JPS6373328A - Processor for retrieving data content - Google Patents

Abstract

PURPOSE:To correctly decide a retrieval conditional equation by encoding the decided result of a unit conditional equation with two bits and comparing it with combination in which a composite conditional equation registered in an associated memory is realized. CONSTITUTION:Three values of 'realized', 'not realized', and 'indefinite' that are the decided results of the unit conditional equation of a unit conditional equation deciding part 4, are encoded with two bits. Next, a pair of the decided results of the unit conditional equation in which a given composite conditional equation is realized, are registered in an associated memory CAM13 provided in advance in a composite conditional equation deciding part 5. And after the retrieval processing of a content is started, the coincidence retrieval of the CAM13 is performed at every record by the pair of the decided results of each unit conditional equation, and the realization of the composite conditional equa tion is decided by the existence of a coincided entry. In this way, it is possible to correctly decide the retrieval conditional equation.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is capable of searching only a group of records having contents that match a given search condition expression from among a huge group of records stored in a secondary storage device, etc. The present invention relates to a data content search processing device that selects and outputs data, and particularly relates to a method of configuring a search condition expression determination unit.

[Conventional technology]

Figure 1 shows an example of the configuration of a data content search processing device that selects and outputs only a record group whose content matches a specified detection condition expression from a huge group of records stored in a secondary storage device, etc. show. In FIG. 1, 1 is a secondary storage device for storing record groups, 2 is a data content search processing device, and 9 is a main device. The data content search processing device 2 includes a secondary storage control unit 3 that controls reading and writing of data in the secondary storage device 1, and determines whether a unit conditional expression given for each field of the read record group holds true or not. a unit conditional expression determination unit 4 that uses the determination result of the unit conditional expression to determine whether a given compound conditional expression holds true or not; a compound conditional expression determination unit 5 that temporarily stores the read record; A record buffer section 6 that selects and temporarily stores only the record group for which the conditional expression is satisfied, an I10 interface control section 7 that transfers the record group selected by the record buffer section 6 to the main unit 9, and overall control and search of these. It is composed of a common control section 8 that performs preparation processing.

FIG. 2 shows an example of the structure of records targeted by the data content search processing device 2, where the records are Fl, F2, .
F3. An example is shown in which the field consists of five fields, F4 and F5. Table 1 shows an example of the search condition expression for the record to be searched.

Unit conditional expression 1 (UCI) and unit conditional expression 2 (UCI) for one example of
2) and unit conditional expression 3 (UC3), respectively, field Fl is equal to constant C, field F2 is greater than field F3, and field F4 is constant C
The condition is specified that the number is 2 or less. Complex conditional expression (
G) specifies that the search condition expression is satisfied when both UCI and UC2 are satisfied, or when UCl is not true and UC3 is true.

The data content search processing device 2 in FIG. 1 determines whether the search condition expression shown in Table 1 holds true for a group of records having the format shown in FIG. 2, and selects only the records that hold. Select and output.

That is, the unit conditional expressions UCI, UC2, and UC3 are sequentially determined by the unit conditional expression determination section 4, and the composite conditional expression G is determined by the composite conditional expression determination section 5 using the determination results.

Here, if the field targeted by the unit conditional expression has a specific value, in the unit conditional expression determination 4, it is determined whether it is true (T) or not true (F) as described above. On the other hand, if the field does not have a specific value (in this case, the field is said to be a "blank value (null) j"), it is impossible to determine whether the unit conditional expression holds true or not, so it is ''(M), but conventionally, the determination result is T.

In order to avoid increasing the circuit scale when the three values of F and M are used, F is used even when the value is undefined. That is, in the conventional device, the output of the unit conditional expression determining section 4 was two values, T and F. Then, in the compound conditional expression determination section 5, T is the output of the unit conditional expression determination section 4.

Regarding the binary values of F, AN according to the given compound conditional expression
Logical operations of D, OR, and NOT are executed, and if the final result is true ('T), it is determined to be an output record.

[Problem that the invention seeks to solve]

In the above-mentioned conventional technology, a logical contradiction may occur in which the complex conditional expression is determined to be true and is set as an output tuple, even though the result of the judgment on the complex conditional expression is originally undefined and does not become an output tuple. That is, in the compound conditional expression, the UCI of the example in Table 1
If the target field of the unit conditional expression to which NOT is added is a blank value, as in Since M is reported to the complex conditional expression determination unit as F, it becomes T due to NOT. For this reason, Table 1
In the example, if UC2 is F and UC3 is T, the compound conditional expression is originally M, but NOT
UCI becomes T, and the complex conditional expression is determined to be T by AND with UC3.

To avoid this, it is necessary to disallow blank values as field values or to not use NOT in complex conditional expressions, and only very limited data content search processing is possible.

An object of the present invention is to output three values of T, F, and M as the output of the unit conditional expression determination section in order to avoid the above-mentioned usage restrictions, and to output three values for the three values of T, F, and M in the compound conditional expression determination section. It is an object of the present invention to provide a data content retrieval processing device that uses a three-value logic decision construction method and has a small circuit scale that enables operations equivalent to logical AND, OR, and NOT operations.

[Means and effects for solving the problem] The present invention provides unit conditional expression determination results that are “held”, “not held”, and “indeterminate”.
The 3 values of are encoded in 2 bits, and a set of unit conditional expression judgment results for which the given compound conditional expression is satisfied is registered in advance in the associative memory, and after the start of content search processing, it is stored for each record. The associative memory is searched for a match based on the set of determination results of each unit conditional expression, and based on the existence of a matching entry, it is determined whether the compound conditional expression is satisfied.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In the embodiment of the present invention, the overall configuration of the data content search processing device is as shown in FIG.

In the case of the present invention, the unit conditional expression determining unit 4 determines whether the unit conditional expression given for each field of the search target record group is true (T), not true (F), or indefinite (M), and The three values of expression judgment results, ie, established, not established, and indefinite, are divided into 2.
Encode and output in bits. Figure 3 shows an example of this encoding, where the code “OO” II is expressed in 2 bits.
OI II.

"10 '"(#l l out of 11, "o
o ''' is undefined (M), "01''' is not true (F),
l(1011 indicates that it is true (T), and '11' indicates that it is not used.

FIG. 4 is a block diagram of an embodiment of the complex conditional expression determining section 5 in the present invention, in which the maximum allowable number of unit conditional expressions is four. In FIG. 4, 10 is a signal line that transfers the determination result of the unit conditional expression, 11 is a group of result latches 7 that stores the unit conditional expression determination result (8 bits) propagated by the signal line 10, and 12 is a group of result latches. Contents of 11 are stored in associative memory (CA).
13 is a content addressable memory (CAM); 14 is a CAM 13;
21 is an area for storing a bit indicating whether the entry in the CAM 13 is valid; 22 is a unit conditional expression judgment necessary for the compound conditional expression to hold true; An area for storing the resultant combination pattern, 111 is a latch that always holds "1" to match the valid entry display It 1 )l in order to match only with valid entries, 112 is a latch for storing the judgment result of the unit conditional expression (each 2 bits).

Figure 5 assumes that the unit conditional expression judgment results as shown in Figure 3 are encoded, and when the search conditional expressions shown in Table 1 are given,
This shows the contents to be registered in AM13. In FIG. 5, 221, 222, and 223 are columns in which the determination results of the unit conditional expressions UCI, UC2, and UC3 are registered, respectively. 224 is an unused column. 231,232
are the two product terms (tJcl A
NI) UC2), (NOT UCI AND UC3)
) are registered respectively. 233 is an unused entry group. 23 represents a masking function of the CAM 13 that allows the corresponding bit to match any of 0°1. That is, in entry 231, column 221
, 222, and 223 are "10", '10', and 'Kasakushi', respectively, which indicates that when UCl and UC2 are true, G is true no matter what UC3 is. In addition, in entry 232, UCI is similarly not established,
When UC3 is true, G is true regardless of which UC2 is. Therefore, it indicates that G is established when it matches either entry 231 or entry 232.

Next, the operations shown in FIGS. 1 and 4 will be explained.

First, prior to data content search processing, a preparatory operation is performed in accordance with a given search condition expression under the control of the common control unit 8. In this preparatory operation, first, a result latch group 11 and a column of the CAM 13 are assigned to each unit conditional expression.

Next, an entry in the CAM 13 is assigned to the product term in the compound conditional expression.

Next, for each entry in CAM13, for the unit conditional expression that exists in the product term, the corresponding column is set to ``II 10 II'', and for the unit conditional expression with NOT, the corresponding column is set to ``0''.
1”, and for unit conditional expressions that do not exist, set 1 to the corresponding column.
``Senshin'' (mask).

All unused entries and columns are set to 11''. The preparation operation is now complete, and data content search processing can now be performed.

After starting the data content search process, the secondary storage device control unit 3 reads out a group of records to be searched from the secondary storage device 1 and temporarily stores them in the record buffer unit 6. For each record, all unit conditional expressions are judged in the unit conditional expression judgment section 4, and the result is set in the result latch group 11 in the compound conditional expression judgment section 5 via the signal line 10. When the all-results latch is set, a match search is performed on the CAM 13 via the search signal line 12. Note that the unused bits in the result latch group 11 are fixed at tt 11 u. If an entry exists in the CAM 13 as a result of the matching search, it means that the compound conditional expression is satisfied. On the other hand, if the - entry does not exist, this means that the complex conditional expression is not true, that is, it is not true or is undefined. A record with a matching entry matches the search condition expression, is determined to be an output record, and is held in the record buffer unit 6. On the other hand, if there is no matching entry, the record is discarded from the record buffer unit 6. Every time the search condition matching records held in the record buffer unit 6 reach a certain capacity, they are transferred to the main unit 9 via the I10 interface control unit 7.

Here, in the example of Table 1, the determination results will be examined with reference to FIG. 5 in the case where UCI, UC2, and UC3, which were explained as causing logical contradiction in the prior art, are indefinite, not established, and established, respectively. In this case, the corresponding bit of the result latch is “00”.

Since "01" and "10" are set and do not match any entry in the CAM, the search condition expression is not satisfied and no logical contradiction occurs.

In this way, in this embodiment, the judgment result of the unit conditional expression is encoded in 2 bits, and the judgment is made by registering in the CAM all the combinations of the unit conditional expression judgment results that make the compound conditional expression hold. Even if the necessary usage restrictions are not set, logical contradictions will not occur in the determination of search condition expressions. Moreover, the complex conditional expression determination section of this embodiment is composed only of a CAM and its peripheral circuits, and the circuit scale is small.

In addition, in the description of the above embodiment, the maximum allowable number of unit conditional expressions is set to 4, but the present invention is not limited to this.

Furthermore, the configuration of the CAM itself does not matter whether it uses an associative memory integrated circuit or whether an equivalent circuit is configured by the logic circuit 1.

〔Effect of the invention〕

As explained above, in the present invention, the determination result of a unit conditional expression (established, not established, indeterminate) is encoded and compared with combinations registered in the CAM that result in the establishment of the complex conditional expression. Since the search condition expression is evaluated as equivalent to the search condition expression, there is no need to set restrictions such as not using NOT in the compound condition expression or not allowing blank values as target data, as in the past. It is possible to determine. Furthermore, since the complex conditional expression determination section is comprised only of an associative memory and its peripheral circuits, it has the advantage of having a small circuit scale and fast determination speed.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an embodiment of the data content search processing device of the present invention, FIG. 2 is a diagram showing an example of the configuration of records targeted for data content search processing, and FIG. 3 is a unit condition in the present invention. FIG. 4 is a diagram showing an example of the configuration of the complex conditional expression determination section in the present invention, and FIG. 5 is a diagram showing an example of the contents of the CAM in FIG. 4. DESCRIPTION OF SYMBOLS 1... Secondary storage device, 2... Data content search device, 3... Secondary storage device control unit, 4... Unit conditional expression determination unit, 5... Complex conditional expression determination unit, 6 ...Record 1-'/< buffer section, 7.I10 interface control section, 8.Common control section, 9.Main device, 10.Unit conditional expression judgment result signal, 1], ...Unit conditional expression judgment result latch, 12...C
AM match search signal line, 13...CAM, 14...
CAM matching entry existence signal line. Procedural amendment (method) December 2, 1985 2, Name of the invention Data content search processing device 3, Person making the amendment Relationship to the case Applicant address 1-1-6 Uchisaiwai-cho, Chiyoda-ku, Tokyo Name
(422) Representative of Nippon Telegraph and Telephone Corporation
Tsune Shinfuji 4, Agent 5, Date of amendment order: November 5, 1985 (Shipping date: November 5, 1986)
6. Number of inventions increased by amendment None 8. Contents of the amendment Amend "No. 5" on page 14, line 15 of the specification cylinder to "Fig. 5."that's all

Claims (1)

[Claims] (1) A search condition that targets a large group of records consisting of multiple fields and consists of a unit conditional expression that specifies a search condition for any field or multiple fields, and a complex conditional expression that is a logical expression that uses the unit conditional expression as an element. In a data content search processing device that is given an expression and selects and outputs only a group of records for which the search conditional expression holds true, the three-value states of “true,” “not true,” and “indeterminate” that are the judgment results of the unit conditional expression are It is also equipped with a group of result latches that hold the coded unit conditional expression judgment results, and an associative memory that can perform a match search using the group of result latches as keys, and performs data content search processing. As a preparatory operation, based on the given compound condition, all the combinations of contents of the resultant latch group that make the compound conditional expression hold are registered in the associative memory, and after the data content search process starts, multiple When the unit conditional expression is judged and the judgment results are all in the result latch group, a match search is performed on the associative memory using the contents of the result latch group as a key, and the establishment of the compound conditional expression is determined by determining the existence of a matching entry. A data content search processing device characterized by determining an output record.