JPH08221310A - Schema managing method - Google Patents

Abstract

PURPOSE: To provide a method to perform unitary management in a data-base system by relating fundamental definition information required for data management to additional definition information in which additional information not always required for the data management is represented in an arbitrary data type in the schema management of the database system. CONSTITUTION: A schema managing part 104 manages the fundamental definition information required for the management of data, and holds it in a schema database 103. A data managing part 105 manages the additional definition information 107 in which the additional information not always required for the data management is represented in the arbitrary data type, and holds it in a user database 106. A data identifier which identifies uniquely the data which holds the additional definition information 107 in the database system is held in the data which holds the fundamental definition information 102, and the data which holds the additional definition information in accordance with the fundamental definition information is acquired from the data identifier. In this way, the unitary management on relationship between the fundamental definition information and the additional definition information is performed in the database system.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to schema management of a database system, and expresses additional information to a data definition held in the schema by an arbitrary data type,
The present invention relates to a schema management method that associates basic definition information of the data definition with the additional information and enables unified management in the database system.

2. Description of the Related Art In a database system, in order to handle various data stored in a database, it is necessary to manage definition information indicating the structure and characteristics of each data, so-called schema information. A database user uses a database based on such definition information, but when the amount of definition information becomes enormous, it is difficult to grasp all the details of already defined information. Therefore, it is generally practiced to add a comment to the definition information so that the definition content can be easily grasped. Conventionally, for example, in relational database management system DB2, the document An Introduction to Data
base Systems, CJDate, Volume I, Fourth Edition,
As described in Addison-Wesley Publishing Company, 1986, you can add comments to the definition information of tables and columns that are components of the relational database schema. Definition information regarding tables and columns is held in tables SYSTABLES and SYSCOLUMNS provided by the DB2 system, respectively. These tables have column RE that holds string type data
There is MARKS and you can keep comments in this column. To add a comment, use the command COMMENT
This is done by setting the specified comment string in column REMARKS of table SYSTABLES or SYSCOLUMNS.
Refer to the tables SYSTABLES and SYSCOLUMN for comments
Do this by searching for S and referencing the value in column REMARKS.
Also, for example, in the object-oriented language Smalltalk-80,
As described in "Introduction to Smalltalk, ASCII Book Editor, ASCII Publishing Office, 1986", the structure and behavior of objects are defined when referring to definition information by a tool for browsing information in the system called a system browser. The operation for the class to
When the comment item is selected from the operation menu, the comment string for the class is displayed in the text view, and the comment string can be referenced and changed.

In the conventional method described above, the type of data that can be added as a comment is limited to the character string type. The data that represents a comment is also the data handled in the database, and it is preferable that it be expressed in any data type other than the character string type. If the operation of data with a more complicated structure can be applied, the comment expression capability Can be increased. However, the function of adding data with a more complicated structure other than the character string type as a comment is not in the schema management provided by the conventional database system, and it is necessary to add data with a complex structure to the definition information as a comment. , There was no choice but to use a separate management mechanism independent of schema management. The purpose of the present invention is to
In order to solve the above problems, in schema management of a database system, to provide a method for centrally managing in the database system by associating additional definition information represented by an arbitrary data type with basic definition information. is there.

To achieve the above object, the schema management method of the present invention manages a schema, which is a collection of definition information necessary for managing data handled by a database system, and the schema. In a database system having a schema management unit, basic definition information required for data management is held in the schema as basic definition information, and a definition target of the basic definition information is not necessarily required for data management. The additional information other than the basic definition information is retained as additional definition information by using data represented by an arbitrary data type defined in the schema, and the basic definition information and the additional definition information are associated with each other in the database. Centrally manage in the system. In particular, in an object-oriented database management system having an object identifier for uniquely identifying each object holding data handled in the database system in the system, the object-oriented database management system for holding the basic definition information. By holding the object identifier of the user-defined object that holds the additional definition information in the object provided by, the basic definition information and the additional definition information are associated with each other and are centrally managed in the database system. Further, in particular, in a relational database management system, between a table provided by the relational database management system for storing the basic definition information and an arbitrary table definable by the user for storing the additional definition information. Then, by performing an arithmetic operation between the tables, the basic definition information and the additional definition information are associated with each other and centrally managed in the database system.

According to the present invention, by associating the data created based on the data type defined by the user with the data holding the basic definition information, the data having the arbitrary data type is added to the basic definition information as the additional definition information. It can be associated and centrally managed in the database system. In an object-oriented database management system, an object holding basic definition information provided by the database management system is associated by holding an object identifier of an object holding additional definition information. In the relational database management system, the table for storing the basic definition information provided by the database management system and the table for storing the additional definition information are associated with each other by a calculation operation between the tables.

Embodiments of the present invention will now be described in detail with reference to the drawings. In addition, in all the drawings for explaining the embodiment,
Those having the same function are designated by the same reference numeral, and the repeated description thereof will be omitted. FIG. 1 is a block diagram showing the configuration of a database system according to an implementation example of the present invention.
Reference numeral 101 is a database management system for managing the entire database system, 102 is definition information of the data structure of various data handled in the database, and basic definition information necessary for managing the data, 103 is
Schema database for storing basic definition information, 104
Is a schema management unit that manages a schema that is a collection of basic definition information; 105 is a data management unit that manages data by referring to the basic definition information via the schema management unit;
Reference numeral 106 denotes a user database that stores data of database users created based on the basic definition information, 1
Reference numeral 07 is additional definition information created based on the basic definition information defined by the user, and reference numeral 108 is user data for storing data created based on the basic definition information defined by the user. FIG. 2 is a block diagram showing the overall configuration of a computer system according to an implementation example of the present invention. 20
1 is a central processing unit that controls the entire computer system,
Reference numeral 202 denotes a main storage device that holds each program of the database system, 203 denotes an external storage device that permanently stores data even when the database system is stopped, 20
Reference numeral 4 denotes an input device for inputting a request from a user, 205
Is a display device for displaying processing results to the user. FIG.
FIG. 6 is a block diagram showing an overall configuration of a computer system of a second embodiment to which the present invention is applied. In this example, unlike FIG. 2, the additional definition information 107A is held in the schema database 103 instead of the user database 106. As described above, the additional definition information is not limited to the schema database and the user database, and may be stored anywhere in the external storage device as long as it can be accessed from the database management system. FIG. 4 is an example of an object holding basic definition information when the schema management method of the present invention is applied to an object-oriented database system. Reference numeral 401 is an example of a class object that holds information regarding a class definition, which is a definition of a data structure, of the basic definition information. For the attribute NAME of the class object, the name of the class that the class object defines is set. In the class object 401, the character string CLASS is set for the attribute NAME, indicating that the class object holds the class definition information of the class (such a class is generally called a metaclass). Class object attributes
For ATTRIBUTES, the object identifier of the object that holds the information regarding the attributes defined in the class that is the definition target of the class object is held.
In the class object 401, the object identifier # oa2 is set for the attribute ATTRIBUTES, and the object 402 specified by the object identifier is
Indicates that the object holds the definition information of the attribute of the class definition (herein referred to as attribute object). The attribute object has attributes NAME, TYPE, NEXT, and COMMENT. However, in this example, other attributes not related to the description of the present invention are omitted and shown by. In the attribute object 402, a character string NAME and a type descriptor CHAR indicating a character string type are set for the attributes NAME and TYPE, respectively, so that the class object has an attribute with the attribute name NAME,
It is shown that the type of the value set in it is a character string. Also, for the attribute NEXT, the attribute object 4
The object identifier # oa3 of 03 is set, which causes the class object to be placed next to the attribute NAME
It is shown that it has the attribute indicated by the attribute object 403. Also, no value is set for the attribute COMMENT, which causes the attribute NAM of the class object to
It is indicated that the additional definition information is not associated with the basic definition information about E. Similarly, the attribute objects 403 and 404 indicate that the class object has the attributes ATTRIBUTES and COMMENT and the type of value set to them is an object identifier. FIG. 5 shows a class COMMENT defined by a class definition request from the user to hold additional definition information.
Is an example of a class object that holds definition information of. Here, the class COMMENT has the attribute REVISIO for indicating the version after the change, for the purpose of holding information related to the change of the basic definition information as additional definition information.
It is assumed that the user has made a class definition request by specifying N, the attribute EDITOR for indicating the person who made the change, and the attribute DATE indicating the date of the change. A class object 501 defines a class COMMENT of an object that holds additional definition information. Attribute objects 502, 503 and 504 allow class COMMENT
The object generated based on the definition of (comment object) is a character string for the attribute REVISION, an object identifier for the attribute EDITOR, and an attribute D.
Indicates that a date type value is set for each ATE. In such a format, the class of the object holding the additional definition information is defined by the user arbitrarily designating the data structure. FIG. 6 is an example in which an object holding basic definition information is associated with an object holding additional definition information. In this example, for the basic definition information about the class PERSON, a person named "Mike named version V01-02, October 20, 1994.
It is indicated that the additional definition information of "updated on the day" is associated. A class object 601 indicates the definition of the user-defined class PERSON. This class object 601 corresponds to an object holding the basic definition information regarding the class PERSON. Attribute object 6
02, 603 and 604, the class PERSON is
It is shown to have a string type attribute NAME, an integer type attribute AGE, and a string type attribute DEPT. The class object 601 holds the object identifier # oc1 for the attribute COMMENT. The object 605 specified by the object identifier # oc1 is a comment object having the structure of the class COMMENT shown in FIG. 5, and the attribute REVISION has the character string V01-02,
The object identifier # op1 of the object 606 having the structure of class PERSON is set in the attribute EDITOR, and the DATE type value Oct.20.1994 is set in the attribute DATE. Further, with respect to the object 606, the character string Mike is set in the attribute NAME, and the value according to the definition of the class PERSON is also set. These objects indicate the association between the basic definition information and the additional definition information described above. FIG. 7 shows the schema management method of the present invention.
It is an example of a table that holds basic definition information when applied to a relational database system. Here, an example corresponding to the information shown in the above-described application example to the object-oriented database system will be shown. 7
Reference numeral 01 is a system table SYSTABLES for storing table definition information. The table SYSTABLES is
Column NAME to show the table name, column CREATOR to show the name of the person who defined the table, column COLCOUNT to show the number of columns that make up the table,
Column COMMEN for indicating the key that identifies the row that holds the additional definition information to be associated with the table definition information
Have TKEY. Here, other columns not related to the description of the present invention are omitted. 702 is a table SYSTABLES
Where the table name is SYSTABLES,
The definer of the table indicates that the number of columns in the database system and the table is an integer (4 or more). 703 is a table that holds column definition information
A row showing the definition of SYSCOLUMNS and the table name is S
YSCOLUMNS, the table definer, indicates that the number of columns in the database system and table is an integer (4 or more). Reference numeral 704 is a row indicating the definition of the table PERSON, which indicates that the table name is PERSON, the name of the definer of the table is John, and the number of columns in the table is 3. Furthermore, the value # ck1 is set for the column COMMENTKEY, and the row holding the additional definition information is specified by using this value as a key. Reference numeral 705 is a row indicating the definition of the table COMMENT, and the table name is
COMMENT, the name of the definer of the table is John, and the number of columns in the table is 4. FIG. 8 is an example of a table SYSCOLUMNS that stores the definition of each column of the table shown in the data definition of FIG. 7. 801 is a table SYSCOLUMNS, where column NAME is the column name and column TBNAME is the table name and column that holds the column.
COLTYPE is the type of value to set for the column, the column
COMMENT KEY indicates the KEY that identifies the row that holds the additional definition information associated with the column definition information. FIG.
A table COMMENT that stores additional definition information, a table PERSON that stores person information, and a table SYSTAB
It is an example showing the result of JOIN of LES and table COMMENT. 901 is a table COMMENT and 902 is a table P
ERSON and tables SYSTABLES and SYSCOLUMNS
The table is constructed according to the information defined in.
A row 903 holds additional definition information, and # ck1 is set as the key value of the row. From this row and the row indicated by 704 in FIG. 7, for example, table SYSTA
By performing a relational algebraic join operation (JOIN) between BLES and the table COMMENT, a result such as 904 is obtained, and the information indicated by 903 is associated with the definition information regarding the table PERSON as additional definition information. You can FIG. 10 is a flowchart showing an outline of the user request process for the definition information operation on the database system. The request from the user is input from the input device. The input method may be, for example, a method of designating an operation target and activating an action of a required operation from a graphical user interface (GUI) displayed on a display device, or inputting an operation command and a value specifying the operation target. It may be a method. In short, any method can be used as long as the operation request and the operation target can be specified by the database system. The database system of the present embodiment is activated, and a request from the user is input through the input device (1001). In 1002,
It is determined whether the request input at 1001 is a setting request for additional definition information. If it is a request for additional definition information setting,
The additional definition information setting process is executed (1003), and 100
Repeat 1 and later. The process of setting the additional definition information will be described later. If it is determined in 1002 that the request is not the additional definition information setting request, it is determined whether the request is for additional definition information reference (1004). If the request is for additional definition information reference processing, the additional definition information reference processing is executed (100
5) and 1001 and subsequent steps are repeated. The process of referring to the additional definition information will be described later. If it is determined in 1004 that the request is not for additional definition information reference, it is determined whether the request is for cancellation of additional definition information (1006). If the request is for additional definition information cancellation processing, additional definition information cancellation processing is executed (1007), and steps 1001 and subsequent steps are repeated. The processing of canceling the additional definition information will be described later. If it is determined in 1006 that the request is not the additional definition information cancellation request, it is determined whether the request is a processing request of another database system, and processing corresponding to the request is executed. In FIG. 10, other requests are omitted and the termination request is determined (100
Only 9) will be described. If it is a termination request, the operation processing of the additional information relating to the definition information is terminated. If it is not a termination request, error processing is performed as an invalid processing request (for example,
It is displayed on the display device that there is an error), and 1001 and subsequent steps are repeated. FIG. 11 is a flowchart of the process of associating the basic definition information and the additional definition information when the user requests the database management system to set the additional definition information. Here, in the processing request for setting the additional definition information from the user, the basic definition information and the additional definition information to be operated are specified, and the database management system recognizes this specification and the data holding the basic definition information and the additional definition information. Data holding information shall be obtained. 11
In 01, an identifier that uniquely identifies the additional definition information included in the data holding the specified basic definition information (the object identifier in the case of an object-oriented database, the identifier of the table holding the additional definition information in a relational database) A key value is applicable. Hereinafter, referred to as a data identifier) is acquired, and based on this, additional definition information corresponding to the data identifier is acquired. For example, in object-oriented database systems, class PER
Class name PER to operate the basic definition information of SON
When the user specifies SON, the schema management section obtains the corresponding class object from the class name,
Get the class object Person (601 in FIG. 6).
The data management unit finds the object identified by the object identifier, and the attribute com of the class object
Based on the object identifier set in ment,
The comment object (605 in FIG. 6) corresponding to the class object Person is acquired. Also, for example, in relational database systems, tables
When the user specifies the table name'PERSON 'to operate the basic definition information of PERSON, the table PERSON
The row of the table SYSTABLES (704 in FIG. 7) that holds the basic definition information of the table and the row (903 of FIG. 9) of the table COMMENT that holds the corresponding additional definition information are
It is obtained by executing the following SQL statement. SELECT SYSTABLES. *, COMMENT. * FROM SYSTABLES, COMMENT WHERE SYSTABLES.NAME = 'PERSON' AND SYSTABLES.COMMENTKEY = COMMENT.KEY; In the previous example, in table SYSTABLES, column NA
The value set in the column COMMENTKEY in the row in which ME is 'PERSON' (704 in FIG. 7) is # ck1, and this value is the row in the table COMMENT that is the value of the column KEY (903 in FIG. 9). Therefore, the result is as shown by 904 in FIG. 1102 in 1101
Determines whether the additional definition information is obtained, and checks whether the additional definition information for the specified basic definition information already exists. When the additional definition information exists, the process goes to 1103, and the data holding the specified basic definition information is changed to hold the data identifier of the data holding the specified additional definition information, and the process ends. To do. For example, in the object-oriented database system, the user designates the comment object created on the main storage device 202 based on the definition of the class COMMENT as the additional definition information. Here, to change the data identifier of the specified additional definition information to be retained, change the object identifier assigned to the comment object on the main storage device specified by the user to the attribute comment of the class object Person.
May be changed to set to class object
The content of the comment object 605 specified by the object identifier # oc1 set in the attribute comment of Person may be changed so as to match the content of the comment object on the main storage device. The point is that the contents of the comment object specified by the object identifier set in the attribute comment of the class object Person should match the contents of the comment object on the main storage device specified by the user. However, here the attribute comment for multiple class objects
Set the same object identifier # oc1 for
When the comment object 605 is shared as a comment of a plurality of class definition information, changing the object identifier set in the attribute comment and changing the content of the comment object 605 have different meanings. In this case, when you want to change only the comment of the class object Person (when you want to change the correspondence between the basic definition information and the additional definition information), the class object Perso
Change the object identifier set in the n attribute comment. When it is desired to similarly change the comment object for all shared class objects (to change the content of the additional definition information itself), the content of the comment object 605 is changed. In this case, if it is possible to specify the change request for the correspondence between the basic definition information and the additional definition information or the change request for the content itself of the additional definition information, it is possible to perform clear processing. Also, for example, in a relational database system,
The user shall specify the row created in the table COMMENT as additional definition information. Here, in order to change so that the data identifier of the specified additional definition information is retained, the key value (value set in column KEY) assigned to the row holding the additional definition information specified by the user is changed to Row 704 that holds the definition of table PERSON
It may be changed to set it to the column COMMENTKEY of the table PERSON. You may change it to match the content of the row. In short,
Row 704 column that holds the definition of table PERSON
The content of the row identified by the key value set in COMMENTKEY should match the content of the row specified by the user. Here, if the same key value # ck1 is set for multiple columns COMMENTKEY of table definition information and row 903 is shared as a comment of multiple table definition information, change the key value set for column COMMENTKEY. And changing the contents of row 903 have different meanings. In this case, if you want to change only the comment of the table PERSON, change the key value set in the column COMMENTKEY of the row 704 that holds the definition of the table PERSON. When it is desired to similarly change the comments for all shared table definition information, the contents of row 903 are changed. In this case, if it is possible to specify the change request for the correspondence between the basic definition information and the additional definition information or the change request for the content of the additional definition information separately,
Can be treated explicitly. When the additional definition information does not exist in 1102, the procedure goes to 1104, and the data identifier of the specified additional definition information is held in the data holding the specified basic definition information, and the processing is ended. For example,
In the object-oriented database system, the object identifier of the comment object designated by the user is set in the attribute comment of the class object Person 601, as described in 1103 above.
Also, for example, in the relational database system, as described above in 1103, the key value of the row holding the additional definition information specified by the user is stored in the column C of the row 704 holding the definition of the table PERSON.
Set to OMMENT KEY. FIG. 12 is a flowchart of a process of referring to the additional definition information associated with the basic definition information when the user makes a request for additional definition information reference to the database management system. Here, in the request for additional definition information reference from the user, the basic definition information to be operated is specified, and the database management system recognizes this specification and the data holding the basic definition information has already been acquired. To do. At 1201, the data identifier of the additional definition information included in the data holding the designated basic definition information is acquired, and based on this, the additional definition information corresponding to the data identifier is acquired. As an example of this, as described above in the explanation of 1101, in the object-oriented database system, the class name PERSO
Comment object 60 when the user specifies N
5 is acquired, and in the relational database system, the row 903 of the table COMMENT is acquired when the user specifies the table name PERSON. At 1202, it is determined whether the additional definition information is acquired at 1201 and it is checked whether the additional definition information for the designated basic definition information already exists. If additional definition information exists, go to 1203 and 1201
The data holding the additional definition information acquired in step 1 is returned to the processing request side and the processing ends. When the additional definition information does not exist in 1202, the processing goes to 1204, and a processing for returning an error that “basic definition information without corresponding additional definition information is designated” is performed and the processing ends. FIG. 13 is a flow chart of a process of canceling the relationship between the basic definition information and the additional definition information when the user makes a request for canceling the additional definition information of the definition information to the database management system. Here, in the request for cancellation of additional definition information from the user, the basic definition information to be operated is specified, and the database management system recognizes this specification and the data holding the basic definition information has already been acquired. To do. 1301
The data identifier of the additional definition information included in the data holding the designated basic definition information is acquired, and based on this, the additional definition information corresponding to the data identifier is acquired. As an example of this, as described in the explanation of 1101, the comment object 605 is acquired when the user specifies the class name PERSON in the object-oriented database system, and the table name is acquired in the relational database system. PERSO
When N is specified by the user, the row 903 of the table COMMENT is acquired. In 1302, it is determined whether the additional definition information is acquired by 1301 and it is checked whether the additional definition information for the specified basic definition information already exists. If additional definition information exists, 1303
Then, the data identifier of the specified additional definition information is deleted from the data holding the basic definition information, and the process ends. For example, in the object-oriented database system, the attribute comment of the class object Person601
Invalidates the setting value of. Further, for example, in the relational database system, the setting value of the column COMMENTKEY of the row 704 holding the definition of the table PERSON is invalidated. If the additional definition information does not exist in 1302, the processing proceeds to 1304, and processing for returning an error that "basic definition information without corresponding additional definition information is specified" is performed, and the processing ends.

As described above, according to the present invention,
Regarding the definition information in the schema, the basic definition information and the additional definition information having an arbitrary data structure can be associated and centrally managed in the database system.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing the configuration of a computer system according to an implementation example of the present invention.

FIG. 3 is a block diagram showing the configuration of a computer system according to a second implementation example of the present invention.

FIG. 4 is a block diagram showing an object that holds basic definition information when the schema management method of the present invention is applied to an object-oriented database system.

[Figure 5] Object class that holds additional definition information
Block diagram showing the class object that defines COMMENT.

FIG. 6 is a block diagram showing an example in which an object holding basic definition information is associated with an object holding additional definition information.

FIG. 7 is a block diagram showing a table storing basic definition information when the schema management method of the present invention is applied to a relational database system.

FIG. 8 is a table that stores the definition of each column of the table
Block diagram showing an example of SYSCOLUMNS.

FIG. 9: COMMENT table that stores additional definition information
And a block diagram showing an example of the result of a JOIN of a table PERSON and a table SYSTABLES and a table COMMENT that store person information.

FIG. 10 is a flowchart showing an outline of user request processing for definition information operation with respect to a database system.

FIG. 11 is a flowchart of processing for associating basic definition information with additional definition information.

FIG. 12 is a flowchart of a process of referring to additional definition information associated with basic definition information.

FIG. 13 is a flowchart of processing for canceling the relationship between the basic definition information and the additional definition information.

[Explanation of symbols]

 101 ... Database management system 102 ... Basic definition information 103 ... Schema database 104 ... Schema management unit 105 ... Data management unit 106 ... User database 107 ... Additional definition information 108 ... User data

Claims (3)

[Claims] 1. A database system having a schema, which is a collection of definition information necessary for managing data handled by the database system, and a schema management unit for managing the schema, and is a basic data management system. Definition information is held in the schema as basic definition information, and additional information other than the basic definition information that is not necessarily required for data management regarding the definition target of the basic definition information is defined in the schema as additional definition information. The schema management method is characterized in that the data is stored by using data represented by an arbitrary data type, and the basic definition information and the additional definition information are associated and centrally managed in the database system. 2. An object-oriented database management system having an object identifier for uniquely identifying each object holding data handled in a database system in the system, said object-oriented for holding said basic definition information. 2. The basic definition information and the additional definition information are associated with each other by holding an object identifier of a user-defined object that holds the additional definition information in an object provided by a database management system. Schema management method. 3. In a relational database management system, a table provided by the relational database management system for storing the basic definition information and an arbitrary table definable by the user for storing the additional definition information. 2. The schema management method according to claim 1, wherein the basic definition information and the additional definition information are associated with each other by performing an arithmetic operation between the tables.