Data processing: database and file management or data structures – Database design – Data structure types
Reexamination Certificate
1993-01-28
2001-07-31
Alam, Hosain T. (Department: 2172)
Data processing: database and file management or data structures
Database design
Data structure types
C707S793000
Reexamination Certificate
active
06269359
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a relational data base system, and more particularly, to an improvement in an execution procedure for querying a view table in a relational data base system. In the present invention, the execution procedure, which queries the content defined in the view table, is created in advance in a definition stage of the view table. As a result, it is possible to quickly realize the execution procedure to query the content defined in the view table so that it is possible for a user to easily utilize a relational data base system.
2. Description of the Related Art
Recently, relational data base systems have developed considerably in the field of computers. A relational data base is one kind of data base with a concept of providing easy utilization of a computer for a user. In the relational data base system, various technical terms, for example, “table”, “index”, “view table” and the like are frequently used in realizing the execution procedure. Further, the “SQL” is usually used as an operational language. SQL is a well known simplified language designed for data base access, and is different from a programming language.
In the relational data base system, various information is presented to the user in the form of a table. Two kinds of tables are used in this system. One is an actual table which is provided in the structure of the data base, and the other is a virtual table which is based on an actual table. A view table is comprised of a part of an actual table, or by a combination of a plurality of actual tables. The user queries the view table so that it is possible to easily and quickly obtain desired information stored in the data base.
When it is necessary to analyze a query sentence in the execution stage, analysis of the query sentence must be performed as quickly as possible.
In the above case, i.e., the analysis of the query sentence in the execution stage, it is necessary for the query to the data base to be in “text format”. This text format is frequently utilized in querying from a personal computer and in remote data base access between systems.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a relational data base system enabling reduction of a response time for a query to a data base in the case where the query is in a text format.
In one aspect of the present invention, there is provided a relational data base system having a function of view resolution for analyzing a query sentence in an execution procedure of a query from a user, using the content defined for a view table in the query designating the view table, converting the retrieval of the view table to that of an actual table, and creating the execution procedure. The system includes: an early bind definition unit for the view table for creating plural execution procedures in advance to query the defined view table in accordance with the structure of a query to the view table; a definition information dictionary operatively connected to the early bind definition unit; an execution procedure management unit provided in the definition information dictionary for storing plural execution procedures to realize the query to the view table previously created; an execution procedure composition unit operatively connected to the definition information dictionary for retrieving information of an execution procedure stored in the dictionary when receiving a query to the defined view table, extracting the execution procedure adapted to the query, and composing the extracted execution procedure with the query input from the user; and an execution unit operatively connected to the execution procedure composition unit for executing the composed execution procedure.
In a preferred embodiment, the definition information dictionary further includes: a table definition management table holding a particular kind of table, i.e., either the actual table or the view table, and an indication of the early bind for the view table; a content management table for the view table for holding the content of the definition; and an index management table for holding the name of an index.
In a preferred embodiment, the execution procedure management table includes column conditions for a corresponding view table, and a basic execution procedure for performing content described in the corresponding column conditions.
In an another aspect of the present invention, there is provided a method for creating plural execution procedures at an early bind in a relational data base system having a function of view resolution for analyzing a query sentence in an execution procedure for a query from a user, using a content defined in a view table for the query designating the view table, converting the retrieval of the view table to that of an actual table, and creating the execution procedure. The method includes steps of: creating an optimum execution procedure for the query to the view table; holding the created execution procedure in the definition information dictionary; estimating a first response time at an execution stage of the execution procedure; estimating a minimum response time necessary for creation of the execution procedure when performing the view resolution; creating the execution procedure to in advance realize the query when the first response time is larger than the minimum response time, in predicting reduction conditions in accordance with a storage structure of the actual table for obtaining the view table; and holding the created execution procedure with the reduction conditions in the definition information dictionary.
In still another aspect of the present invention, there is provided a method for composing an execution procedure in a relational data base system having a function of view resolution for analyzing a query sentence in an execution procedure for a query from a user, using a content defined in a view table for the query designating the view table, converting the retrieval of the view table to that of an actual table, and creating the execution procedure. The method includes the steps of: analyzing the syntax of a query input by a user; referring to the definition information dictionary for the view table that is the object of the query, and determining whether or not the execution procedure was previously created; selecting the execution procedure in accordance with the result of the YES/NO of conditions for the query when the execution procedure has been previously created; and composing the execution procedure to realize the query.
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Alam Hosain T.
Fujitsu Limited
Staas & Halsey , LLP
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