JP2001273178A - Method and system for controlling database - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system capable of adding processing of a record corresponding to the meaning of the linking order of the record in a network-type database when providing an operation interface using an SQL language in a network-type database system. SOLUTION: Information on the storing order of record data is provided in definition information on coordinating of a table to be dealt with by an SQL language and record data in the network-type database. When performing adding processing of the record, the adding position of the record is decided in accordance with information concerning this storing order.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a database control device and system, and more particularly, to a database control device and system that allows a network type database to be referenced and updated by an SQL language interface.

[0002]

2. Description of the Related Art Conventionally, network-type databases have been widely used. However, since data is operated on a record basis, reference and update of the database must be described procedurally based on operation on a record basis. Some aspects are difficult to use. On the other hand, a relational database is based on data manipulation on a table basis and can provide a relatively easy-to-use interface. In addition, SQL, which is a standard search language for relational databases, is not limited to relational databases, but has come to be widely used as an interface for operating table format data. Accordingly, a method has been considered in which a network type database can be referenced and updated using an SQL language interface. For example, in a relational access method for a network-type database described in Japanese Patent Application Laid-Open No. 06-282576, definition information for associating record data of a network-type database with a table is provided, and SQL is used for the table associated with the table. Operations that can be performed.

[0003]

The network type database has a data structure in which a plurality of records are linked by pointers. Therefore, not only the field values in the record but also the link order of the record may have meaning. For example, in a network-type database that has applicant information records in which the link order of records is the order of reception, if this link order is changed, a database consisting of a set of records with the same contents will have different reference and update procedures. turn into. For example,
Considering the process of "outputting data on the first ten applicants of reception", if the link order is the reception order, it is sufficient to sequentially read ten records according to the link, but if the order is changed, this response Is lost. If the entry number is stored as field data in the record, the record can be output by performing a conditional search using the entry number as a condition. However, a search is performed for all applicant information records, and the efficiency is greatly reduced. Therefore, when a record is added to such a database, it must be able to be added at a position along the meaning of the link order of the record. However, in the above conventional technology, since the SQL language does not specify the order of the rows of the table, it is not possible to specify the position of the additional record in the database when a row is added to the table by the INSERT statement. An object of the present invention is to provide a network type database system with an operation interface using an SQL language, a database control device capable of adding records corresponding to the meaning of the link order of records in a network type database, and It is to provide a system.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a database system capable of referencing and updating a network-type database with an SQL language interface. The information on the storage order of the record data is provided in the definition information on the association of the record data. Then, when performing the record addition processing, the record addition position is determined according to the information on the storage order. Here, the information on the storage order is given as information including a field name for specifying the order and a type of the order shown in ascending or descending order of the field value. With the above configuration, the addition of a record whose addition position can be specified by the operation interface using the SQL language of the network type database is realized.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the database system of the present invention. The database system according to this embodiment includes an input / output device 1, an operation request receiving unit 2, an operation request conversion unit 3, a database 4, and a table definition storage device 5. The database 4 includes record data 41 and a database definition 42. The table definition storage device 5 includes a record = row correspondence definition 51 and a record storage order definition 52. The operation request converter 3 and the table definition storage device 5 constitute a database control device 7.

First, the configuration of the database 4 will be described. It is assumed that a network type database composed of records having a parent-child relationship as shown in FIG. FIG. 2 illustrates an application information record as a parent record and an applicant information record as a child record. FIG. 3 shows an example of the contents of the record data 41 in the database 4 in this case. In FIG. 3, the application round information record has four fields of “round, application start date, application end date, total number of applications”, and the applicant information record has four fields of “name, address, telephone number, entry date and time”. Has two fields.
In addition, each applicant information record has a link (pointer association) directly or indirectly through another child record with the application information record of a certain round. Multiple applicant information records for the same round have links in such a way as to form a chain between them and the corresponding round information record. The parent record has a key field, and access to the parent record is mainly performed by specifying the value of the key field. In the example of FIG. 3, the “pass” field of the application turn information record is a key. On the other hand, access to a child record is performed by directly or indirectly following a link from a parent record having a link. For example, the "name" in FIG.
“Appendix” is “No. 1” in the applicant information record
It is possible to arrive from the application round information record of “time” through the applicant information record of “name” of “Yamakawa xx”. The database definition 42 describes the field configuration and link structure as described above. FIG. 4 is an example in which the database definition 42 of the database 4 shown in FIGS. 2 and 3 is described. The record name and the type of parent and child, the name of a field included in the record, the key field of the parent record, and the parent record name associated with the child record are defined.

[0007] On the other hand, the table definition storage device 5 stores information relating to correspondence for treating record data having a network structure of the database 4 as a virtual table. The record = row correspondence definition 51 indicates which field of the record data corresponds to the field of the row data constituting the table.
FIG. 5 is an example of a record = row correspondence definition 51 when a table is configured based on the records of the database 4 shown in FIGS. 2 and 3. Table name 51 of the table to be configured
1. Record type name (selected record type) 512 of a record constituting a table, field name (row field) 513 constituting a row in a table, and record data type name (record type) 514 and field corresponding to the row field First name (record field) 5
15 are defined.

[0008] The record storage order definition 52 indicates rules regarding the storage order of records in the database 4 corresponding to the rows in the table. FIG. 6 shows records of the database shown in FIG. 2 and FIG.
5 is an example of a record storage order definition 52 when tabulated using a row correspondence definition 51; A rule type (order type) 521 relating to the storage order of records and items for determining its contents (here, field names for determining the order and ascending / descending order) 522 are defined. As a key field for determining the order, a plurality of fields and their ascending / descending order may be designated as “first key, second key, etc.”. Here, the storage order is specified by specifying the field in the record and the ascending order / descending order. However, if there is a procedure that can determine the addition position from the record data to be added, it is added to the new order type. It is possible to set and use as.

Next, the database processing in the SQL language interface will be described. In this process, an inquiry is made by looking at the record data of the network type database as a virtual table according to the contents of the table definition. FIG. 7 shows the correspondence between the database 4 having the record data of FIG. 3 and the virtual table 71 when the database 4 is viewed in accordance with the record = row correspondence definition 51 of FIG. The query by the SQL sentence is processed as to such a virtual table 71. First, the flow of the database reference process will be described. When an SQL sentence for table data reference is input through the input / output device 1, the sentence is passed to the operation request receiving unit 2. The operation request receiving unit 2 issues an SQL statement processing request to the operation request converting unit 3. The operation request conversion unit 3 converts a request relating to table data reference of an SQL statement into an access command to the record data 51 for the database 4. At this time, the row in the table 71 and the record in the database 4 are the record of the table definition storage device 5 = the row
1 are associated. The database 4 receiving the command returns record data corresponding to the command to the operation request conversion unit 3. The operation request conversion unit 3 expands the record data into table data according to the record = row correspondence definition 51. At this time, the table data is configured as a set of rows in which a row of a record having a parent-child relationship link is connected between one type of parent record and one type of child record in the network type database. . Then, the operation request conversion unit 3 outputs the developed table data to the input / output device 1 through the operation request reception unit 2. The above is the process of referring to the database.

Next, the flow of the database update process will be described. When an SQL statement for updating table data is input through the input / output device 1, the sentence is received by the operation request receiving unit 2 (similar to the case of referring to table data),
This is an SQL statement processing request to the operation request conversion unit 3.
The operation request conversion unit 3 sends a request for updating the table data of the SQL statement to the record data 4
1 access command. Again, the rows in the table are associated with the records in the database according to the record = row correspondence definition 51. However, if the updated content requires the addition of a child record, the record storage order definition 52
, The record addition position is determined. The database 4 receiving the command updates the record data according to the command, and reports the result to the operation request conversion unit 3. Then, the operation request conversion unit 3 reports the completion of the update process to the input / output device 1 through the operation request reception unit 2. The above is the database update process. A feature of the present invention is that, when the operation request conversion unit 3 converts an SQL statement for updating table data into an access command for the database 4, a record addition position is determined according to the record storage order definition 52.

Next, the details of the processing related to the update accompanied by the addition of the child record will be described. FIG. 8 is a flowchart of a process for adding a record to the database 4 using an INSERT statement of a query by SQL. First, the input I
The arrangement of the field values of the NSERT statement is associated with the record data to be added (step 801). SQL I
The NSERT statement is “INSERT INTO <table name> VALUES (<
Field value list>) ", and the field value list therein is associated with the field value of the record data to be added. In the case of adding a parent record, the row field whose record type corresponds to the parent record in the record = row correspondence definition 51, and in the case of adding a child record, the record type is also the record type in the record = row correspondence definition 51. Corresponds to the line field corresponding to. Next, it is determined whether or not a parent record needs to be added (step 802). The condition for the determination is that "is there a record in the parent record that already has the same value in the key field?" If the parent record needs to be added (Y in step 802), the record data for adding the parent record created by the association in step 801 is added to the database (step 803). Since the addition of the parent record is not tied to the link chain, there is no need to specify the addition position. On the other hand, if it is not necessary to add a parent record (N in step 802), this process is skipped. Subsequently, it is determined whether or not a child record needs to be added (step 804). The condition for the determination is that “whether the table has a field corresponding to the child record”. If a child record needs to be added (Y in step 804), the position to be added is determined according to the specification of the record storage order definition 52 (step 805), and the record for adding the child record created by the association in step 801 is created. The data is added to the database (step 806), and the process ends. On the other hand, if it is not necessary to add a child record (N in step 804), the process ends. The above is the record adding process.

FIG. 9 is a detailed flow chart of the processing for determining the addition position of the child record in the record addition processing described in FIG. First, the first child record is searched from the chain of the parent record (step 901). The parent record can be searched by its key field (for example, “recurring” in the database contents of FIG. 7), and a child record can be searched by a link from that. At this time, if the next child record cannot be retrieved at the end of the chain (step 9).
02, Y), the record data addition position is determined at the end of the chain (step 903), and the process ends.
On the other hand, if the next child record can be retrieved (step 90)
(N in 2), and proceed to step 904 as it is. Next, the record data to be added and the retrieved child records are stored in the “field” and “ascending /
In accordance with "descending order", it is determined whether or not the retrieved child record is in an order after the record data to be added (step 904). When “ascending order” is specified, if the value of the specified “field” of the record data to be added is smaller than the searched child record, the searched child record is in the last order. When “descending order” is specified, if the value of the specified “field” of the record data to be added is larger than the searched child record, the searched child record is in the last order. Here, when a plurality of order keys are specified in the record storage order definition 52, when the field value is equal in the comparison with a certain key (the nth key), the comparison with the next key (the n + 1th key) is performed. I do. If the retrieved child record is in the order after the record data to be added (Y in step 904), the position of the record data to be added is determined before the child record (step 90).
5), end the processing. On the other hand, if the searched child record is not in the order after the record data to be added (N in step 904), the next child record in the chain is searched (step 906), and the process returns to the end of the chain determination (step 902). . The above is the processing for determining the addition position of the child record.

FIG. 10 shows the record storage order definition 5 shown in FIG.
2 and 71 in the “Application Information” table in FIG.
RT INTO application information VALUES ('1st', 'Kimura xx', 'Kita-ku, Tokyo', '03-8765-xxxx', '1999/10/12 14:25:24') This shows how the statement tried to add a row (including adding a record in the database). Child records (records of applicant information) are added to the chain corresponding to the row data added in the virtual table 71. Lines and records added in the figure are shaded,
The links replaced accordingly are indicated by thick arrows. Since the parent record (record of the application round information) whose key field “round” value is “1st” already exists,
No parent record is added. Adding child records
The value of “second” is performed in the chain of the “first” parent record. The addition position in the chain corresponds to the entry “date and time” according to the specification of the item 522 (“field” and “ascending / descending order”) of the record storage order definition 52 in FIG.
Is determined to be “ascending order”.

[0014]

As is clear from the above description, according to the present invention, the definition information relating to the correspondence between the table handled in the SQL language and the record data of the network type database includes information on the storage order of the record data,
For details, a set of a field name for specifying the order and a type of order indicated in ascending or descending order of the field value, etc. is provided, and when performing the record adding process, the record adding position is determined according to the information on the storage order. By deciding, the record whose addition position can be specified by the operation interface using the SQL language of the network type database is realized. As a result, it is possible to obtain an effect that an operation corresponding to the meaning of a record unique to a network-type database can be performed while an operation interface using the SQL language itself is used in a relational database.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a database system according to the present invention.

FIG. 2 is a diagram showing a parent-child relationship between records in a network database.

FIG. 3 is a diagram showing an example of the contents of record data in a network database.

FIG. 4 is a diagram illustrating an example of a database definition of a network-type database.

FIG. 5 is a diagram illustrating an example of a record = row correspondence definition in a table definition storage device.

FIG. 6 is a diagram illustrating an example of a record storage order definition of a table definition storage device.

FIG. 7 is a diagram showing correspondence between record data of a database and a virtual table.

FIG. 8 is a flowchart of a process of adding a record to a database in SQL (INSERT statement).

FIG. 9 is a detailed flowchart of a process of determining a child record addition position in a record addition process.

FIG. 10 is a diagram illustrating an example of changes in table data and record data when an attempt is made to add a record to a database (add a row to a virtual table).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... I / O device, 2 ... Operation request reception part, 3 ... Operation request conversion part, 4 ... Database, 5 ... Table definition storage device,
7 ... Database controller, 41 ... Record data, 4
2 ... database definition, 51 ... record = row correspondence definition,
52: Record storage order definition.

Claims (4)

[Claims] 1. A database control device for referencing and updating a network-type database with an SQL language interface, wherein record data is stored in definition information relating to correspondence between a table handled in the SQL language and record data of the network-type database. A database control device comprising storage means for holding definition information on an order. 2. The database control apparatus according to claim 1, further comprising: means for determining a record addition position in accordance with definition information on a storage order of the record data when performing a record addition process. 3. The method according to claim 1, wherein the definition information relating to the storage order of the record data includes a field name for specifying the order and a type of the order shown in ascending or descending order of the field value. Database controller. 4. A system for referencing and updating a network-type database with an SQL language interface, wherein the definition information relating to the correspondence between a table handled in the SQL language and record data of the network-type database relates to the storage order of record data. A database system comprising storage means for holding definition information.