JPS59188765A - Processing device of data base inquiry - Google Patents

Abstract

PURPOSE:To decrease the processing time by providing an address holding condition so as to utilize the result of indexing access in the processing of the preceding inquiry when the inquiry executed immediately thereafter includes the same retrieval condition as the preceding inquiry. CONSTITUTION:Whether or not there exists a coincidence in the object table phrase and the condition phrase between an inputted inquiry Qn and an inquiry Qm just before is inquired and the result is analyzed by an analyzing means 2. When there exists a coincident phrase, it is transmitted to the address holding means 1 and the set of corresponding record addresses is given to a set operating means. Further, the address holding means receives the address set of the record to the inquiry Qn from an index access means 3 and stored. The set operating means 4 forms the address set between the address holding means 1 and the index access means 3 based on a signal line 24, transmits the result to a record access means 5 and extracts the corresponding record from a data base file 6.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a data processing apparatus, and more particularly to an arrangement processing apparatus for relational databases.

A relational database is assumed to consist of a set of tables, and the columns that make up the tables are called columns, and the rows are called records. Each record is a set of column values that make up the table. It is assumed that each table is given a table name, and each column is given a column name. It is assumed that indexes are provided for all columns subject to search conditions. However, it is assumed that the index is a correspondence table between the key value of a certain column in the table and the address in the database file of the record having that key value as the column value. An instruction command for conditionally searching records included in a table of a relational database is called a match. A makeshift statement generally specifies a target table clause to specify the table to be searched, a condition clause to specify the search condition for records in the table as a condition regarding column values, and the column name of the column to be retrieved as a result. It consists of a purpose column clause.

As a makeshift sentence format, 5EQUEL by Chamberlin, D., D. and Boyce, RoF:
A S structured English Quer
y Language” paper (Proc, ACMS
IGFIDET workshop, May 19
74. pp. 249-264) as proposed below.

Arrangement name: 5ELBCT Purpose column phrase FB, O
M Target table phrase WHERE Conditional phrase An example of a query for searching a table using the above-mentioned makeshift sentence format is shown below.

Q: 5EIJCT COLt FROM TBL WHERE C0L2210 AND C0L3>20 Q is the inquiry name. The value of the conditional clause of makeshift sentence Q1 is C
0L2=10ANDCOL3>20, the value of the target table clause is TBL, the value of the target column clause is C0LI, and the interval Q is the records included in the table TBL.
The value of column C0L2 is equal to 10 and column C0L3
This command instructs to select records whose value is greater than 20 and to extract the value of column C0L1 of the selected record. It is assumed that the search conditions included in the conditional phrase are connected by an AND combination.

FIG. 1 is an explanatory diagram showing how to use the ζ database file and index. The database file contains records of table TBL, tI+b+13
are the first. Second. It shows the address of the third record. Also, COL 1.

C0L2. C0L3 is a column placed on the table.

IDXI and IDX2 are each column C0LI.

It is assumed that the index for C0L3 is shown and both are stored in index storage. Further, the address storage stores a record address set obtained as a result of index access.

As shown in the figure, it is assumed that records are stored in a database file and an index has been created for these records. The proposed method will be explained by taking the timing Q as an example. First, using the index for column C0L2, address set Alt1) of records with key value 10) = (t
Find r ). At the same time, a set AI(2)=('1*t2) of record addresses with key values greater than 20 is obtained using the index for column C0L31. Then, the set product B1 of the set A1(1) and the set As(2) is determined. The resulting set product B,=(t,) is the interval Q,
This is a set of record addresses of records that satisfy the search conditions.

Furthermore, after executing the search for the timing Q, the timing Q shown below is obtained.
Consider performing the second search.

Q: 5ETJECT C0L2F OM T
BL WHlg coh1=s AND C0L3>20 In the conventional method, the adjustment Q2 was executed independently of the adjustment Q.

That is, using the index for column C0L1, the first
A2(1)” = (it, t
3) and using the index for column C0L3, record address set A2(2) = (t
+, ``t''. Then, the set product B2 ''(``t'') of record address set 4(1) and A2(2) is calculated.
seek.

By the way, the second search condition C0L3>20 for the timing Q2
is equal to the second search condition for the timing Ql.

Therefore, if there is no update to the Chiful TBL in the database between the execution of the adjustment Ql and the execution of the adjustment Q2, the address set AI (21 and A2 (2)
is equivalent. In this case, the conventional method had the disadvantage that the same index access processing had to be repeated at the timings Q and Q2, requiring wasted processing time.

An object of the present invention is to save a set of record addresses of records that satisfy search conditions obtained at the time of execution of reconciliation;
By using the saved record address set when the same search conditions are specified later at another time,
It is an object of the present invention to provide a database alignment processing device that solves the drawbacks of the above-mentioned conventional methods.

Next, the configuration and operation of the present invention will be explained while showing one embodiment of the present invention.

FIG. 2 shows a block diagram of an embodiment using the present invention, in which address holding means 1, alignment analysis means 2, index access means 3, set operation means 4, record access means 5,
It is composed of a database file 6 and an index storage 7.

Here, we will explain the operation during the execution of maize (Minoru.). However, immediately before maisekiogyo (komaai Q, . . .).

It is assumed that the Database file 6
It is assumed that records of a table are stored in , and index storage 7 stores indexes for columns of the table.

First, at the start of the calculation, the address holding means 1 contains the search condition cm(
j), jm1.・・・r Record address assembly of records that satisfy each of Km's length hmCj), jm1゜・
. . p Km is stored, and it is assumed that the adjustment analysis means 2 stores the target table phrase Ill m and the conditional phrase CCm of the adjustment Q, . It is assumed that a makeshift sentence QI is input via the signal line 21. When the makeshift analysis means 2 receives the makeshift sentence Q0,
First, the target table phrase Tfl of the make-up sentence and the make-up Q, n
The target table phrase T. If Tゎ=Tm, then the conditional phrase CCn of the makeshift sentence Qn and the conditional phrase CCn of the makeshift sentence Qfl are checked. (= Adjust (j) Qi
When the third search condition of the conditional phrase CCi is,
A set Jff of jm in which jn exists such as Cn (Jn) == Cm (Jm) and a corresponding set J of jn are determined, and Jm is sent to the address holding means 1 via the signal line 22. After checking the makeshift sentence Q, the makeshift analysis means 2 sends a signal S to the set calculation means 4 via the signal line 24, and sends the search condition (C, (j) l j '−Jn) is sent.

However, the signal S has a value of 1 when Jn is not empty, and a value of O when Jn is empty. Also, (C,,U)
It is assumed that l jfEJ, ) indicates a search condition number j that is not included in J, among the search conditions for timing Q. Furthermore, the arrangement analysis means 2 sends the object column phrase Mn of the arrangement sentence Q□ to the record access means 5 via the signal line 25.

In the address holding means 1, a set of search condition numbers J,...
, record address set (A, , (j month j6J
□) is taken out and sent to the set calculation means 4 via the signal line 11.

In the index access means 3, regarding the search condition (C, (j) l f"J, ) sent from the alignment analysis means 2, the signal line is sent from the index memory 7 provided in the column targeted by the condition. 33, and search conditions (C,
The address set (An(J) l j6J, ) of records satisfying (j) l jeJn) is determined and sent to the set calculation means 5 via the signal line 31, and also sent to the address holding means 1 via the signal line 32.

In the address holding means 1, the address set (A, , (j)
1j J, ) is received, it is converted into (A-(j) l j
eJm).

The set calculation means 4 receives the signal S on the signal line 24,
When the value of S is 1, the address set (Am(J)lJ(Jm) sent from the address holding means J and the address set (An(i)l
]6Jn) Find the set product Bn for . In this case, any record address included in the address set Bnl is an element of all address sets (A, n(j) l j6 Jm) and (A, (j) l jeJl+). be. On the other hand, the value of S is 0
, then the address set (A, , (j) l j
tEJ, , ) is obtained, and this is set as address set B0.

After completing the calculation, the set calculation means 4 sends the address set to the record access means 5 via the signal line 41.

When the record access means 5 receives the address set Bn on the signal line 41 and the target column phrase Mn from the signal line 25, it receives the address set B. The record indicated by is retrieved from the database file 6 via the signal line 33, and the value of the column specified by the target column phrase M0 is output via the signal line 51. A computation end timing signal t1 is sent to 2.

In the timing analysis means 2, the signal 1. Once received, the next inquiry can be accepted.

The above is the operation of one embodiment of the database alignment processing device of the present invention.

As described above, according to the present invention, by providing the address holding means, when the second query executed immediately after the first query includes the same search condition as the first query, the first query is The index access results in the process are used as they are in the second query process. As a result, it has the effect of eliminating wasteful index access processing and shortening processing time.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining how to use database files and indexes, and FIG. 2 is a block diagram showing one embodiment of the present invention. In the figure, 1... address holding means, 2... timing analysis means, 3... index access means, 4... set calculation means, 5... record access means, 6... cheetah base File, 7...indicates index storage, respectively. 11; Rito Yu 53. ko2. E, j de 11. silkworm
Susumu (, 39 Figure 1 IDXI 11) X3 address responsibility B+ - (t,)
82 = (t2) Figure 2

Claims (1)

[Claims] In a database search system that maintains a relational database consisting of a set of tables in which columns are columns and rows are records, an index is provided for all columns that are subject to search conditions, and a condition search for the table is performed via the index, A makeshift analysis means that analyzes a makeshift sentence, an index access means that accesses the index and obtains the address in the database file of a record that satisfies the query search condition, and an address holding means that holds a record address set that is the index access result. , a set operation means for obtaining a set score between record address sets, and a record access means for retrieving information on records indicated by the record address set from a database file, and in executing two consecutive queries, the first query When executing the first query, a set of addresses of records that satisfy the search conditions of the first query is stored in the address holding means, and when the second query is executed, the second query is checked by the timing analysis means, and the first If the same search condition as the search condition of the query is specified in the second match, the record address set 1 prohibited by the address holding means is retrieved as the index access result for the search condition 1. ,
The index access means obtains a record address set 2 that satisfies the remaining search conditions 2 of the second query via the index, and the set calculation means obtains the record address set 1 and the record address set 2 as a set result. A database alignment processing device characterized in that a record address set 3 is obtained, and the record access means extracts information of the record indicated by the record address set 3 from a database file as a database search result for a second alignment.