Complied objective referential constraints in a relational database having dual chain relationship descriptors linked in data record tables
DCFirst Claim
1. A computer-implemented, relational data base management system comprising:
- (a) a first table containing data records;
(b) a second table containing data records;
(c) a third table containing data records;
(d) a first relationship descriptor, having pointer connections to the first table and the second table, for describing meta-data of a first referential constraint between the first and second tables, the meta-data including the first constraint'"'"'s parent and dependent tables and primary and foreign keys, the first relationship descriptor being a separate object internal to the data base management system;
(e) a second relationship descriptor, having pointer connections to one of the first two tables and the third table, for describing meta-data of a second referential constraint between one of the first two tables and the third table, the meta-data including the second constraint'"'"'s parent and dependent tables and primary and foreign keys, the second relationship descriptor being a separate object internal to the data base management system;
(f) a first chain for connecting the first and second relationship descriptors to their respective parent tables;
(g) a second chain for connecting the first and second relationship descriptors to their respective dependent tables;
(h) means for accessing the first and second relationship descriptors when any of the tables is to be modified; and
(i) means for enforcing the referential constraints described by the first and second relationship descriptors upon such modification.
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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.
107 Citations
12 Claims
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1. A computer-implemented, relational data base management system comprising:
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(a) a first table containing data records; (b) a second table containing data records; (c) a third table containing data records; (d) a first relationship descriptor, having pointer connections to the first table and the second table, for describing meta-data of a first referential constraint between the first and second tables, the meta-data including the first constraint'"'"'s parent and dependent tables and primary and foreign keys, the first relationship descriptor being a separate object internal to the data base management system; (e) a second relationship descriptor, having pointer connections to one of the first two tables and the third table, for describing meta-data of a second referential constraint between one of the first two tables and the third table, the meta-data including the second constraint'"'"'s parent and dependent tables and primary and foreign keys, the second relationship descriptor being a separate object internal to the data base management system; (f) a first chain for connecting the first and second relationship descriptors to their respective parent tables; (g) a second chain for connecting the first and second relationship descriptors to their respective dependent tables; (h) means for accessing the first and second relationship descriptors when any of the tables is to be modified; and (i) means for enforcing the referential constraints described by the first and second relationship descriptors upon such modification. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification