JP2942414B2 - Virtual database method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a database having a data operation function such as data search, registration, update, and deletion in an information processing system, and more particularly to an application program using a virtual database operation statement to operate on the database. The present invention relates to a virtual database system.

[0002]

2. Description of the Related Art When accessing a conventional database, different types of databases use different access methods. Therefore, an application program operating on one type of database does not operate on another type of database as it is. In order to solve this problem, a database (virtual database) operated by the application program operated by the operator is assumed between the application program operated by the operator and the database, and a conversion process of the database operation method is interposed. As a result, a virtual database system that allows access to databases having different operation methods by the same operation method is used.

In the above-described conventional virtual database system, as shown in FIG. 9, an execution module 101 of an application program using a virtual database operation statement (that is, a database operation statement handled by an operator) is used.
A virtual database adapter 102 is provided between the virtual database adapter 103 and the database 103, and the conversion from the virtual database operation method to the database access method is performed when the database is accessed.

[0004]

However, in the above-mentioned prior art, the creation of a virtual database adapter is
If the access method provided by the database is not highly versatile, there is a drawback that it is difficult. Therefore, it has been a problem to construct a virtual database method that can be realized even in a database that does not have a general-purpose access method for realizing a virtual database adapter without depending on the database. .

According to the present invention, the above object is achieved by realizing the construction of a virtual database adapter at a source program level, a general-purpose database access method is prepared, and a database operation statement is directly represented by a character string at the time of execution. It is an object of the present invention to provide a virtual database system that does not require a dynamic database operation statement processing function such as specification.

[0006]

In order to achieve the above object, the virtual database system of the present invention is adapted to a database for operating a source of an application program using a virtual database operation statement handled by an operator. Virtual database operation statement conversion means for generating in the source of the application program using the database operation statement,
This virtual database operation statement conversion means converts the input virtual
Application program using database operation statement
Lexical analysis, parsing, and intermediate tables for system sources
By creating and generating code,
Of application program using application operation statement
Is generated, and in the intermediate table creation processing,
After securing the command table area, the
The type is determined, and the command is a virtual database operation statement.
If, the table area corresponding to the type of command is
Necessary for code generation on the secured table.
Register the necessary information, and execute the virtual database operation
If it is not an essay, the above command being processed is
This virtual data is registered in the command table.
An execution module is obtained by compiling the source obtained by the conversion by the database manipulation statement conversion means, and the execution module accesses and operates the database.

[0007]

[0008]

In the code generation process of the virtual database operation statement conversion means, the type of the command is determined with reference to the command table, and when the command is a virtual database operation statement. Generates and outputs a database operation statement according to the type of command. If the command is not a virtual database operation statement, it outputs the contents registered in the command table as it is.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a virtual database system according to one embodiment of the present invention.

As shown in FIG. 1, a source 10 of an application program using a virtual database operation statement
(Hereinafter abbreviated as “source 10” as appropriate) is temporarily stored in the intermediate table 1 by the virtual database operation statement conversion unit 11.
2 and further converted to a source 13 of an application program using a database operation statement (hereinafter abbreviated as “source 13” as appropriate). From this source 13, the compiler 14 executes the application program execution module 15 using the database operation statement.
Is generated and becomes an execution module that accesses the database 16.

FIG. 2 is a flowchart showing the processing of the virtual database manipulation statement conversion means 11. Step S2
In step 1, a source 10 of an application program using a virtual database operation statement is read, lexical analysis processing is performed, and it is decomposed into basic elements in syntax.

In step S22, the syntax of the sequence of basic elements on the syntax obtained by the lexical analysis is analyzed, and a syntax error is processed, and the type and structure of the sentence are recognized. In step S23, an area of the intermediate table 12 is secured according to the syntax recognized by the syntax analysis, and information necessary for code generation is recorded in the intermediate table 12.

In step S24, it is determined whether or not the source 10 of the application program using the virtual database operation statement of the input file has been terminated. If the source 10 has been terminated, the process proceeds to step S25. Returning to step S21, step S21
Is repeated.

In step S25, referring to the information recorded in the intermediate table 12, a source 13 of an application program using a database operation statement is generated.

FIG. 3 shows a virtual database operation statement conversion means 1.
3 is a flowchart showing a process of an intermediate table creation step S23 in FIG. 2.

In step S31, a command table area is secured. In step S32, the type of the command currently being processed is determined. If it is a command of a virtual database operation statement, the process proceeds to step S34. If not, the process proceeds to step S33.

In step S33, the command being processed is registered as it is in the command table. Step S
At 34, a table area corresponding to the type of command is secured. In step S35, step S34
The information necessary for code generation is registered in the table corresponding to the type of the command secured in step (1).

FIG. 4 is a flowchart showing the flow of the code generation process in step S25.

In step S41, the intermediate table 1
2, a global declaration statement of the application program 13 using the database operation statement is generated. In step S42, the next command table is set as the current command table.

In step S43, the type of the command is determined, and if the command type is a virtual database operation statement, step S45
Otherwise, the process proceeds to step S44. Step S
At 44, the contents of the command registered in the command table are output as they are. In step S45, a database operation statement is generated and output according to the type of command.

In step S46, it is determined whether or not the command table is finished. If the command table is finished, the process is terminated. If there is another command table, the process returns to step S42, and the processes from step S42 are repeated. .

Thus, from the source 10 of the application program including the virtual database operation statement,
The intermediate table 12 is created by the lexical analysis processing, the syntax analysis processing, and the intermediate table creation processing, and the source 13 of the application program including the database operation statement is generated by the code generation processing.

According to the virtual database system of the present embodiment configured as described above, the source 10 of the application program using the virtual database operation statement is first converted into the source 13 of the application program using the database operation statement. Thereafter, the execution module 15 of the application program using the database operation statement is generated and operates on the database 16, so that the operator operates the database 16 as if the application program uses the virtual database operation statement. It can be operated in the same way as operating a database (virtual database) to be operated.

Next, the source 10 of the application program using the virtual database operation statement is changed to the source 13 of the application program using the database operation statement.
As an example of conversion to
A case where a program written in C language including SQL language is generated from a language program will be specifically described as an example.

FIG. 5 is an example of an application program source 10 including a virtual database operation statement.

Here, as the virtual database operation statement, an access statement 51, a prepare statement 52 for preparing access to the database, a for-each statement 53 for selecting data from the database, and a block representing the effective range of the for-each statement. Start statement 54, block end statement 55, end access statement 5 representing the end of the access statement
6 are used. The source 10 is a C language sentence except for the virtual database sentence.

FIG. 6 shows an example of the intermediate table 12, which is generated from the source 10 of the application program including the virtual database statement shown in FIG.
FIG. 2 is a diagram showing an outline of the second embodiment.

As shown in the figure, the connection of program sentences is represented by a command table 81, sentences other than virtual database sentences are registered as character strings in a variable-length area as they are, and the start address thereof is registered in a command table. I have. For the virtual database operation statement, a table corresponding to each statement is created, and information necessary for code generation is stored.

However, the block start statement 54, the block end statement 55 indicating the effective range of the for each statement, the end access statement 56 indicating the end of the access statement, and the like are apparent from the structure of the intermediate table 12 by referring to the pointer in the command table 81. Therefore, the corresponding command table is omitted.

FIG. 7 is an example of an application program source 13 including a database operation statement.

This is generated from the source 10 of the application program including the virtual database operation statement shown in FIG.
Have been translated into language sentences. As can be seen by comparing FIG. 5 and FIG. 7, the C language part is the same, and the virtual database operation statement is converted into a SQL language statement and a C language statement. More specifically, the for-each statement 53 in FIG. 5 and the block statements 54 and 55 representing the range are converted into the statement 71 in FIG.
No. 6 does not directly generate a sentence, but affects 71 sentences.

FIG. 8 shows the intermediate table 1 used in this embodiment.
2 shows the outline of the command table, 81 is a command table, 8
2 is a prepare table, 83 is a segment table, 8
4 is a prepare bite, 85 is a segment bite
, 86 is a foretable, 87 is a view table.
Bull, 88 is an at end table, 89 is a view key
Reference numeral 90 denotes an expression table, reference numeral 91 denotes an access table, and reference numeral 92 denotes a type table. These intermediate tables 1
2 is structured by pointer reference like the example of the intermediate table 12 shown in FIG. 6, and has a structure reflecting the structure of the source 10 of the application program using the virtual database operation statement.

[0034]

As described above, according to the present invention, the construction of a virtual database adapter for providing the same virtual database access method to an application program even when the database is different is realized at the source program level. There is no need for a dynamic database operation statement processing function such as preparing a database access method with a unique nature and directly specifying a database operation statement by a character string at the time of execution, and a database-independent virtual database method can be realized. This has the effect.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration diagram of an embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of a virtual database operation sentence conversion unit.

FIG. 3 is a flowchart illustrating an intermediate table creation process.

FIG. 4 is a flowchart illustrating a code generation process.

FIG. 5 is a diagram illustrating an example of a program including a virtual database operation statement.

FIG. 6 is a diagram illustrating an example of an intermediate table.

FIG. 7 is a diagram illustrating an example of a program including a database operation statement.

FIG. 8 is a diagram showing an outline of an example of an intermediate table.

FIG. 9 is a block diagram showing a configuration of a conventional virtual database system.

[Explanation of symbols]

Reference Signs List 10 Source of application program using virtual database operation statement 11 Virtual database operation statement conversion means 12 Intermediate table 13 Source of application program using database operation statement 14 Compiler 15 Application program execution module using database operation statement 16 Database

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiroshi Hirakawa 1-1-1 Minamiwatari-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Pref. KK Exa Co., Ltd. (56) References JP-A-61-100823 (JP, A JP-A-2-67682 (JP, A) JP-A-2-165239 (JP, A) JP-A-2-217963 (JP, A) JP-A-3-94374 (JP, A) 282826 (JP, A) JP-A-4-15753 (JP, A) JP-A-4-25942 (JP, A) JP-A-4-38563 (JP, A) (58) Fields investigated (Int. Cl. ^6, DB name) G06F 12/00 G06F 9/06

Claims (2)

(57) [Claims] In a virtual database system which enables access to databases having different operation methods by the same operation method, an application program adapted from a source of an application program using virtual database operation statements handled by an operator to a database to be operated. It includes a virtual database manipulation statements conversion means for generating a source of the application program using the database manipulation statements, the virtual database manipulation statements conversion means, the virtual database
Source of application programs using source operation statements
Lexical analysis processing to decompose
Parsing processing to analyze the syntax of lexical sequences, parsing
An intermediate table creation process that creates an intermediate table from the results
Database operation statement while referring to the intermediate table
Generate the source of the used application program
Code generation processing, and the intermediate table
After securing the command table area in the
The type of the command being processed is determined, and the
If it is a database operation statement, it depends on the command type.
And secure the area of the table
Register the information required for code generation in the
If the sentence is not a virtual database operation statement,
A virtual database system, wherein a command is directly registered in the command table . 2. The virtual database operation statement conversion means judges a command type by referring to a command table in a code generation process. If the command is a virtual database operation statement, the command And generating and outputting a database operation statement in accordance with the type of the command table. If the command is not a virtual database operation statement, the contents registered in the command table are output as they are. The virtual database system according to claim 1, wherein