JP3907295B2 - Information retrieval apparatus and method, and computer-readable storage medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an information search apparatus and method, and more particularly to an interface between a heterogeneous database integration system or a database (hereinafter abbreviated as DB) system and a searcher and a search method thereof.
[0002]
[Prior art]
With the spread of computer networks, it has become possible to access various DBs from personal terminals. DBs accessible from the network are managed by management systems written in various languages. If data with different formats and meanings stored in these various DBs can be handled in a unified manner, the utility value of the DB connected to the network will be even higher. A technology for accessing a computer system constructed in a different language or environment without the user's awareness is provided as a multimedia DB, a distributed computing system, or the like.
[0003]
For example, the technique described in Japanese Patent Laid-Open No. 7-65032 is realized as follows. However, in the following, an inquiry language that can be used on the user terminal is referred to as a standard language, and a data representation format there is referred to as a standard format. A multi-database system (hereinafter abbreviated as MDB system) has the following libraries and tables in advance.
(1) Library for language conversion between the standard language used in the user terminal and the DB language used in the search target database
(2) Data conversion library that converts data expressed in the standard format into the representation format specific to each DB, or reverse conversion
(3) Management table for associating DB names with corresponding language conversion libraries and data conversion libraries [0004]
In the above technique, a user describes a search target DB name and a query in a standard language. Then, the system acquires the numbers of the language conversion library and the data conversion library corresponding to the target DB using the management table from the target DB name. Then, the query described in the standard language by the user is converted into the language used in the target DB by using the language conversion library, and transmitted to the target DB. When the result for this inquiry is transmitted from the target DB, the system converts it to a standard format using the data conversion library and transmits it to the user.
[0005]
As another implementation method, the technique described in Japanese Patent Laid-Open No. 5-342123 implements a command transfer method for a network system. In the system realized here, the command sequence input by the user is analyzed, the system on the computer network for executing the requested processing is determined, and the command specified by the system is specified as the command supported by the system. Can be converted. Such a system can be applied to an MDB system if the command is a query statement and the target system is a DB management system.
[0006]
[Problems to be solved by the invention]
However, the conventional method has the following problems.
[0007]
First, in the conventional method, when the script written by the user is evaluated in the application order (applicative-order), the procedure and data that do not contribute at all to obtain the final result requested by the user are evaluated (executed). End up.
[0008]
In the case of a normal program, since the compactness of the interpreter is more effective than the increase in the amount of calculation due to the execution of unnecessary evaluation, such application order evaluation tends to be preferred. However, in a distributed DB integrated system, the amount of network traffic becomes a critical evaluation item, so it is desirable to avoid using communication channels to evaluate unnecessary procedures and data as much as possible.
[0009]
Further, the commercial DB provides an optimization mechanism that rearranges the evaluation order of queries that combine partial queries in the order in which the processing speed is the fastest. However, if the MDB system evaluates partial queries in the order of application, the optimization mechanism provided by each DB cannot be used.
[0010]
[Means for Solving the Problems]
In order to solve the above-described problem, according to the present invention, an information retrieval apparatus that can use a plurality of databases, an expansion means for expanding an input search query in script format into one or more primitives including user primitives; For each developed primitive, a database in charge of evaluation is selected, and database information for evaluation in which the database is specified and primitive information in which a further primitive to be evaluated for evaluation of the primitive is registered. A construction means, an evaluation means for evaluating each primitive using a database in charge of evaluation of the primitive with reference to the evaluation person in charge database information, and the user primitive by the evaluation means with reference to the primitive information. Of primitives to be evaluated for evaluation of And a control means for controlling so as to evaluate the people, the evaluation result of the user primitive, and output means for outputting as a result of the search query.
[0011]
According to another aspect of the present invention, there is provided an information search method in an information search apparatus including an expansion means, a construction means, an evaluation means, a control means, and an output means, and is capable of using a plurality of databases. The expansion means expands the input script-type search query into one or more primitives including user primitives, and the construction means selects a database in charge of evaluation for each expanded primitive. A construction step of registering database information for evaluating the database for identifying the database and primitive information for identifying further primitives to be evaluated for evaluating the primitive, and the evaluation means refers to the database information for the evaluation And evaluate each primitive using the database responsible for evaluating the primitive. A control step in which the control means refers to the primitive information so that the evaluation means evaluates each primitive to be evaluated for the evaluation of the user primitive; and the output means And an output step of outputting the evaluation result of the user primitive as a result of the search query.
[0012]
Further, according to another aspect of the present invention, an expansion step of expanding an input script-type search query into one or more primitives including user primitives on a computer-readable storage medium. For each primitive, a construction step of selecting a database in charge of evaluation and registering database information of an evaluation person specifying the database and primitive information specifying a further primitive to be evaluated for evaluation of the primitive; An evaluation step of evaluating each primitive using a database in charge of evaluation of the primitive with reference to the evaluation person database information, and evaluation of the user primitive by the evaluation means with reference to the primitive information. Each of the primitives to be evaluated for And a control step of controlling so as to evaluate the results of evaluation of user primitive, stores information retrieval program characterized by executing the output step of outputting as a result of the search query.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
(Embodiment 1)
FIG. 1 is a diagram showing a functional configuration of a heterogeneous database integration system according to an embodiment of the present invention. Each unit of the device may be a device including a dedicated program memory or processor as long as it realizes the functions described below, or a plurality of functional units are connected to a ROM or disk memory by the same CPU. It may be realized by executing each function program stored in the above or by executing a control program for controlling specific hardware corresponding to each function.
[0014]
Hereinafter, each part of FIG. 1 will be described.
[0015]
<Heterogeneous DB integration system 101>
The heterogeneous DB integration system 101 includes a communication control device 110, a primitive interpretation device 111, a DB selection device 112, a resource table 113, a library 114, a parameter table 115, and an LDB property table 116. Details will be described later. The resource table 113 is used by the DB selection device 112, and the library 114, the parameter table 115, and the LDB property table 116 are used by the primitive interpretation device 111.
[0016]
FIG. 6 is a block diagram showing a hardware configuration of the heterogeneous DB integration system 101.
[0017]
In the figure, reference numeral 601 denotes a CPU that controls each part of the system via a bus and executes various programs. Reference numeral 602 denotes an I / O that receives a search query from a user or issues a query to a database and receives the result. Reference numeral 603 denotes a ROM that stores fixed data and fixed programs. Reference numeral 604 denotes a RAM which has a data area for temporarily storing data necessary for processing such as user input data, internal variables, and search results, and stores various programs loaded from the auxiliary storage device 605. Has a program area. Reference numeral 605 denotes an auxiliary storage device that stores various programs, tables, and the like using a storage medium such as a floppy disk or a hard disk.
[0018]
<Local database system and local database>
The local database system (LDBS-n) 102 to 105 is a system for managing the local database (LDB-n) 106 to 109, interprets and executes a query sent via the computer network 117, and returns a processing result. To do. The local DB is a relational DB or the like, and the local DB system is a normal DB and a DB management system realized by an SQL server or the like.
[0019]
<Communication control device 110>
The communication control device 110 is a device that controls transmission and reception of signals between the heterogeneous DB integration system 101 and the computer network 117, and includes middleware that supports multitasking and multiuser.
[0020]
<Primitive interpretation device 111>
The primitive interpretation device 111 converts a script transmitted from the user terminal 118 via the computer network 117 and the communication control device 110 into a primitive and executes it. Here, the script is a so-called high-level language and is a process realized by a combination of primitives.
[0021]
FIG. 2 is a flowchart showing the flow of processing of the primitive interpretation device. A processing flow of the primitive interpretation device 111 will be described with reference to FIG.
[0022]
In step S201, one line of script is acquired.
[0023]
In step S202, the script is expanded into primitives based on the library 114, and the script arguments are reconfigured into the arguments of the primitives. Hereinafter, the number of primitives is K.
[0024]
The primitive mentioned here is realized as an object that includes an argument list arg, an internal variable called operation mode variable mode, and two methods called construction const () (called a constructor) and evaluation eval () (called an evaluator). Is. A primitive has no more than two arguments. The action mode variable takes two values, LAZY and EAGER, the constructor const () is a method that is executed when a primitive is declared, and the evaluator eval () is a method that evaluates the return value of the primitive. The evaluator executes selection, projection, join, etc., which are basic operations for database search.
[0025]
In step S203, J is set to 1. In step S204, the constructor of the Jth primitive is executed in the procedure described later with reference to FIG. As a result, the Jth primitive name is registered in the parameter table 115 together with the evaluation status and the address of the evaluation LDB.
[0026]
In step S205, J is updated to J + 1. In step S206, it is checked whether or not J exceeds K. If it exceeds, the process proceeds to step S207, and if not, the processes from step S204 to step S206 are repeated.
[0027]
In step S207, it is checked whether or not there remains a script to be converted, and if not, the process ends. If it remains, the processing from step S201 to step S207 is repeated.
[0028]
The processing flow of the constructor const () will be described with reference to FIG.
[0029]
In step S301, the message is stored in the argument list arg. The argument list is given as a sequence of primitive names to be evaluated when evaluating the primitives.
[0030]
In step S302, J is set to 1. In step S303, it is checked whether or not the J-th primitive name (hereinafter referred to as PRM _J ) is registered in the parameter table 115. If it is registered, the process proceeds to step S306.
[0031]
In step S304, the DB selection device 112 selects an LDB that can evaluate PRM _J , uses the LDB property table 116 to acquire the address of the selected LDB, and generates a PRM _J view in the LDB. Send. As a result, the argument is stored in the LDBS in the form of a view. In step S305, PRM _J is added to the parameter table, the evaluation status is set to “not yet”, and the acquired LDB address is set as the address of the LDB in charge of evaluation.
[0032]
In step S306, J is updated to J + 1. In step S307, it is checked whether J exceeds K. If it exceeds, the process proceeds to step S308, and if not, steps S303 to S307 are repeated.
[0033]
In step S308, it is checked whether or not the action mode variable is LAZY. If so, the process ends. If not, the process proceeds to step S309. In step S309, the evaluator eval () is executed.
[0034]
FIG. 4 is a flowchart showing a processing procedure of the evaluator eval (). The flow of processing of the evaluator X.eval () of the primitive X will be described with reference to FIG.
[0035]
In step S401, the evaluation status of X is acquired using the parameter table 115. In step S402, if the evaluation status of X is “not yet”, the process proceeds to step S404, and if “completed”, the process proceeds to step S403.
[0036]
In step S404, the LDB address in charge of evaluation of each primitive stored in the argument list is acquired.
[0037]
In step S405, if all the acquired LDB addresses for evaluation are the same as X, the process proceeds to step S406, and if not, the process proceeds to step S407.
[0038]
In step S406, since the LDB in charge of evaluating the arguments necessary for evaluating X is the same as X, it is not necessary to evaluate these arguments individually. This is because by directly evaluating X, the arguments stored in the view format in LDBS are automatically evaluated. Therefore, X is directly evaluated, the result is stored as the content of the pointer value, and the process proceeds to step S403.
[0039]
In step S407, J is set to 1. In step S408, the J-th primitive name PRM _J in the argument list is acquired. In step S409, PRM _J .eval () is executed. In step S410, the evaluation status is changed to “Done”.
[0040]
In step S411, J is updated to J + 1. In step S412, it is checked whether J exceeds K. If it exceeds, the process proceeds to step S412. If not, step S407 to step S412 are repeated.
[0041]
In step S413, the primitive is evaluated based on the argument value. For example, when there are two arguments, X (PRM ₁ , PRM ₂ ) is evaluated. Specifically, X (PRM ₁ , PRM ₂ ) is converted into the corresponding LDBS language and transmitted to the LDBS. At this time, the evaluator gives up the right to occupy the CPU when the inquiry information including the information of the target LDB and the information of the evaluator itself are transmitted to the communication control device 110, and the communication control device 110 receives such inquiry information. All the inquiries are made based on the above, and the system shifts to a reply waiting state from the LDB, and sends the answers to the evaluator based on the evaluator information in the order in which the answers are received. The evaluator stores the result received from the LDB as the content of the pointer value, and proceeds to step S403.
[0042]
In step S403, the contents indicated by the pointer value are stored in the return value of the primitive X, and the process ends.
[0043]
There are free variable primitives and user primitives as special classes of primitives. For free variable primitives, the action mode variable sets the received primitive name as its own function value value in LAZY and const (), and returns the function value value in eval (). Free variable primitives are generated, for example, for x in the user's script, for example “x = 12”.
[0044]
The user primitive action mode variable is EAGER. A partial query that gives the final result of the search query given by the user is expanded into user primitives. Therefore, a primitive string in which a user search query is expanded always includes one user primitive, and a given search query result can be obtained by evaluating the user primitive. On the other hand, evaluation of primitives that are not related to evaluation of user primitives is unnecessary for obtaining a search query result. Also, since the user primitive action mode variable is EAGER, the user primitive evaluator eval () is executed when the user primitive constructor const () is executed.
[0045]
<Database selection device 112>
The DB selection device 112 refers to the resource table 113 and returns a list of DBs including the primitive P arguments PRM1 and PRM2 as data. The resource table 113 stores the correspondence between the data name and a list of DB names including the data name.
[0046]
FIG. 5 is a flowchart showing the flow of search processing. Based on the components described above, the flow of search processing will be described with reference to FIG.
[0047]
First, in step S501, a search query is transmitted from the user terminal 118 to the heterogeneous database integration system 101.
[0048]
In step S502, the primitive interpretation device 111 expands the search query, which is a script, into primitives. In step S503, the constructor of each primitive is executed.
[0049]
In step S504, user primitives necessary for the search query result are evaluated, and in step S505, the result is transmitted to the user terminal.
[0050]
According to the present invention, a storage medium storing software program codes for realizing the functions of the above-described embodiments is supplied to an apparatus or system, and a computer in the apparatus or system reads out the program codes stored in the storage medium. It may be achieved by executing.
[0051]
Further, the computer in the apparatus or system reads out and executes the program code stored in the storage medium, thereby not only directly realizing the functions of the above-described embodiments but also on the computer based on the instruction of the program code. The case where the above-described functions are realized by processing of an OS or the like that is running on is also included.
[0052]
In these cases, the storage medium storing the program code constitutes the present invention.
[0053]
【The invention's effect】
As described above, according to the present invention, it is possible to avoid unnecessary procedures and data evaluation in order to obtain the final result requested by the user. As a result, communication traffic for evaluation can be reduced.
[0054]
Furthermore, the partial query for each database is stored as a view in the database, and a plurality of partial queries stored as these views are processed at once, so that the optimization function unique to the database can be fully utilized. .
[0055]
Furthermore, the execution of each primitive evaluation is controlled by the execution of each primitive evaluation, eliminating the need for the primitive interpreter to schedule primitives. This facilitates the design of the interpreter and reduces the program size.
[0056]
In addition, since the primitive has an operation mode variable, and based on the operation mode variable, it is determined whether to perform the evaluation of the primitive, so that it is possible to select lazy evaluation under application order evaluation. It becomes possible.
[0057]
Furthermore, when the inquiry information including the information of the database in charge of the evaluation and the information of the primitive that requested the inquiry are transmitted to the communication means, the exclusive right of the CPU is released, and all the information based on the inquiry information is released. Inquiries are made, the system shifts to a response waiting state from the database, and based on the information of the primitive, the responses are transmitted in the order received for evaluation of the primitive, so that inquiries to a plurality of databases are performed in parallel. Can be executed.
[Brief description of the drawings]
FIG. 1 is a functional configuration diagram of a heterogeneous database integration system according to an embodiment.
FIG. 2 is a flowchart showing a flow of processing of a primitive interpretation device.
FIG. 3 is a flowchart showing a process flow of a primitive constructor.
FIG. 4 is a flowchart showing a process flow of a primitive evaluator.
FIG. 5 is a flowchart showing a flow of search processing.
FIG. 6 is a block diagram showing a hardware configuration of a heterogeneous DB integration system.

Claims (15)

An information search apparatus that can use a plurality of databases,
Expansion means for expanding an input script-style search query into one or more primitives including user primitives;
A construction that selects a database in charge of evaluation for each developed primitive, and registers database information for evaluation that specifies the database and primitive information that specifies a further primitive to be evaluated for evaluation of the primitive. Means,
With reference to the evaluation person database information, evaluation means for evaluating each primitive using a database in charge of evaluation of the primitive;
Control means for referring to the primitive information and controlling the evaluation means to evaluate each primitive to be evaluated for evaluation of the user primitive;
And an output means for outputting the evaluation result of the user primitive as a result of the search query.   2. The information search apparatus according to claim 1, wherein the construction unit instructs the database selected for each primitive to generate and hold a view corresponding to the primitive. When the database in charge of evaluation of a primitive to be evaluated and the database in charge of evaluation of a further primitive to be evaluated for evaluation of the primitive are the same in the database in charge of evaluation, the control means includes: information retrieval apparatus according to claim 1, wherein the controller controls so as to suppress the evaluation of additional primitives.   2. The information retrieval apparatus according to claim 1, wherein the primitive has an operation mode variable, and the construction unit determines whether or not to perform the evaluation by the evaluation unit based on the operation mode variable. . Communication means for sending an inquiry to the plurality of databases and receiving an answer to the inquiry;
The evaluation unit releases the exclusive right of the CPU when the inquiry information including the information of the database in charge of the evaluation and the information of the primitive that requested the inquiry are transmitted to the communication unit,
The communication means makes all inquiries based on the inquiry information, shifts to a response waiting state from a database, and transmits responses in the order received for evaluation of the primitive based on the primitive information. The information search device according to claim 1. The evaluation means records in the evaluation status information that the evaluated primitive has been evaluated, refers to the evaluation status information prior to execution of the evaluation, and avoids evaluation of the evaluated primitive. The information search device according to claim 1. 2. The construction unit according to claim 1, wherein the construction unit checks whether or not the evaluation person database information for the primitive that is the current processing target has been registered, and avoids re-registration when the information has been registered. Information retrieval device. An information search method in an information search apparatus comprising a deployment means, a construction means, an evaluation means, a control means, and an output means, and is capable of using a plurality of databases ,
The expanding means expands the input script-type search query into one or more primitives including user primitives;
The construction means selects a database in charge of evaluation for each developed primitive, database information for evaluation for specifying the database, and primitive information for specifying a further primitive to be evaluated for evaluation of the primitive. And a construction process for registering
The evaluation means refers to the evaluation database information, and evaluates each primitive using a database in charge of evaluation of the primitive; and
A control step in which the control means controls the evaluation means to evaluate each primitive to be evaluated for evaluation of the user primitive with reference to the primitive information ;
An information search method comprising: an output step in which the output means outputs an evaluation result of the user primitive as a result of the search query. 9. The information search method according to claim 8 , wherein the construction means instructs the database selected for each primitive to generate and hold a view corresponding to the primitive in the construction step. . When the database in charge of evaluation of the primitive to be evaluated and the database in charge of evaluation of a further primitive to be evaluated for evaluation of the primitive are the same in the database information in charge of evaluation, in the control step, The information search method according to claim 8 , wherein the control unit performs control so as to suppress evaluation of further primitives. 9. The primitive according to claim 8 , wherein the primitive has an operation mode variable, and based on the operation mode variable, in the construction step, the construction unit determines whether to perform an evaluation by the evaluation unit. Information retrieval method described. In the evaluation step, the evaluation means releases the exclusive right of the CPU at the time when the inquiry information including the information of the database in charge of the evaluation and the information of the primitive that requested the inquiry are transmitted to the communication unit,
The communication unit makes all inquiries to the database based on the inquiry information, transitions to a response waiting state from the database, and receives an answer to the inquiry. 9. The information search method according to claim 8 , wherein the responses are transmitted in the order received for evaluation. The evaluation means records in the evaluation status information that the primitive that has been evaluated in the evaluation step has been evaluated, refers to the evaluation status information prior to the execution of the evaluation, and evaluates the evaluated primitive. The information search method according to claim 8 , wherein the information search method is avoided. The construction means, in the construction step, checks whether or not the evaluation person database information for the primitive that is the current processing target has been registered, and if it has been registered, avoids re-registration. Item 9. The information search method according to Item 8 . On the computer,
Expanding a scripted search query into one or more primitives including user primitives;
A construction that selects a database in charge of evaluation for each developed primitive, and registers database information for evaluation that specifies the database and primitive information that specifies a further primitive to be evaluated for evaluation of the primitive. Process,
An evaluation step of evaluating each primitive using a database in charge of evaluation of the primitive with reference to the evaluation person database information;
A control step of referring to the primitive information and controlling the evaluation means to evaluate each of the primitives to be evaluated for the evaluation of the user primitive;
A computer-readable storage medium storing an information search program, wherein an output step of outputting the evaluation result of the user primitive as a result of the search query is executed .

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