JPH01232428A - Data base enquiry processor - Google Patents

Abstract

PURPOSE:To develop a data base enquiry program smoothly by generating an object program which performs retrieval by referring to data base definition information at the time of execution. CONSTITUTION:When the data base definition information 34 is referred to, an enquiry language compiler 60 generates an executable object program 51 by referring to the definition information, but when not, an inexecutable object program 51 is generated without referring to the definition information. An object converting means 50 converts the inexecutable object program 51 into an executable object program 55 by referring to the data base definition information 34 provided to a data base control system 30 at the time of retrieval execution. Consequently, a program which contains data base enquiry commands including the data base definition information that is not present at the time of application program development is developed smoothly.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a database inquiry processing device that uses various databases to perform searches and the like to obtain predetermined data.

(Prior Art) When an information processing device executes a certain program, the program may use part of data stored in a specific database. Alternatively, the operator may select specific data in a database.
There are cases where a command is input from a terminal device to directly search and read.

In this case, the database management system performs a syntax check to check whether there are any grammatical errors in the search command, that is, a database inquiry command, and compiles to generate an object program to efficiently search the database according to the command. It is done.

This procedure will be explained using a database query processing device using a relational database as an example.

FIG. 2 first shows an example of the contents of the relational database.

A relational database is a database in which a large amount of tabular data can be searched three-dimensionally using various keys.For example, as shown in Figure 2, for tabular data such as an employee allocation table, In the name column, employee names are arranged in alphabetical order, for example, in the employee number column, the code assigned to each employee is shown as a 6-digit number, and in the affiliation column, the names are arranged in alphabetical order. and an affiliation code consisting of a combination of three digit numbers are arranged.

In addition, this table data is arranged in alphabetical order based on the name column, so for convenience when searching using a column other than the name as a key, the employee number order index 1 or department Code order index 2 etc. are prepared.

When searching a relational database of this type, for example, the following instructions are included in the application program. Of course, you can also manually do this directly from the keyboard.

5ELECT Name FROM Table name WHERE
Name=゛Oki Abe°.

With the above database inquiry command, the second
Data such as the employee number of the employee "Okitabe" shown in the figure is incorporated into the application program.

FIG. 3 shows a block diagram of a database inquiry processing device that executes processing when such a database inquiry command is input from a terminal device.

This device, when a database inquiry command 12 is input from the terminal device 10 via the communication line 20,
The database management system 30 receives this information and searches the database 40.

It is assumed that an application program 11 is created in this terminal device 10 and includes a database inquiry command 12 therein.

The database management system 30 includes, for example, the communication line 20
It consists of a host computer to which a large number of terminal devices 10 (not shown) are connected via a host computer.

This database management system 30 includes a query language compiler 3 that receives database query commands 12 and generates object programs 32.
1 (also called an interpreter) is provided. Further, a database access means 33 is provided here to access the database 40, and database definition information 34 is prepared therein.

This is information created based on the contents of the database 40, and is information used by the query language compiler 31 when generating the object program 32.

For example, as shown in the figure, the database definition information 34 includes information on the name of a data set, such as table name and column name, information on the structure of data, such as data type and data length, and information on efficiency of access to the data set. Information includes, for example, the presence or absence of an index, selection rate, access right information for a data set, etc.

Here, the table name is the name of table data such as the employee allocation table shown in FIG. In addition, the column name refers to the name of the column, such as the name or employee number. What is a data type?
For example, in the case of a name, it is displayed in kanji or katakana, and in the case of an employee number, it is information representing the method of representing the data, such as a decimal number. The data length is information regarding the number of characters in each column, etc. For example, in the employee allocation table shown in FIG. 2, the presence or absence of an index is information indicating whether an index 1 in order of employee number and an index 2 in order of affiliation code are prepared. The selection rate indicates the ratio of the search result data to the data of the population according to the inquiry command, and the access right refers to the ratio of the data in the search results to the population data according to the inquiry command. This is information regarding whether or not the

The query language compiler 31 performs a syntax check on the database query command 12 and further compiles the database query command 12 while referring to the database definition information 34 to generate an object program 32. The database access means 33 uses this object program 32 to search the database 40, converts the data type as necessary, and sends the search results to the application program 1.
Respond to 1. The application program 11 thereby takes in necessary data and executes predetermined processing.

Incidentally, conventional techniques for efficiently compiling database inquiry commands in such a relational database management system have been disclosed, for example, in Japanese Patent Laid-Open No.
It is introduced in Publication No. 274433 and the like.

(Problem to be Solved by the Invention) Incidentally, the development of application programs for accessing such databases is mainly performed on the computer side where database definition information exists. However, as databases become larger and development environments become more distributed, when developing this application program, the database to be accessed and its database definition information may be under development and may not yet exist, or even if they do not exist. However, there are an increasing number of cases in which it is not possible to refer to the content because the content is insufficient.

When compiling an application program that includes a database inquiry command, an object program cannot be generated based on the inquiry command unless database definition information exists on the computer.

Therefore, in such an environment, there is a problem that application programs cannot be completely compiled.

The present invention has been made in view of the above points, and provides a database inquiry processing device that can provide a program environment that enables advanced development of application programs regardless of whether database definition information exists or not. The purpose is to

(Means for Solving the Problems) A database inquiry processing device of the present invention is one in which a database inquiry command is inputted from an input device, and the database management system searches a database according to the database inquiry command and responds to the database inquiry command. The database management system includes a query language compiler that generates the object program for executing the search based on the database inquiry command manually input from the input device, and a database access system that executes the search of the database using the object program. and object conversion means for checking the object program before executing a search, the query language compiler comprising:
If database definition information that reveals the configuration of the database can be referenced, an executable object program is generated with reference to the database definition information, and if the database definition information cannot be referenced, an executable object program is generated that does not refer to the database definition information. The object converting means generates an object program, and converts an unexecutable object program among the object programs generated by the query language compiler into a non-executable object program.
The present invention is characterized in that when a search is executed, the database definition information provided in the database management system is referred to and converted into an executable object program.

(Operation) If the database definition information exists, the above device generates an executable object program that refers to this database definition information, and in other cases, performs a syntax check on parts that are not related to the database definition information. Then, an unexecutable object program is generated that omits reference to database definition information. This allows the application program to be compiled without any problems.

On the other hand, when actually performing a search, the object converting means converts an unexecutable object program into an executable object program by referring to database definition information already provided in the system. Thereby, it is possible to smoothly develop a program that includes a database inquiry command including database definition information, which does not exist when developing an application program.

(Example) Hereinafter, the present invention will be explained in detail using embodiments shown in the drawings.

FIG. 1 is a block diagram showing an embodiment of a database query processing device of the present invention.

This device has a configuration in which an input device 10 operated by an operator and a database management system 30 are connected. These are built into, for example, a single host computer.

In the input device 10, an application program 11 is created, in which a database inquiry command 12 is included, and this is input into the database management system 30.

The database management system 3o has a database access means 33 for searching the database 40,
Here, database definition information 34 as previously explained using FIG. 3 is provided. In addition to this, a query language compiler 60 that receives the database query command 12 and an object conversion means 50 that operates when the query command is executed are provided.

The query language compiler 6o includes a query interpreting means 61, a database definition information determining means 62, a query optimizing means 63, a query simplifying means 64, and an object generating means 65. The object converting means 50 also includes an unexecutable object program 5.
1 or an executable object program 52 and determines the object type thereof; and an object converting section 54 that converts the unexecutable object program 51 into an executable object program 55. .

In the above device, when a database inquiry command 12 is input from the input device 10, the query language compiler 60 generates an executable object program 52 if there is database definition information 34, and if there is no database definition information 34, the query language compiler 60 generates an executable object program 52. An unexecutable object program 51 is generated.

This completes the compilation of the application program 11, but actually the database 40
When attempting to search for
Perform a search.

4 and 5 illustrate the configurations of the non-executable object program 51 and the executable object program 52.

The object types 510 and 520 are composed of flags for identifying non-executable object programs and executable object programs, and these flags allow the object converting means 50 shown in FIG.
Determine whether to convert the object program. That is, for the non-executable object program 51 shown in FIG. 4, since there is no database definition information, these pieces of information are used for instructions to refer to the definition information at the time of execution. Further, regarding the executable object program 52 shown in FIG. 5, database definition information already exists and there is no need to refer to the definition information at the time of execution, and it is used as an instruction to suppress this.

Next, the table identification information 511.521 is a part that processes the table name of table data as explained in FIG. The table ID defined by the database definition information 34 is input. This table ID is a code for identifying the table of each database.

Column identification information 512 or 522 is information representing a column such as name shown in FIG. A column ID similar to the command and data type information of data forming the column are written.

Further, in the inquiry condition 513 or 523, search conditions such as keys, AND, or, etc. for searching the table are input. This is simplified for convenience in program execution, and when database definition information is referenced, it is optimized to the best search method for that database. Note that a specific method of such optimization is described, for example, in Japanese Patent Application Laid-Open No. 62-274433 introduced above. This optimization allows the program execution time to be minimized even when performing the same search.

Further, in the data type conversion information 514 or 524, information for executing the conversion when the data type of data read from the database and the data type requested by the application program 11 are different is input. The non-executable object program 51 is incomplete because the data type on the database side is unknown, but the executable object program 52 is manually entered with data type conversion information completed.

Finally, the access route information 515 or 525 is information such as tables and indexes that are referred to during search operations. 52 is input in its completed form.

The query language compiler 60 in FIG. 1 performs the operation of generating the object program shown in FIGS. 4 and 5 in this way, and the operation will be explained in more detail using a flowchart.

FIG. 6 is an operational flowchart of the query language compiler 60.

First, when an inquiry command is input, a syntax check is executed in the inquiry interpretation means 61 (FIG. 1) (step Sl). This is a so-called grammar check, and is a process to check if there are typographical or grammatical errors in the input command.

Next, the database definition information 34 (FIG. 1) is referred to (step S2). Database definition information determining means 62
(FIG. 1) shows that for the database access means 33,
An inquiry is made as to whether the database definition information 34 of the target database is prepared, and if the definition information is present, the process proceeds to step S4; if not, the process proceeds to step S7 (step S3). .

If there is database definition information 34, the definition information is imported (step S4).

Then, the query optimization means 63 (FIG. 1) is called. This query optimization means 63 is a program for generating the executable object program 52 shown in FIG. Through this process, the executable object program 52 is generated (step S6
), compilation ends.

On the other hand, if there is no definition information, the inquiry simplifying means 64 (FIG. 1) is called (step S7). This is a program that generates an unexecutable object program 51 as shown in FIG.

Then, when the non-executable object program is generated (step S8), this compilation is completed.

Due to the above operation of the query language compiler 6o,
Compilation of the application program regarding the database inquiry command is completed regardless of the presence or absence of database definition information.

FIG. 7 is a flowchart illustrating a more specific operation of the query optimization means shown in FIG.

First, table information in the database definition information 34 shown in FIG. 1 is fetched from the contents of the inquiry command (step Sl). Then, it is determined whether or not the column requested for search exists in this table information (step S2). If a column exists, the column information is imported by referring to the database definition information 34 (step S3).

This process is not performed if the column does not exist in the table.

Then, it is determined whether the data type of the inquiry and the data type in the database definition information are the same (step S4). Here, if the data types are the same, there is no need for conversion and the process moves to step S7. If the data types are not the same, it is determined whether the data types can be converted (step S5). If data type conversion is not possible, the process moves to step S7, and if possible, data type conversion is executed (step S6).

Next, it is determined whether the inquiry conditions can be simplified (step S7). If simplification is possible, perform the simplification by rearranging the conditions, etc. (step S8)
. If simplification is not possible, the process directly proceeds to the next step S9. In step S9, an access route is determined.

Finally, the inquiry object type is set (step 510).

As described above, executable object program 5
2 is generated.

On the other hand, the query simplification means 64 that generates an unexecutable object program determines whether the query conditions can be simplified in step S7 in FIG. (step S8), and determines the object type (step S51).
Only the three steps 0) are performed. .

Next, when the program compiled in this way actually attempts to search the database 40, the object conversion means 50 shown in FIG. It will be judged. This determination is made by the object type determining means 53 identifying the object type 510 or 520 shown in FIG. 4 or 5. Here, if it is determined that the object program is not executable, the object conversion unit 54 converts the program to obtain an executable object program.

This object converting unit 54 converts the non-executable object 51 into an executable object 55 by executing the process completely similar to that shown in FIG. Thereafter, the database access means 33 uses the executable object program to actually search the database 40 and responds the search results to the application program 11.

The present invention is not limited to the above embodiments.

In the above embodiments, a relational database is used as an example of the database, but the present invention can be similarly applied to, for example, a hierarchical database, a network type database, and the like. Furthermore, the structure of the object program can be modified in various ways depending on the type of database. Furthermore, the structure and operation of the query language compiler, object conversion means, etc. may be modified as appropriate as long as the above functions are provided.

(Effects of the Invention) According to the database inquiry processing device of the present invention described above, when database definition information already exists, it is possible to generate an object program for executing an optimal database search. On the other hand, even if the database definition information does not exist, a necessary syntax check is performed on the database inquiry command, and upon execution, an object program that can immediately refer to the database definition information and perform a search is generated. This allows the development of database inquiry programs to proceed smoothly in various development environments.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a database query processing device of the present invention, FIG. 2 is an explanatory diagram of a relational database suitable for implementing the present invention, FIG. 3 is a block diagram of a conventional database query processing device, and FIG. 4 is an execution diagram. FIG. 5 is an explanatory diagram of an executable object program, FIG. 6 is a flowchart of the operation of the query language compiler, and FIG. 7 is a flowchart of the operation of the query optimization means. DESCRIPTION OF SYMBOLS 10... Input device, 11... Application program, 12... Database inquiry command, 30... Database management system, 33... Database access means, 34... Database definition information, 40... Database, 50... Object conversion means, 51... Unexecutable object program, 52...
- Executable object program, 53... Object type determination means, 54... Object converter, 55... Executable object program, 6o...
- Inquiry language compiler, 61... Inquiry interpretation means, 62... Database definition information determination means, 63...
Query optimization means, 64... Query simplification means, 65... Object generation means. Patent applicant: Oki Electric Industry Co., Ltd.

Claims (1)

[Scope of Claims] A database inquiry command is input from an input device, and the database management system searches the database according to the database inquiry command and responds to the database inquiry command, wherein the database management system comprises: a query language compiler that generates the object program for executing the search based on the database inquiry command; a database access means that executes the search of the database using the object program; and an object conversion means for checking, the query language compiler: if database definition information clarifying the configuration of the database can be referenced, generates an executable object program with reference to the database definition information; If the object cannot be referenced, an unexecutable object program is generated with reference to the database definition information omitted, and the object converting means converts the unexecutable object program among the object programs generated by the query language compiler into a non-executable object program during search execution. A database inquiry processing device, characterized in that it operates to convert into an executable object program by referring to the database definition information provided in a database management system.