JPH01248233A - Data base retrieving device - Google Patents

Abstract

PURPOSE:To enable retrieval by the minimum with respect to a storage device by executing a management information processing without storing a result, when many record groups concerned exist in an initial stage of selection in a process in which the record concerned is being selected. CONSTITUTION:With respect to an object to be selected, a selecting and retrieving command is issued and defined as a virtual file 33, and thereafter, a retrieval condition which is designated successively becomes a condition adding designation and a condition is added to the virtual file 33, by which the management information is selected, and by minimizing a storage device 31, the selection and retrieval of a data base are executed. That is, at the time of executing the data retrieval to a large capacity file, in case of detecting a record for satisfying some condition, the condition is not designated at a time but designated successively, and when many record groups concerned exist in the initial stage of reduction in a process in which the record concerned is being selected, an on-management information processing is executed without storing a result. In such a way, the retrieval can be executed by the minimum with respect to the storage device 31.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a database search device.

(Prior Art) In order to narrow down a search to a database, it is done by issuing a search and storage command with search conditions given to the target file. As a result, control is transferred from the command decoding section to the search processing section, and after searching for a record that satisfies the conditions, a new storage file area is secured in the recording device and all records are stored in that file. The stored file is registered in the information file as a file with a name derived from the original file according to a certain rule, and can thereafter be searched as a normal file. Therefore, in order to narrow down the search, the process of issuing a search command specifying all the search conditions is repeated for the derived file.

In addition, returning to the previous state can be done by processing files that have names that follow certain rules. In order to obtain the final record group, it is also possible to similarly issue an all-retrieval command to the relevant file.

(Problem to be Solved by the Invention) According to the conventional example described above, when the narrowing process is performed once, one new storage file is required, and as the number of narrowing processes increases, the number of files increases proportionally. The area within the storage device that is exclusively used by the user increases.

The present invention was made based on the above circumstances, and when finding records that satisfy a certain condition in a data search, instead of specifying the condition one time, it narrows down the corresponding records by specifying the condition one by one. It is an object of the present invention to provide a database search tuff that can be processed with a minimum storage capacity in order to obtain a group of records.

[Structure of the Invention] (Means for Solving the Problems) The present invention consists of a file composed of a group of data records having fields to be searched, and an information file containing management information such as record attributes in the file. A storage device in which the database is stored, a command decoding unit that interprets commands related to database operations, a search processing unit that executes a search command with specified search conditions to search for and output the corresponding data record, and file attribute definitions. and a file definition section that defines some records in the file as virtual files, and after searching the target file for a group of records that satisfy a certain search condition, the database search processing means The configuration is such that the target record is obtained by sequentially repeating the search process by giving further conditions to the resultant record group, narrowing down the record group that satisfies the condition, and the virtual file processing of the file definition section mentioned above. A mechanism for adding and deleting search conditions is provided in the section, and the target file is processed as a virtual file in response to a narrowing search command.
Narrowing down search conditions that are specified sequentially are interpreted as condition addition commands to the virtual file, a condition deletion command is issued to restore the status, and further narrowing down conditions are sequentially specified to confirm and output the narrowed down record group. The configuration is such that an all-item search is performed for the added virtual files, and a narrowed search is performed only by updating the management information.

(for production) In the file definition section of the database search device.

A condition addition mechanism that processes a command to add a narrowing condition to a virtual file definition condition as an AND condition, and a condition deletion mechanism that carefully returns the narrowing down to its previous state and deletes the previous search condition from the virtual file definition condition. By providing , a narrowing search command is issued for the narrowing target definition first, and after defining it as a virtual file, the search conditions that are specified sequentially can be used to add conditions to the virtual file as condition addition specifications. By doing this, you can narrow down the management information, minimize the storage space, and narrow down the database search t? Do 4 lines.

Due to this, when performing a data search on a large file, if you want to find a record that satisfies a certain condition, instead of specifying the condition one time, specify it sequentially and narrow down the records that meet the criteria. If there are a large number of applicable record groups at the initial stage of narrowing down, the results are not stored and processing is performed on the type-embedded information, making it possible to execute the search with minimal time t11.

(Example) Hereinafter, examples of the present invention will be described in detail using the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, 1 is a terminal device through which a database user inputs search commands and displays all search results.

Reference numeral 2 denotes a search device which operates on a database 3, which will be described later, according to a search command. 3 is a database;
The information file 31. is stored on a direct access mass storage device. File 32. It is composed of virtual files 33. Reference numeral 21 denotes a command decoding unit, which decodes the command and passes control to subsequent processing units. 22 is a file definition section, which defines virtual files, adds conditions, and deletes them. Line 4 shows connection 2 at the time of file definition. 33 is a search processing unit that searches for records that satisfy all conditions and outputs the corresponding records. Line 5 shows the connection when searching, and line 6 shows the connection when outputting the results.

FIG. 2 is a flowchart showing the operation of the embodiment of the present invention. Below, we will use the entire flowchart shown in Figure 2 to
The operation of the embodiment of the present invention shown in the figure will be described in detail.

In search device f2, if file 32 of database 3 is to be narrowed down, file 3 is searched from terminal it1.
A narrowing search command is issued to the 2VC along with the search condition (first narrowing condition) and the virtual file name 33. The issued command is determined by the command decoding section 21 in step I in FIG. In this case, since the command is a definition, control is transferred to the file definition section 22, and further, in step (2), it is determined that it is a definition, and the virtual file definition is executed.

At this point, a group of records that satisfy the conditions specified for the file 32 are registered in the information file 31 as a virtual file 33.

When specifying narrowing conditions sequentially, a condition addition command is issued to the virtual file 33 together with the additional conditions. At this time, step I and step Ill are fully executed with the addition of flow conditions. In the condition addition process, search for the information of the virtual file 33 from the information file and narrow it down to the condition condition i AN
Add with condition D. At this time, the virtual file 33 represents a record group of the file 33 that satisfies the first condition and the next specified nine conditions.

If you want to continue squeezing, repeat the above process. Also, in order to return to the previous state, a condition deletion command is issued. When the narrowing down is completed or when the current state of the narrowing down is to be viewed, an all-file search command is issued to the virtual file 33 from the terminal device v1. The issued command is determined by the command decoding section 211/C in step (2), and in this case, since the command is a search, control is transferred to the search processing section 23.

Therefore, in step (2), the target file is determined to be a virtual file, and the entire search for the virtual file 33 is executed.

Since the target file 33 is a virtual file, the definition information is extracted from the information file 31, expanded to the search for the original file 32, searched for a record group of the file 32 that satisfies the current conditions, and the result is sent to the terminal device according to route 6. View records.

[Effects of the Invention] As explained above, according to the present invention, when searching for data in a large file, when finding a record that satisfies a certain condition, the condition is not specified one after another, but sequentially. In the process of specifying and narrowing down the applicable records, if there are a large number of applicable records at the initial stage of narrowing down, the results will not be stored and will be processed based on the management information.
It becomes possible to execute searches using a minimum amount of storage device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a flowchart showing the operation of the embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Terminal device, 2... Search device, 3... Database, 21... Command decoding section, 22... File definition section, 23... Search processing section, 3... Information File, 32...File, 33...Virtual file.

Claims (2)

[Claims] (1) A storage device that stores a database consisting of a file consisting of a group of data records with fields to be searched and an information file containing management information such as record attributes in the file, and interprets instructions related to database operations. a command decoding part that executes a search command with specified search conditions, searches for and outputs the corresponding data records, and a file definition part that defines file attributes and some records in a file as virtual files. The database search processing means searches a target file for a record group that satisfies a certain search condition, and then searches the resulting record group by applying further conditions. A database search device that narrows down a group of records that satisfy a condition and obtains a desired record by sequentially repeating processing. (2) A search condition addition and deletion mechanism is provided in the virtual file processing section of the file definition section, and in response to a narrowing search command, the target file is processed as a virtual file, and the narrowing search conditions specified in sequence are , interprets it as a condition addition command to the virtual file, issues a condition deletion command to restore the state, and further adds all the conditions to the virtual file to which the narrowing conditions have been sequentially added in order to confirm and output the narrowed down record group. 2. The database search device according to claim 1, wherein the database search device performs narrowing search by only updating management information.