Relational database system
First Claim
1. In a relational data base system including data dictionary means, a first base table and a second base table, each of which has at least one user-defined row defined in the data dictionary in such fashion that the first base table and the second base table are referenced and referencing, and operational means responsive to data base operation commands and to the data dictionary for performing operations on the rows,means for maintaining a dependence between a first user-defined field in a row in one of the base tables and a row in the other of the base tables comprising:
- dependence defining means in the data dictionary for defining the dependence; and
means in the operational means responsive to the dependence defining means for reestablishing the dependence as defined in the dependence defining means whenever a data base operation alters the row.
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Accused Products
Abstract
Apparatus used in a relational data base system to maintain a dependence between a user-defined field in a row of one base table and the state of a set of rows in another base table. There are three kinds of dependent fields: a count field which contains a count of the rows in the set, a sum field which is the sum of a field in the rows of the set, and a base copy down field, which is a field in the rows of the set which contains a copy of a value in a field in the row of the one base table. The two base tables make up a referenced-referencing pair and the row from the one table has a primary key which is used as a foreign key in the set of rows of the other base table. The apparatus consists of components in the data dictionary which define the user-defined dependent field and the nature of the dependence, including any conditions thereon, and components in the data base system'"'"'s run time system for maintaining the dependence. Each time the state of a row in the referencing base table is altered, the run time system uses the data dictionary to determine whether there is a user-defined dependent field, and if there is, what kind of dependent field it is. Code in the run time system then reestablishes the dependence as required for the altered row.
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Citations
15 Claims
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1. In a relational data base system including data dictionary means, a first base table and a second base table, each of which has at least one user-defined row defined in the data dictionary in such fashion that the first base table and the second base table are referenced and referencing, and operational means responsive to data base operation commands and to the data dictionary for performing operations on the rows,
means for maintaining a dependence between a first user-defined field in a row in one of the base tables and a row in the other of the base tables comprising: -
dependence defining means in the data dictionary for defining the dependence; and means in the operational means responsive to the dependence defining means for reestablishing the dependence as defined in the dependence defining means whenever a data base operation alters the row. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification