EP0274392A2
Expired / Lapsed
EP
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Improved relational data base system
Assignee: Wang Laboratories Inc
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Filing: 1988-01-07
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Granted: —
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Expires: 2008-01-07
Abstract
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 (101) and the state of a set of rows in another base table (101). There are three kinds of dependent fields: a count field (107) which contains a count of the rows in the set, a sum field (105) which is the sum of a field in the rows of the set, and a base copy down field (113) 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 (103) which is used as a foreign key (111) in the set of rows of the other base table. The apparatus consists of components (313, 306) in the data dictionary which define the user-defined dependent field and the nature of the dependence, including any conditions thereon, and components (319) 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.
Inventors
- 👤 Val J. Huber
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 07:36
CPC Classifications
G; G06; G06F; G06F16/00; G06F16/20; G06F16/23; G06F16/2365; G06F16/28; G06F16/284
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
165 words
1) A relational data base system which includes data dictionary means (202), a first base table (101), and a second base table (101), 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 (227) responsive to data base operation commands and to the data dictionary for performing operations on the rows, in which a dependence may be maintained between a first user-defined field (105, 109, or 113) in a row in one of the base tables and the state of a row in the other of the base tables, and which is characterized by: dependence defining means (313) in the data dictionary for defining the dependence; and means (319) 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 state of the row.
Claim 2
Dependent Claim
165 words
1) A relational data base system which includes data dictionary means (202), a first base table (101), and a second base table (101), 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 (227) responsive to data base operation commands and to the data dictionary for performing operations on the rows, in which a dependence may be maintained between a first user-defined field (105, 109, or 113) in a row in one of the base tables and the state of a row in the other of the base tables, and which is characterized by: dependence defining means (313) in the data dictionary for defining the dependence; and means (319) 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 state of the row.
Claim 3
Dependent Claim
60 words
2) The relational data base system as set forth in claim 1 and further characterized in that: the dependence defining means further includes condition defining means (306, 327) for defining a condition to which the dependence is subject; and the dependence reestablishing means is further responsive to the condition defining means and reestablishes the dependence as determined by the condition.
Claim 4
Dependent Claim
126 words
3) The relational data base system as set forth in claim 2 and further characterized in that: the condition defining means includes executable condition code (306) for testing whether the condition exists and result indicating means (327) for indicating the result of an execution of the condition code and the dependence reestablishing means responds to the condition defining means by executing the condition code before altering the state of the row, determining a first result from the result indicating means, altering the state of the row, again executing the condition code, determining a second result from the result indicating means, comparing the first and second results, and reestablishing the dependence when the comparison indicates that the alteration of the state of the row affected the condition.
Claim 5
Dependent Claim
68 words
4) The relational data base system as set forth in claim 1 and further characterized in that: the one base table is referenced by the other base table; the dependence-defining means defines the user-defined field as containing an aggregate value representing a characteristic of certain rows in the other base table; and the dependence reestablishing means recomputes the aggregate value whenever a data base operation changes the characteristic.
Claim 6
Dependent Claim
61 words
5) The relational data base system as set forth in claim 4 and further characterized in that: the dependence defining means further includes condition defining means for (306, 327) defining a condition to which the dependence is subject; and the dependence reestablishing means is further responsive to the condition defining means and recomputes the aggregate value as determined by the condition.
Claim 7
Dependent Claim
40 words
6) The relational data base system as set forth in claim 5 and further characterized in that: the value of the condition is dependent on the value of a second user-defined field in the rows of the other data base.
Claim 8
Dependent Claim
34 words
7) The relational data base system as set forth in claim 5 and further characterized in that: the value of the condition is dependent on a value defined by the relational data base system.
Claim 9
Dependent Claim
47 words
8) The relational data base system as set forth in claim 4 and further characterized in that: the aggregate value is a count of the certain rows; and the dependence reestablishing means recomputes the count whenever a data base operation changes the number of the certain rows.
Claim 10
Dependent Claim
64 words
9) The relational data base system as set forth in claim 4 and further characterized in that: the aggregate value is a sum of the values of a second user-defined field in each of the certain rows; and the dependence reestablishing means recomputes the sum whenever a data base operation changes the value of the second user-defined field in any of the certain rows.
Claim 11
Dependent Claim
88 words
10) The relational data base system as set forth in claim 1 and further characterized in that: the one base table is referenced by the other base table; the dependence defining means defines a copydown field in each row of the other base table as containing a copy of the current value of the user-defined field; and the dependence reestablishing means copies the current value of the user-defined field into the copydown fields of the rows whenever a data base operation changes the value of the user-defined field.
References Cited (Backward Citations)
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