JPH08305615A - Data base inquiry system - Google Patents

Abstract

PURPOSE: To attain the easy use of a data base even with an application program that does not presume the use of the data base. CONSTITUTION: A data input part 1 inputs an inquiry statement of SQL and a format designation statement which designates the data format of an application program. An inquiry processing part 3 performs the syntactic analysis of the inquiry statement and sends the SQL inquiry statement to a data base part 5 as long as the statement is correct. The part 5 performs a retrieval operation in response to the inquiry statement. A post-processing management part 4 converts the result retrieved by the part 5 into the format of the application program based on the format designation statement inputted by the part 1. Then the part 4 sends the converted format to the application program.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a database inquiry system adapted to change the display method of search results in accordance with the user's display request.

[0002]

2. Description of the Related Art In relational database systems, an inquiry language called SQL has been prepared. Also, in the object-oriented database system, it is general to provide an inquiry language called object SQL which is an extension of SQL.

SQL is a language that can express a data definition operation and a data operation operation, and the data operation operation includes a search operation and an update operation. Here, the search calculation will be described.
The search operation is expressed by the following formula. select a1, ..., ak from R1, ..., Rm where p where Ri is a relation and is a relation to be searched (j
= 1, ..., m). ai is an attribute of these relationships, which is derived as a result, and is called a target attribute (i
= 1, ..., k). Also, a1, ..., Ak are called target lists. p is a conditional expression. The conditional expression is the following basic expression: aθb or aθv, a logical product (AND) of conditional expressions, a logical sum (OR) of conditional expressions, or a negation (NO) of conditional expressions.
T). Here, a and b are attributes in the relation to be searched, and v is a constant. θ is a comparison operator (<, ≦, =, ≧,>, ≠). Also, the above aθ
b is called a coupling basic expression, and aθv is called a limiting expression.

[0004]

However, the following are problems with the conventional database inquiry by SQL. Conventionally, when an application program uses a database, a method of embedding SQL in the programming language of the application program has been used. That is, it was necessary to develop the application program itself on the premise of using the database. Therefore, existing application programs that are not supposed to use the database in advance cannot use the data in the database.

From this point of view, it has been desired to realize a database inquiry system capable of easily using a database even for an application program which is not supposed to use the database.

[0006]

In order to solve the above problems, the database inquiry system of the present invention adopts a mechanism that takes post-processing into consideration in the inquiry statement of the database. It is realized by the following configuration. That is, the database inquiry system of the present invention includes a data input section for inputting an SQL inquiry statement and a format specification statement for specifying a data format of an application program that uses search data of a search target database, and this data input section. The database is searched based on the SQL query text input to, and the database part that outputs the search result, and the search result is converted to the application program format based on the format specification statement and output to the application program. And a post-processing management unit for performing the same.

[0007]

In the database inquiry system of the present invention, when an SQL inquiry statement and a format specification statement for specifying the data format of the application program are input to the data input section, the database section will output the S statement.
The database is searched based on the inquiry text of QL. When the search result is obtained, the post-processing management unit outputs the search result to the application program as a data format corresponding to the format designation statement input to the data input unit.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a configuration diagram of a database inquiry system according to an embodiment of the present invention. The system shown in the figure comprises a data input unit 1, a user interface management unit 2, an inquiry processing unit 3, a post-processing management unit 4, a database unit 5, and an application program 6.

The data input unit 1 is composed of an input device such as a keyboard and a mouse in a computer system. A user inputs a command for searching a database by using these input devices, and this is input to the user interface management unit 2. It is a supply device. The user interface management unit 2 has a function of receiving a command from the data input unit 1 and supplying data for displaying a search result and browsing contents to the application program 6. The inquiry processing unit 3 checks whether the inquiry sentence input by the user is syntactically correct. If it is not correct, the user interface management unit 2 causes the user to display an error message on a display (not shown), and if correct, the database unit 5 is supplied with the user's inquiry text.

The post-processing management unit 4 converts the search data into an output format according to the format specification statement written in the query language and outputs it to the application program 6. The database unit 5 is composed of a relational database system. The application program 6 is an application program such as a spreadsheet program, and displays retrieved data (text, image, graphics, etc.) and browsing data.

Next, the operation of the database inquiry system having the above configuration will be described. FIG. 2 is an operation flowchart of the database inquiry system of the present invention. <Step S1> When the user activates the database unit 5 (database system) by the activation command,
Enter database search mode. <Step S2> When the user inputs an inquiry sentence and the inquiry processing unit 3 is started by the start command, the execution of the inquiry processing unit 3 starts. The inquiry sentence is expressed by the following formula.

For F select a1, ..., ak from R1, ..., Rm where P

Here, the select clause, from clause, and where clause are
It is based on the general SQL syntax. To briefly explain this, R1 and Rm are derived relations. Further, a1, ..., Ak are attributes of these relationships and are derived as a result. Furthermore, P is a conditional expression. The for clause is a format specification statement and is a clause introduced for inquiring a database in consideration of post-processing. It describes a program to specify the format of the application.

<Step S3> The inquiry processing unit 3 performs a syntax analysis on the inquiry sentence input in step S2 to check whether the inquiry sentence matches the inquiry language syntax. <Step S4> The inquiry processing unit 3 inspects whether the inquiry sentence input in step S2 satisfies the schema of the database. Here, the schema of the database system is a time-invariant logical one in the data structure of the database.

<Step S5> With respect to the inquiry text on the system side generated in step S2, an execution plan is generated based on the rewriting rule. <Step S6> The execution plan is executed according to the execution plan generated in step S5. At the time of execution, a search is performed by calling the execution function of the database unit 5. <Step S7> The inquiry processing unit 3 performs step S6.
The data retrieved in step 3 is passed to the post-processing management section 4 via the user interface management section 2. The post-processing management unit 4 converts the passed data into the format of the for clause.

<Step S8> The application program 6 displays the data of the format converted by the post-processing management section 4 to the user. <Step S9> It is determined whether the user inputs the inquiry sentence again. When input again, the processing from step S3 is performed. On the other hand, when the end button is pressed, the database search mode is ended.

<Step S10> If the query text of the user is a syntactical error or a semantic (semantic) error compared with the schema of the database, the query processing unit 3 determines the user interface management unit. Notify 2 of the error. The user interface management unit 2 notifies the user of a syntax error or a semantic error.

Next, the above-mentioned operation will be described with reference to a concrete example. FIG. 3 is an explanatory diagram of the schema structure of the database. Here, it is assumed that all data in the database section is in English. obase, geosBib, and bibs are collections of document data. In the obase schema structure, author, title, publication, abst
It contains the attributes ract, year, and text. Also, geosBi
In the schema structure of b, author, organizatio
Includes n, title, publication, comment, year, and text attributes. In addition, in the schema structure called bibs, author, organization, title, publication,
Includes attributes such as keyword, year, and text. In addition, text
Is an attribute indicating the body of the paper.

<Execution Operation 1> The user inputs an inquiry sentence. FIG. 4 is an explanatory diagram of the inquiry input screen. In this example, a search for a document issued in 1989 is shown. Further, the for clause specifies that it is "HTML". This indicates that the process of passing the data retrieved from the database section to the interface in the HTML format is activated. In addition, HTML
Is a format that the application program 6 can accept.

Specifically, when written in SQL syntax, it indicates that the following inquiry was made. for “HTML” select * from id in bibs where id.year = “1989”

<Execution Operation 2> In FIG. 4, when the user presses the "Query Start" button, the above step S
3. Perform step S4 to check whether the error is syntactic or semantic. <Execution operation 3> Steps S5 and S6 are performed, and f
Display the data according to the specification of the or clause. FIG. 5 is an output result at this time and is an explanatory diagram of the search screen.

Next, a method will be described in which the user modifies only the description of the for clause of the above-described execution operation 1 to display data. <Execution Operation 4> Instead of “HTML” in the for clause of execution operation 1, “tex” is used. In addition, this "tex" means HT
Like ML, it is a format type. <Execution operation 5> When the user presses the "Query Start" button, steps S3 and S4 are performed, and
Or check if there is a semantic error. <Execution operation 6> Steps S5 and S6 are performed, and f
Display the data according to the specification of the or clause. At this time, the data is shaped into "tex", the tex program is executed, the tex previewer is executed, and the following is displayed. FIG. 6 shows the output result at this time.

As described above, according to the above-described embodiment, the post-processing is embedded in the query language, and the query language for
The query result can be switched by switching the output destination with a phrase. Also, as post-processing, by converting the result of the inquiry into a form that can be input to the existing application program and specifying the program that exchanges data with the existing program, the existing application program that does not have access to the database can be used. Can be used.

In the above embodiment, an example in which the database unit 5 is a relational database system has been described, but the same effect can be obtained even if the database is an object-oriented database.

In the above embodiment, the "HTM" is added to the for clause.
Although an example in which the output is output to HTML by specifying "L" is shown, by creating a program conversion program for converting into the format used in the application program in the for clause and specifying the program in the for clause,
It can be adapted to various data formats.

Further, in the above embodiment, the application program 6
Although the post-processing management unit 4 is independently provided to perform the format conversion to the above, the inquiry processing unit 3 may be configured to include the function of the post-processing management unit 4. In other words, the user may specify the format to be converted, and the inquiry processing unit 3 may convert the search result into the specified format when executing the search.

[0027]

As described above, according to the database inquiry system of the present invention, the format of the application program that uses the search result is input together with the inquiry statement of the database, and the post-processing management unit enters this format specification statement. Based on this, since the search result is converted into the format of the application program and output, the database can be easily used even if the application program does not assume the use of the database.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a database inquiry system of the present invention.

FIG. 2 is an operation flowchart of the database inquiry system of the present invention.

FIG. 3 is an explanatory diagram of a schema structure of a database in the database inquiry system of the present invention.

FIG. 4 is an explanatory diagram of an inquiry input screen in the database inquiry system of the present invention.

FIG. 5 is an explanatory diagram of a search screen in the database inquiry system of the present invention.

FIG. 6 is an explanatory diagram of a search output result screen in another format in the database inquiry system of the present invention.

[Explanation of symbols]

 1 data input unit 3 inquiry processing unit 4 post-processing management unit 5 database unit 6 application program

Claims (1)

[Claims] 1. A data input unit for inputting an SQL query sentence and a format designation sentence for designating a data format of an application program that uses search data of a search target database, and a data input unit input to the data input unit. A database part that outputs a search result based on the SQL query statement, and the search result is converted into the format of the application program based on the format specification statement. A database inquiry system comprising a post-processing management unit for outputting.