointers to other objects such as record and index descriptors which contain information comprised in the constraint's specification. The relationship descriptors are linked into two types of chains by symbolic pointers. One type of relationship descriptor chain connects all relationship descriptors which have a common parent table. The other type of relationship descriptor chain connects relationship descriptors with common dependent tables. Both types of chains are anchored in respective fields in the tables' record descriptors. The use of meta-data descriptors facilitates both ready modification of the constraints, and speedy enforcement of the constraints by a single, shared procedure which may be embedded in the data base manager.

公开(公告)号：BR8901648A

公开(公告)日：1989-11-21

申请号：BR8901648

申请日：1989-04-07

Applicant: IBM

Inventor： CHANG PHILIP YEN-TANG ,  ENGLES ROBERT WILLIAM ,  OBERMANN DAVID FRANCIS ,  TRUMBLE MARY KATHLEEN

IPC: G06F17/30 ,  G06F20060101 ,  G06F15/40

Abstract: A relational database system having mixed data comprises means for selectively designating a column in a database table as being for single byte character set data only. Preferably, the user application can specify the subtype of character data within a column as the column is created or added by specifying FOR SBCS or FOR MIXED in either the CREATE TABLE statement or the ALTER TABLE statement. This can be done by specifying the subtype of the character data types including CHAR, VARCHAR, and LONG VARCHAR. Along with specifying the subtype as either for single byte data or for mixed data, means are preferably provided for specifying the codepage to be used for the column of the table in the database. The subtype of the character can then be recorded in terms of the code page attributes of the character data type as stored in the database system catalogs. This encoding scheme provides an efficient method of determining whether a column is only for single byte character set data or mixed data, and at the same time knowing the correct codepage that is to be used for that column simply by querying the code page columns within the database system catalogs.