Abstract: A tool for the development of multiple-table database applications for client/server environments automates both capture of system requirements and code production. A client portion of a multiple-table, client/server database application for processing requests against a server database, is developed by first storing in a repository a description of the server database describing database entities within the server database and relationships between those database entities. Representations of the database entities are displayed, and an application drawing window is provided. The user drags and drops within the application drawing window one of said representations that represents a particular database entity. The tool then creates within the repository an entry for the particular database entity, and draws within the drawing window a representation of the particular database entity.

Abstract: In a data processing system having a relational database, novel relational operator means is provided that accepts a cursor defined against a database target. The system retrieves record occurrences from the target as defined by the cursor; the means accepts predefined display format signals and defines a stored screen image responsive to the format signals and the retrieved record occurrences. The screen image is displayed to a user on the system display, and is modified in response to enumerating signals input by the user through the system keyboard during such display. The operator means derives from the modified screen image and the cursor, output signals defining a result relation, membership in which is defined enumeratively and interactively through the keyboard. Alternatively, using other format signals for the display, characterizing signals are input by the user, and a result relation, membership in which is defined in terms of attributes in the target, is defined interactively.

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.

Abstract: In a relational database management system, errors can be corrected by an interactive user so that noninteractive operation can continue. A fetch module operates against a cursor to retrieve a record occurrence noninteractively for a selected operation. The selected operation is validated; an error condition can be set. When the selected operation is valid, the operation is performed, and a return signal is provided, causing the fetch module to retrieve the next record occurrence. When the selected operation is invalid, the fetch module responds to the error condition by operating interactively to display the previously retrieved record occurrence with an error message.

Abstract: In the maintenance of a stored relational database, signals representing record occurrences related to a record occurrence of a starting relation are retrieved. Stored relationship attribute signals, including specification of a common relationship field, are used to generate a generic cursor defined against the destination relation record occurence is selected, values of the specified relation; the generic cursor is stored, and when a starting field are copied from it to the generic cursor to form a completed cursor. Destination relation record occurrence signals defined by the completed cursor are accessed and stored. Retrieval can be carried out interactively, allowing an operator to select from a display the starting relation record occurrence and the operation of retrieving the related occurrences, and to view representations of the stored destination record occurrences.

Abstract: In a data processing system, application programs for the maintenance of a relational database may be constructed interactively and nonprocedurally. A data dictionary and screen-files are defined interactively and nonprocedurally. Data structures represent a meta-dictionary modeled as a relational database, a definition screen-file, a builder screen-file, and a set of archetype screen formats for modification.