Title: Data processing method using record division storing scheme and apparatus therefor
Abstract: A record having a fixed length data portion and a variable length data portion is stored in memory units, each capable of being inputted/outputted independently, in unit of sub-record while the fixed length data portion is divided into a plurality of fixed length sub-records each having the same length and the variable length data portion is made one variable length sub-record. When data operation of the record such as retrieval, update and deletion is required, sub-records necessary for the data operation are limited and the data operation is made in a unit of one or more sub-records, so that data processing of unnecessary sub-records is not made.
Patent Number: 6,954,759 Issued on 10/11/2005 to Yamaguchi
| Inventors:
|
Yamaguchi; Kota (Yamato, JP)
|
| Assignee:
|
Hitachi, Ltd. (Tokyo, JP);
Hitachi Software Engineering Co., Ltd. (Yokohama, JP)
|
| Appl. No.:
|
796562 |
| Filed:
|
March 2, 2001 |
Foreign Application Priority Data
| Jul 09, 1992[JP] | 04-181950 |
| Current U.S. Class: |
707/102; 707/1; 707/100; 711/114 |
| Intern'l Class: |
G06F 017/30; G06F 007/00; G06F 017/00; G06F 012/00; G06F 012/14 |
| Field of Search: |
707/1,100,102
711/114
|
References Cited [Referenced By]
U.S. Patent Documents
| 3931612 | Jan., 1976 | Stevens et al.
| |
| 4092732 | May., 1978 | Ouchi.
| |
| 4575798 | Mar., 1986 | Lindstrom et al.
| |
| 4780808 | Oct., 1988 | Moreno et al.
| |
| 5175852 | Dec., 1992 | Johnson et al.
| |
| 5257362 | Oct., 1993 | Menon.
| |
| 5263145 | Nov., 1993 | Brady et al.
| |
| 5586292 | Dec., 1996 | Yamaguchi.
| |
| 5943683 | Aug., 1999 | Yamaguchi.
| |
| Foreign Patent Documents |
| 01-106217 | Apr., 1989 | JP.
| |
| 02-52305 | Feb., 1990 | JP.
| |
Other References
James Bradley, "File and Data Base Techniques," 1981 by CBS College Publishing,
pp. 53-58.
|
Primary Examiner: Coby; Frantz
Assistant Examiner: Nguyen; Cindy
Attorney, Agent or Firm: Mattingly, Stanger, Malur & Brundidge, P.C.
Parent Case Text
This is a continuation application of U.S. Ser No. 09/324,731, filed Jun. 3,
1999 U.S. Pat. No. 6,216,203, which is a continuation application of U.S. Ser.
No. 08/767,188, filed Dec. 17, 1996, now U.S. Pat. No. 5,943,683, which is a continuation
application of U.S. Ser. No. 08/087,162, filed Jul. 2, 1993, now U.S. Pat. No. 5,586,292.
Claims
1. A data processing method in which a plurality of records, each including at
least a plurality of fixed length data portions are divided and stored in a plurality
of storage units, comprising:
dividing said fixed length data portion of each of said records into a plurality
of fixed length sub-records having respective logical names;
storing said fixed length sub-records in a plurality of storage units such that
said fixed length sub-records having a same logical name are stored in a same one
of said storage units;
managing a storage situation of said storage units as file definition information
collectively;
performing data processing of said record in a unit of sub-record with reference
to said file definition information; and
inputting a query,
wherein, if one logical name is specified in the query, said fixed length sub-records
having the specified logical name are read from the same storage unit.
2. A data processing method according to claim 1, wherein said step of performing
includes the steps of:
determining at least one sub-record based on the query;
reading the at least one determined sub-record in a record from one of the storage
units;
checking whether the at least one read sub-record meets the query; and
if the at least one read sub-record meets the query, reading other sub-records
in the record from other of the storage units.
3. A data processing method in which a plurality of records, each including at
least a plurality of fixed length data portions are divided and stored in a plurality
of storage units comprising:
dividing said fixed length data portion of each of said records into a plurality
of fixed length sub records having respective logical names;
storing said fixed length sub-records in a plurality of storage units such that
said fixed length sub-records having a same logical name are stored in a same one
of said storage units;
generating file definition information which correlates the sub records to the
storage units;
accessing one of said sub-records with reference to said file definition information;
and
performing data processing in accordance with the one sub-record; and
inputting a query,
wherein, if one logical name is specified in the query, said fixed length sub-records
having the specified logical name are read from the same storage unit.
4. A data processing method according to claim 3, wherein said fixed length sub-records
are stored in locations having the same physical address of said plurality of storage units.
5. A data processing method according to claim 3, wherein data processing of
said record includes retrieval, update, addition, and deletion.
6. The data processing method of claim 3, wherein said fixed length sub-records
are stored in the storage units at identical addresses thereof.
7. The data processing method according to claim 3, wherein said fixed length
sub-records are stored in identical physical locations within respective ones of
the storage units.
8. A data processing system in which a plurality of records, each including at
least a plurality fixed length data portions are divided and stored in a plurality
of storage units, comprising:
means for dividing said fixed length data portion of each of said records into
a plurality of fixed length sub-records having respective logical names;
means for storing said fixed length sub-records in a plurality of storage units
such that said fixed length sub-records records having a same logical name are
stored in a same one of said storage units;
means for managing a storage situation of said storage units as file definition
information collectively;
means for performing data processing of said record in a unit of sub-record with
reference to said file definition information; and
means for inputting a query
wherein, if one logical name is specified in the query, said fixed length sub-records
having the specified logical name are read from the same storage unit.
9. A data processing system according to claim 8, wherein said performing means includes:
means for determining at least one sub-record based on the query;
means for reading the at least one determined sub-record in a record from one
of the storage units;
means for checking whether the at least one read sub-record meets the query;
and
if the at least one read sub-record meets the query, reading other sub-records
in the record from other storage units with said means for reading.
10. A data processing system in which a plurality of records, each including
at least a plurality of fixed length data portions are divided and stored in a
plurality of storage units comprising:
means for dividing said fixed length data portion of each of said records into
a plurality of fixed length sub records;
means for storing said fixed length sub-records in a plurality of storage units
such that said fixed length sub-records having a same logical name are stored in
a same one of said storage units;
means for generating file definition information which correlates the sub records
to the storage units;
means for accessing one of said sub-records with reference to said file definition
information; and
means for performing data processing in accordance with the one sub-record; and
means for inputting a query,
wherein, if one logical name is specified in the qeury, said fixed length sub-records
having the specified logical name are read from the same storage unit.
11. A data processing method according to claim 10, wherein said means for storing
stores said fixed length sub-records are stored in locations having the same physical
address of said plurality of storage units.
12. A data processing method according to claim 10, wherein data processing system
of said record includes means for retrieval, update, addition, and deletion.
13. The data processing method of claim 10, wherein said means for storing stores
said fixed length sub-records in the storage units at identical addresses thereof.
14. The data processing method according to claim 10, wherein said means for
storing stores said fixed length sub-records in identical physical locations within
respective storage units.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a file management system having a large capacity
memory for storing long data, and more particularly to a data processing method
and an apparatus therefor in a system for managing a multimedia data base, a map
information data base and a knowledge data base in which character texts, figures
and image data are stored.
In the system which handles long data such as character texts, figures and image
data, since a logical record length of data is increased and an amount of data
to be transferred between an input/output buffer set in a main memory in a central
processing unit for processing sing data and an external memory unit for storing
data is increased, a sufficient access performance is not obtained due to a limitation
of a data transfer rate. Further, by repeating update, addition and deletion of
expanded records, invalid areas are scatteringly formed in a file to thereby deteriorate
a space efficiency of the file.
In this connection, JP-A-1-106217 discloses a technique that long data is divided
and the divided data are stored in a plurality of secondary memory units in parallel.
In this technique, the long data is divided to form divided files and information
relative to memory locations of the divided files in the secondary memory units
is stored in one of the divided files. When the long data is read out, the information
relative to the memory location is read out from one of the divided files and the
divided files in the secondary memory units indicated by the information are read
out in parallel to restore the long data. When the data is updated, the restored
data is updated and the updated data is divided again to store in the secondary
memory units.
Further, JP-A-2-52305 discloses a partially updating method of image data
in which in an image file apparatus for storing a document such as a drawing as
an image file, an inputted document is divided into a predetermined number of divided
image units to be stored and when any modification occurs in the document, only
a divided image unit having contents which are to be modified is modified and stored
again. In this technique, when the modification occurs, the whole image is not
stored again and accordingly the image file can be updated at high speed.
SUMMARY OF THE INVENTION
The inventors have found the following problems as a result of studying the techniques
in the prior arts.
In the former prior art technique, since data processing for all of the divided
files is made in parallel, there is a problem in a speed of operation for processing
only data of a portion of the divided files independently.
Further, the management of the input/output buffers and the improvement
of operation speed thereof are not considered sufficiently. More particularly,
the system must provide a large number of input/output buffers in the main memory
in order to transfer data in parallel effectively. Since a record length of the
multimedia data such as character texts, figures, images or the like is several
hundred KB to several hundred MB, a main memory capacity required for input and
output of one record is increased. Accordingly, when all of requests for record
operation are made in unit of record, multi-processing of a plurality of requests
for record operation is restricted by the main memory capacity and a time loss
occurs due to waiting for an unoccupied input/output buffer, so that the throughput
of the whole system is reduced.
In addition, in a retrieval instruction of record, only a partial item of data
is used to make judgment of a retrieval condition which is made by reading data
into the input/output buffer in the main memory, although all of data constituting
the record is read in the buffer and accordingly useless reading of data having
no relation to the retrieval condition is made in the case where the condition
is not matched to thereby occupy the input/output buffer uselessly.
In the latter prior art technique, since only the image unit modified actually
of the divided image units is recognized and stored again, input and comparison
of correction data and unmodified data are necessary, so that useless input of
image units having data not updated and useless occupation of the input/output
buffer occur similarly.
Furthermore, in both of the prior art techniques, data to be handled
is intended to be fixed length data, while handling of variable length data is
not described. When the variable length data is divided simply in the same manner
as in the prior art, there is the following problem.
When a length of divided sub-records is changed, the capacity of each of the
divided files is varied and storage addresses such as physical addresses or relative
byte addresses in a file storing the sub-records are also varied for each of the
divided files. Accordingly, if the relation between the sub-records constituting
one record is not established by holding a storage address of an actual value of
a next corresponding sub-record in actual values of the sub-records, a random access
to any record can not be made. On the other hand, when the relation between the
sub-records is established, a storage address of the sub-record is not understood
as far as a sub-record positioned just before the sub-record having a storage address
is not inputted except the sub-record including an item which is a key for storage
of the record and accordingly parallel input of sub-records can not be made.
On the contrary, when the records are of the variable length type and the records
are divided to be stored in a plurality of files on condition of the maximum record
length, an actual value of record having a short record length has no or less data
to be stored in a rear divided file. Accordingly, actual values of sub-record having
all or many useless areas are formed and the space efficiency of the rear divided
file is deteriorated.
It is an object of the present invention to provide a data processing method
and
apparatus capable of processing long data effectively at high speed with minimum
input/output process using a limited input/output buffer area.
It is a second object of the present invention to provide a data processing method
capable of dividing long data into a plurality of sub-records to be stored and
making operation of data in unit of sub-record.
It is a third object of the present invention to provide a data processing method
capable of dividing variable length data into a plurality of sub-records effectively.
It is a fourth object of the present invention to provide a data processing method
capable of dividing variable length data into a plurality of sub-records, storing
the divided sub-records in a plurality of memory units dispersedly and accessing
the stored data at high speed.
In order to achieve the above object, according to the present invention, a record
constituting a unit of data operation is divided into a plurality of sub-records
and the divided sub-records are stored in memory units, each capable of performing
independent input and output process, in unit of sub-record. The number of sub-records
necessary for required data operation is limited to the minimum and the data operation
is performed in unit of one or more sub-records. The size of divided sub-records
is desirably determined on the basis of unit of access to the memory unit for storing
the sub-records. For example, when an external memory unit is a magnetic disk unit,
access of data is controlled in accordance with a physical record length of the
magnetic disk unit and accordingly if the size of divided sub-records is determined
in accordance with the physical record length, recording/reproducing operation
is made effectively at high speed.
The divided sub-records are stored in the memory units, each capable of performing
independent input and output process, in unit of sub-record. It is desirable to
store the plurality of sub-records in a plurality of memory units in parallel.
The memory unit desirably uses an array type magnetic disk unit. Storing of sub-records
can be made at higher speed by making storage addresses for the plurality of memory
units identical. For example, when first to third sub-records are stored in three
memory units, if storage addresses thereof are arranged properly so that the first
sub-record is stored in a record #1 of the first memory unit, the second sub-record
is stored in a record #1 of the second memory unit and the third sub-record is
also stored in a record #1 of the third memory unit, the same physical addresses
are desirably designated at the same time upon reading.
File definition information including configuration item information of record,
information indicative of a division unit of sub-records and selection information
indicative of a file of an external memory unit in which a divided sub-record is
stored is registered or stored in, for example, an external memory unit and data
processing is made with reference to the file definition information.
In the data processing method according to the present invention, by inputting
and outputting all sub-records in parallel in the operation of a record divided
and stored in unit of sub-record, data operation in unit of record can be attained.
On the other hand, when the number of required sub-records is limited to small
in accordance with the required data operation, an amount of input/output buffers
required in the data operation and the number of input/output operations to the
memory unit can be reduced as compared with the case where all sub-records are
processed in unit of record.
In file definition information registration/reference means of the data processing
apparatus according to the present invention, since the file definition information
indicative of the relation of divided sub-records of the record and files corresponding
to the divided sub-records is provided in a register or roster, the file definition
information can be referred on the extension of the record operation instruction.
Thus, parallel input/output of all sub-records as well as individual input/output
of each of the sub-records can be made upon execution of the record operation instruction.
Further, since a file in which each of the sub-records is stored can be selected
arbitrarily, the external memory unit can be selected in accordance with the access
characteristic of each of the sub-records such that the sub-record having high
access frequency uses a semiconductor memory unit having high-speed input/output
possibility, so that the performance of the whole system can be improved.
The above method is suitable for the case of the fixed length record, while the
method for the variable length record is made as follows. That is, the record is
divided into a fixed length portion and a variable length portion. The fixed length
portion may be stored as described above. The variable length portion is further
divided into different sub-records to be stored in the memory unit. Since the sub-record
of the variable length portion has a length varied in accordance with data to be
written, a data length can not be fixed. Accordingly, it is difficult to make identical
the storage address with that of the memory unit for storing the fixed length sub-record.
Thus, in the present invention, the physical address for storage of the variable
length portion is not made identical with that of other sub-records and a pointer
indicative of the storage address is stored in a portion of the fixed length sub-record
to thereby designate a reading position of data in the variable length portion.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram illustrating a file management system according
to an embodiment of the present invention;
FIG. 2 illustrates an example of a data storage method in the file management
system of the embodiment;
FIG. 3 illustrates an example of a data structure of a record management table
in the file management system of the embodiment;
FIG. 4 is a flow chart showing a process of a record operation instruction execution
processing unit of the embodiment;
FIG. 5 is a flow chart showing a process of a record retrieval processing unit
of the embodiment;
FIG. 6 is a flow chart showing a process of a sub-record retrieval process of
the embodiment;
FIG. 7 is a flow chart showing a process of a sub-record selection processing
unit of the embodiment;
FIG. 8 is a flow chart (part 1) showing a process of a record update
processing unit of the embodiment;
FIG. 9 is a flow chart (part 2) showing a process of the record update
processing unit of the embodiment;
FIG. 10 is a flow chart (part 3) showing a process of the record update
processing unit of the embodiment;
FIG. 11 is a flow chart showing a process of a record deletion processing unit
of the embodiment;
FIG. 12 is a flow chart (part 1) showing a process of a record storage
processing unit of the embodiment;
FIG. 13 is a flow chart (part 2) showing a process of the record storage
processing unit of the embodiment;
FIG. 14 is a flow chart showing a procedure of a search process of a unit-of-sub-record
input/output buffer management processing unit of the embodiment;
FIG. 15 is a flow chart showing a procedure of a return process and a release
process of the unit-of-sub-record input/output buffer management processing unit
of the embodiment;
FIG. 16 is a flow chart showing a procedure of a securing process of the unit-of-sub-record
input/output buffer management processing unit of the embodiment;
FIG. 17 is a flow chart showing a procedure of an input process of a unit-of-sub-record
parallel input/output processing unit of the embodiment; and
FIG. 18 is a flow chart showing a procedure of an output process of the unit-of-sub-record
parallel input/output processing unit of the embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENT
An embodiment of the present invention is now described in detail with reference
to the accompanying drawings.
FIG. 1 is a schematic diagram illustrating a file management system according
to an embodiment of the present invention. The file management system
10
is to perform writing and reading processes of data
2 to an external memory
unit
20, and divides long data to perform various processes such as retrieval,
update, deletion and storage of data in unit of divided data (hereinafter referred
to "sub-record"). The data
2 is to be stored in the external memory unit
20. In FIG. 1, three sets of data (#
1, #
2 and #
3) are
illustrated, while the file management system
10 can divide the data by
a proper unit in accordance with the length of the given data and accordingly the
length of the data
2 and the peculiar structure of a record are not an important
problem. The external memory unit
20 is a memory unit for storing the data
2 and can use various memory units such as, for example, a magnetic disk
unit, an optical disk unit and a magnetic tape unit. The external memory unit
20
includes a plurality of memory means capable of being accessed simultaneously and
can desirably perform parallel transfer and parallel recording/reproducing of data.
A record operation instruction
1 is operation instructions such as retrieval,
update, deletion and storage and is specified together with unit of process by
a higher ranking apparatus, for example. A file definition parameter
3 is
to indicate a situation of the data
2 to be stored in the external memory
unit
20 and can specify a unit for dividing the data
2 into sub-records
and a memory location of a file in the external memory unit
20 in which
the data is stored. Information given by the file definition parameter
3
is registered in a file definition information roster
30 as file definition information.
The file management system
10 comprises a record operation instruction
execution unit
12 for controlling analysis and execution of the record operation
instruction
1, a record retrieval processing unit
13, a record update
processing unit
14, a record deletion processing unit
15 and a record
storage processing unit
16 responsive to a calling from the record operation
instruction execution processing unit
12 for performing various record operations,
a sub-record selection processing unit
17 for selecting a sub-record which
is actually required for various record operations, a unit-of-sub-record input/output
buffer management processing unit
18 for managing an input/output buffer
required for input/output of the sub-record, a unit-of-sub-record parallel input/output
processing unit
19 for performing input/output of data in unit of sub-record
between the external memory unit
20 and the unit-of-sub-record parallel
input/output processing unit
19, and a file definition information registration/reference
processing unit
11 for analyzing and editing the file definition parameter
3 to register it in the file definition information roster
30 and
capable of referring to the necessary file definition information in response to
calling from the record operation instruction execution processing unit
12.
The sub-record selection processing unit
17 automatically selects the
minimum sub-record required for record operation on the basis of the file definition
information when the unit of operation of the offered record operation instruction
is a unit of item or a unit of sub-record. The record retrieval processing unit
13 further includes a sub-record retrieval process
13a which
is also called commonly from the record update processing unit
14 and the
record deletion processing unit
15. In addition, the unit-of-sub-record
input/output buffer management processing unit
18 is divided into four processes
including search process, return process, securing process and release process,
the unit-of-sub-record parallel input/output processing unit
19 is divided
into two processes including input process and output process, and the file definition
information registration/reference processing unit
11 is divided into two
processes including reference process and registration process.
FIG. 2 illustrates an example of a data storage method in the file management
system according to the embodiment. A logical record data
50 includes a
portion constituted by fixed length information (sub-records
51,
52
and
53) and a portion constituted by variable length information (sub-record
54). The four sub-records
51,
52,
53 and
54
are stored in area
71,
72,
73 and
74 in external memory
units
21,
22,
23 and
24 capable of performing input/output
operation in parallel, respectively. Management of the storage is desirably made
in accordance with a physical record length which is a unit of physical input/output
of the external memory unit. For example, the sub-record
51 is stored in
physical records
81 and
82 of the area
71. It is desirable
that the physical records
81 and
82 are set to be physically continuous
records so as to increase a reading speed. Similarly, the areas
72,
73
and
74 include physically continuous records
82 and
83,
84
and
85, and
86,
87 and
88, respectively. The physically
continuous area corresponds to one cylinder of a magnetic disk unit, for example,
and represents an area in which continuous input/output of the physical records
in the area is made mechanically at high speed.
Since the sub-records
51,
52 and
53 are fixed length data,
the physically continuous areas
71,
72 and
73 have a physically
equal length and the sub-records are stored in the same physical address. In other
words, the physical records
80 and
81 are assigned to first and second
cylinders of the external memory unit
21, respectively. Similarly, the physical
records
82 and
83 are assigned to first and second cylinders of the
external memory unit
22, respectively. Further, the physical records
84
and
85 are assigned to first and second cylinders of the external memory
unit
23, respectively. Thus, by arranging the physical addresses for storage
in this manner, when the external memory units
22 to
23 are constituted
by disk units rotated in synchronism with each other, operation speed is improved remarkably.
On the contrary, the sub-record
54 is a variable length data portion,
and
physical length and physical address of the area
74 are not necessarily
identical with those of the areas
71,
72 and
73. This reason
is that the sub-record
54 of the logical record data
50 includes
three units of data
141 to
143 while the number of units is increased
or decreased depending on data to be handled. Accordingly, a pointer
75
indicative of a storage address of the physical record
86 of the area
74
in which the sub-record
54 of the variable portion is stored is set in the
physical record
85 of the area
73 in which the final sub-record of
the fixed portion is stored, to thereby form correspondence between the sub-records.
Similarly, the logic record data
60 is also divided into fixed
length sub-records
61,
62 and
63 and a variable length sub-record
64, which are stored in areas
91,
92,
93 and
94
of the external memory units
21,
22,
23 and
24 capable
of performing input/output operation in parallel, respectively. A pointer
95
indicative of an address of the variable length sub-record
64 in the external
memory unit
24 is set in the area
93, so that the fixed length data
portion (fixed portion) of the logical record data
60 corresponds to the
variable length data portion (variable portion) thereof.
Operation of the file management system
10 of FIG. 1 is now described.
When the file definition information registration/reference processing unit
11 registers the file definition information, a designated file definition
parameter
3 is supplied to the file definition information registration/reference
processing unit
11. The file definition parameter
3 includes information
such as a record name, a fixed/variable length type, a record length/maximum record
length, sub-record names, a sub-record length and sub-record storage file names.
The inputted information is edited by the file definition information registration/reference
processing unit
11 and is registered in the file definition information
roster
30 in the data format shown in FIG.
3.
In FIG. 3, a record management table
45 includes a header portion
46
having information relative to the whole data (record) and an entry portion
47
having information relative to divided sub-records. The entry portion
47
is arranged in an array including entries the number of which is equal to that
of sub-records constituting the record.
Referring now to FIG. 4, operation of the record operation instruction
execution processing unit
12 is described. When the record operation instruction
1 is inputted, the record operation instruction execution processing unit
12 receives the record operation instruction and analyzes it (step
200).
If there is any error, an error process is made (steps
202 and
230)
and an error report is sent to a request source. If there is no error, whether
the record management table
45 for a designated record has been prepared
in the memory or not is judged (step
204). If the record management table
is not found in the memory (step
206), the file definition information registration/reference
processing unit
11 is called by reference request (step
208) and
the record management table
45 of the file definition information is loaded
in the memory to initialize the management flags
48 of all of the sub-records
(step
210). When the record management table
45 has been already
loaded in the memory, only the initialization of the management flags
48
of all of the sub-records of the record management table
45 is made (steps
206 and
212).
The designated record operation instruction is now analyzed. When it is a retrieval
instruction, the record retrieval processing unit
13 is called (steps
214
and
216). When it is an update instruction, the record update processing
unit
14 is called (steps
218 and
220). When it is a deletion
instruction, the record deletion processing unit
15 is called (steps
222
and
224). When it is a storage instruction, the record storage processing
unit
16 is called (steps
226 and
228). When it is an instruction
other than the above, the error process is made (step
230) and an error
report is sent to the request source. The above processes are described later.
Referring now to FIG. 5, operation of the record retrieval processing unit
13 is described. The record retrieval processing unit
13 judges whether
a retrieval condition is provided in the designated record operation instruction
1 or not (step
300). When the retrieval condition is not provided,
the sub-record selection processing unit
17 is called without designation
of the retrieval condition (step
302). Further, when the retrieval condition
is provided, the sub-record selection processing unit
17 is called with
designation of the retrieval condition (step
304) and a sub-record requiring
the retrieval is determined.
A storage address of the record to be retrieved is obtained in accordance with
a key item of the retrieval condition, a relation of the record to be retrieved
to a record which has been retrieved just before or a storage location of a top
record (step
306). Then, the sub-record retrieval process
13a
is called (step
308) to retrieve the sub-record. As a method of obtaining
the storage address of the record to be retrieved in accordance with the key item
of the retrieval condition, there is a method that an index is added to the key
item and an index record portion is binary-searched or correspondence of the key
item and the record storage address is calculated by the hash function.
In the retrieval of the sub-record by the above sub-record retrieval process
13a,
if there is the retrieval condition (step
310), whether the retrieved sub-record
satisfies all of the retrieval conditions or not is judged (step
312). When
it can not be judged in accordance with the retrieval condition that there is no
record satisfying the retrieval condition (step
318), the unit-of-sub-record
input/output buffer management processing unit
18 is called by return request
(step
320) and after the buffer is returned once, the processes subsequent
to the step
306 are repeated.
When it can be judged in accordance with a single condition of the key item
that there is no record satisfying the retrieval condition (step
318), an
error process is made (step
322). Then, the unit-of-sub-record input/output
buffer management processing unit
18 is called by return request (step
326)
and after the buffer is returned, an error report is sent to the request source.
When the retrieved sub-record satisfies all of the retrieval conditions (step
312),
the sub-record selection processing unit
17 is called without designation
of the retrieval condition (step
314) and the sub-record which is not required
for judgment of the retrieval condition is also selected. The sub-record retrieval
process
13a is called (step
316) to perform the retrieval.
When there is no retrieval condition in step
310 and when the record
satisfying the retrieval condition is not found in step
312 and subsequent
steps, the retrieved data is transferred to an area of the record retrieval instruction
issue source (step
324). The unit-of-sub-record input/output buffer management
processing unit
18 is then called by return request (step
326) and
the buffer is returned to finish the process.
Referring now to FIG. 6, operation of the sub-record retrieval process
13a is described.
In this operation, first of all, an entry is positioned at the top sub-record
of the record management table
45 (step
330) and whether a flag to
be operated is set or not is judged (step
332). When the flag to be operated
is set, the storage address of the record to be retrieved and the input request
flag are set to retrieve the sub-record (step
334). The unit-of-sub-record
input/output buffer management processing unit
18 is called by search request
(step
336) and whether the sub-record has been already inputted in the buffer
or not is judged. When the flag to be operated is not set, any operation is not made.
The above processes from steps
332 to
336 are repeated for all
sub-record entries of the fixed portion of the record management table
45
(steps
338 and
340). Then, in order to read all sub-records required
by the fixed portion, the unit-of-sub-record parallel input/output processing unit
19 is called by input request (step
342). Whether there is the variable
portion for definition of the record or not judged (step
344), and when
there is no variable portion, the process is finished.
On the other hand, when there is the variable portion, an entry is positioned
at the top sub-record of the variable portion of the record management table
45
(step
346) and whether the flag to be operated is set or not is judged (step
348). When the flag to be operated is not set, the process is finished,
while when the flag is set, whether a storage address of the variable portion is
present in the final sub-record of the fixed portion or not is judged (step
350).
When the storage address of the variable portion is not present, the process
is finished, while when the storage address of the variable portion is present,
the storage address is set in a storage address of the sub-record entry of the
variable portion and an input request flag is set (step
352). The same operation
is also made to the sub-record of the variable portion in the same manner as in
the fixed portion. That is, the unit-of-sub-record input/output buffer management
processing unit
18 is called by search request (step
354) and whether
the sub-record has been already inputted in the buffer or not is judged. Then,
the unit-of-sub-record parallel input/output processing unit
19 is called
by input request (step
356) to read out the sub-record and the process is finished.
Referring now to FIG. 7, operation of the sub-record selection processing
unit
17 is described.
In this operation, an entry is positioned at the top sub-record of the record
management table
45 (step
400) and the following process is repeated
for all of the sub-record entries of the record management table
45 (steps
424 and
426). When the request does not specify the retrieval condition
(step
402), whether a unit of operation of the record operation instruction
is a unit of item or a unit of sub-record is judged (step
406). When it
is neither the unit of item nor the unit of sub-record, that is, when it is a unit
of record, the flag to be operated is set in the sub-record entry (step
414).
When the unit of operation of the record operation instruction is the unit of
item or the unit of sub-record, whether the sub-record is a sub-record including
the unit-of-operation item or a sub-record of the unit-of-operation is judged (step
408) and when it is the sub-record including the unit-of-operation item
or the sub-record of the unit-of-operation, the flag to be operated is set in the
sub-record entry (step
414).
When it is neither the sub-record including the unit-of-operation item nor the
sub-record of the unit-of-operation, whether the sub-record is the final sub-record
of the fixed portion or not is judged (step
410). When it is the final sub-record
of the fixed portion and includes the variable portion which is a sub-record including
the unit-of-operation item or a sub-record of the unit-of-operation, the flag to
be operated is also set in the final sub-record entry of the fixed portion (step
414).
Then, when the request specifies the retrieval condition (step
402),
whether the sub-record is a sub-record including the retrieval condition item or
not is judged (step
416). When it is the sub-record including the retrieval
condition item, the flag to be operated is set in the sub-record entry (step
422).
When it is not the sub-record including the retrieval condition item, whether it
is the final sub-record of the fixed portion or not judged (step
418). When
it is the final sub-record of the fixed portion and includes the variable portion
which is a sub-record including the retrieval condition item (step
420),
the flag to be operated is set in the sub-record entry (step
422). When
the above process is made for all sub-record entries of the record (step
424),
the process is finished.
Referring now to FIGS. 8 to
10, operation of the record update processing
unit
14 is described.
First of all, whether the record or sub-record to be updated has been retrieved
just before or not is judged (step
500). When it has not been retrieved,
an error process is made (step
502) and an error report is sent to a request source.
When it has been retrieved, the sub-record selection processing unit
17
is called and the sub-record to be updated is selected (step
504). A storage
address of the record or sub-record which has been retrieved just before is obtained
(step
506) and the sub-record retrieval process
13a is called
(step
508) to retrieve all of sub-records to be retrieved.
Subsequently, an entry is positioned at the top sub-record of the record
management table
45 (step
510). With respect to all sub-record entries
of the fixed portion, when the flag to be operated is set (step
512), update
data is reflected to the sub-record inputted in the buffer (step
514) and
the process of setting the output request flag (step
516) is repeated for
all sub-records of the fixed portion (steps
518 and
520).
Then, whether there is a variable portion or not is judged (step
522).
When there is the variable portion, an entry is positioned at the top sub-record
of the variable portion of the record management table
45 (step
524)
and the process peculiar to the variable portion is made as follows.
When the flag to be operated is set in the sub-record of the variable portion
(step
526) and the buffer address is present (step
528), whether
the update data is longer than data which is not updated and inputted in the buffer
or not is judged (step
530). When it is longer, the storage address of the
sub-record of the data not updated is evacuated (step
532).
On the other hand, when the buffer address is not set (step
528), the
unit-of-sub-record
input/output buffer management processing unit
18 is called by securing
request (step
534) to secure the output buffer of the update data. An address
of an unoccupied area of the sub-record storage file of the variable portion is
obtained as a new storage location of the sub-record of the variable portion (step
536). The storage address of the sub-record entry and the storage address
of the variable portion in the final sub-record of the fixed portion are updated
by the address of the unoccupied area (step
538).
When the update data is shorter than data not updated (step
530), it
is not necessary to update the storage address. Then, the update data is reflected
to the buffer (step
540) and the output request flag is set (step
542).
After completion of the process peculiar to the variable portion and when there
is no variable portion (step
522), the unit-of-sub-record parallel input/output
processing unit
19 is called by output request (step
546) and the
update data is outputted. The unit-of sub-record input/output buffer management
processing unit
18 is called by return request (step
548) and the
data is left on the input/output buffer.
Then, whether the storage address of the sub-record not updated which is evacuated
at step
532 is present or not is judged (step
550). When it is not
evacuated, the process is finished. When it has been evacuated, an entry is positioned
at the top sub-record of the variable portion of the record management table
45
(step
552) and the storage address of the sub-record not updated which has
been evacuated is set as a storage address of the sub-record entry (step
554).
Then, the unit-of-sub-record input/output buffer management processing unit
18 is called by securing request (step
556) and the buffer is secured.
Further, an unoccupied record data is set (step
558) and the output request
flag is set (step
560). The unit-of sub-record parallel input/output processing
unit
19 is called by output request (step
562) and the area in which
the sub-record not updated has been stored is made unoccupied.
Further, the unit-of-sub-record input/output buffer management processing
unit
18 is called by release request (step
564) to release the buffer
and the process is finished.
Referring now to FIG. 11, operation of the record deletion processing unit
15 is described.
First of all, whether the record or sub-record to be deleted has been retrieved
just before is judged (step
600). When it has not been retrieved, an error
process is made (step
602) and an error report is sent to the request source.
When it has been retrieved, the sub-record selection processing unit
17
is called (step
604) and the sub-record to be updated is selected. The storage
address of the record or sub-record which has been retrieved just before is obtained
(step
606) and the sub-record retrieval process
13a is called
(step
608) to retrieve all of sub-records to be deleted.
Then, an entry is positioned at the top sub-record of the record management
table
45 (step
610). When the flag to be operated and the inputted
flag are set with respect to all of sub-record entries (step
612), the unoccupied
record data is reflected to the sub-record inputted in the buffer (step
614)
and the process of setting the output request flag (step
616) is repeated
(steps
618 and
620). Then, the unit-of-sub-record parallel input/output
processing unit
19 is called by output request (step
622) and unoccupied
record data is produced in all of sub-records to be deleted to thereby delete the record.
Finally, an entry is positioned at the top sub-record of the record management
table
45 again (step
624). Further, with respect to all of sub-record
entries, the unit-of-sub-record input/output buffer management processing unit
18 is called by release request (step
626) and after the process
of releasing the buffer is repeated (steps
628 and
630), the process
is finished.
Referring now to FIGS. 12 and 13, operation of the record storage processing
unit
16 is described.
First of all, the sub-record selection processing unit
17 is called
(step
700) and the storage address of the record is obtained for all of
sub-records on the basis of the key item, a relation of the record to a record
which has been retrieved just before or an address of an unoccupied area of the
sub-record storage file of the fixed portion (step
702). Then, an entry
is positioned at the top sub-record of the record management table
45 and
the following process is repeated for all of sub-record entries (steps
714
and
716).
When the sub-record is the fixed portion (step
706), the unit-of sub-record
input/output buffer management processing unit
18 is called by securing
request (step
708) and the buffer is secured. Then, the storage data is
transferred to the buffer (step
710) and the record storage address and
the output request flag are set (step
712). When the sub-record is the variable
portion (step
706), whether there is the storage data or not is judged (step
718) and when there is not the storage data, any operation is not made.
When there is the storage data, the unit-of-sub-record input/output buffer management
processing unit
18 is called by securing request (step
720) and the
buffer is secured. An address of unoccupied area of the sub-record storage file
of the variable portion is obtained and the storage address of the sub-record entry
and the variable portion storage address in the final sub-record of the fixed portion
are updated by the obtained address (step
724). Then, after the storage
data is transferred to the buffer (step
726), the output request flag is
set (step
728).
Finally, when the process for all of the sub-records has been completed
(step
714), the unit-of-sub-record parallel input/output processing unit
19 is called by output request (step
730) to store data. Then, the
unit-of-sub-record input/output buffer management processing unit
18 is
called by release request (step
732) and after the buffer is returned, the
process is finished.
Referring now to FIG. 14, the search process of the unit-of-sub-record
input/output buffer management processing unit
18 is described.
First of all, whether the buffer address has been set in the sub-record entry
of the designated record management table
45 or not is judged (step
800).
When it has not been set and when it has been set but the buffer is not an already
inputted buffer in buffer pool (step
812) or when the buffer is the already
inputted buffer in buffer pool but sub-record of storage address set in the sub-record
entry is not inputted (step
814), the sub-record having the storage address
set in the sub-record entry is searched for from the already inputted buffer in
the buffer pool(step
802).
As a result of the search, when it is found from the already inputted buffer
(step
804), the already inputted buffer is made an occupied buffer and the address
of the buffer is set in the buffer address of the sub-record entry (step
806).
Then, the already inputted flag is set (step
808) and the process is finished.
When it is not found from the already inputted buffer in the buffer pool (step
804), the unit-of-sub-record input/output buffer management processing unit
18 is called by securing request (step
810) and after a new buffer
is secured, the process is finished.
On the other hand, when the buffer of the buffer address designated by the sub-record
entry is the already inputted buffer in the buffer pool (step
812) and the
sub-record of the designated storage address is inputted (step
814), the
already inputted buffer is made an occupied buffer (step
816). Then, the
already inputted flag of the sub-record entry is set (step
808) and the
process is finished.
Referring now to FIGS. 15 and 16, the return process, the securing process
and the release process of the unit-of-sub-record input/output buffer management
processing unit
18 are described.
Operation of the return process is now described. An entry is positioned
at the top sub-record of the record management table
45 (step
820)
and when the buffer address has been set with respect to all of sub-record entries
of the record management table
45 (step
822), the process of returning
the buffer to the already inputted buffer in the buffer pool (step
824)
is repeated (steps
826 and
828).
Operation of the securing process is now described.
The buffer having a length equal to that of the sub-record set in the sub-record
entry of the record management table
45 is searched for from unoccupied
buffers in buffer pool (step
830). When it is found from the unoccupied
buffer (step
832), the buffer is made an occupied buffer and its address
is set in the buffer address of the sub-record entry (step
834). Then, the
already inputted flag and the already outputted flag are cleared (step
836)
and the process is finished.
When it is not found from the unoccupied buffer (step
832), the buffer
having a length equal to that of the sub-record set in the sub-record entry is
searched for from the already inputted buffers in the buffer pool (step
838).
When it is found from the already inputted buffer (step
840), setting of
the buffer address (step
834) and clearing of the flag (step
836)
are made similarly and the process is finished.
When it is not found even from the already inputted buffers (step
840),
a buffer lack error is issued (step
842) and the process is finished.
Operation of the release process is now described.
The buffer designated by the buffer address of the sub-record entry of the record
management table
45 is made an unoccupied buffer in the buffer pool (step
850). Then, the buffer address of the sub-record entry is cleared (step
852) and the process is finished.
Referring now to FIG. 17, the input process of the unit-of-sub-record parallel
input/output means
19 is described.
An entry is positioned at the top sub-record of the record management table
45
(step
900). Whether the input request flag and the already inputted flag
are set or not is judged for all of sub-record entries of the record management
table and when not set (step
902), the storage address of the sub-record
entry is converted into a physical address (step
904). Then, the process
of requiring input of the physical record to buffer set from the sub-record storage
file (step
906) is repeated (steps
908 and
910).
After the process for all of sub-record entries has been completed, Whether
all of sub-records required to be inputted have been inputted or not is judged
(step
912). If there is any sub-record not inputted, the process waits for
its input (step
914).
The completion of input/output of the sub-records is reported by an input/output
completion interrupt and the completed input/output request is investigated (step
918). Then, the input/output completion is reported to the input/output
request process (step
920).
After the input of all of sub-records required to be inputted has been completed,
an already inputted flag is set in the sub-record entry of all of sub-records required
to be inputted (step
916) and the process is finished.
Referring now to FIG. 18, the output process of the unit-of-sub-record
parallel input/output means
19 is described.
First of all, an entry is positioned at the top sub-record of the record management
table
45 (step
930). Whether the output request flag is set and the
already outputted flag is not set is judged with respect to all of sub-record entries
of the record management table and when the output request flag is set but the
already outputted flag is not set (step
932), the storage address of the
sub-record entry is converted into a physical address (step
934). Then,
the process of requiring to output the physical record from the buffer set in the
sub-record s
