JPH06103324A - Data storage system - Google Patents

Abstract

PURPOSE:To prevent a data storage program from ending abnormally owing to the generation of an exception due to mismatching with definition information when data on a magnetic tape are stored in a data base file. CONSTITUTION:A data item length deciding means 4 compares the length of data in external format inputted from the magnetic tape 14 by a data/data item length input means 3 with the definition information developed on a main storage device 13 by a definition information acquiring means 2 to decide their matching. If there is the possibility that an exception is generated by conversion like a data length discrepancy, discrepancy information is outputted to an error information stack 15, but a data converting means 5 performs conversion with data length based upon the definition information to prevent the exception.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data storage system, and more particularly to a data storage system for storing data recorded on a magnetic tape in a database file on a magnetic disk device.

[0002]

2. Description of the Related Art Conventionally, in this type of data storage method, a name given to definition information representing a data structure of a target data in a database file is inputted from an input device, and the table name is given. The definition information is extracted from the directory file and expanded on the main storage device. Then, in order to input the external format data recorded on the magnetic tape and store the input external format data in the database file on the magnetic disk device, according to the definition information expanded on the main storage device. The data is converted into the internal format and the converted internal format data is output to the database file on the magnetic disk device.

[0003]

In the conventional data storage system described above, the data recorded on the magnetic tape is
It is assumed that the definition information is consistent with the definition information stored in the directory file, and then the data format is converted according to the attribute. Therefore, if the user mistakenly specifies the table name of the definition information with a different attribute structure or stores the data on the magnetic tape and then changes the definition information, the attribute structure changes. , There is a case that data cannot be stored due to mismatch of item length, the program causes an exception when storing the data, and it ends abnormally, so the table itself remains in the database file in an incorrect form. It has the drawback that the table cannot be handled by the user program.

[0004]

A data storage system of the present invention is a data storage for converting external format data recorded on a magnetic tape into a predetermined attribute and storing it in a database file on a magnetic disk device. In the method, the table name input means for inputting the name given to the definition information representing the data structure in the database file of the target data from the input device, and the table name obtained by this table name input means were provided. Definition information acquisition means for extracting the definition information from the directory file and expanding it on the main memory; data / data item length input means for inputting the external format data recorded on the magnetic tape and its length; The length of each data item obtained by the data item length input means and the definition information expanded on the main memory by the definition information acquisition means. Of the data item length determining means for determining the consistency with the respective item lengths, and displaying an error when a mismatch is detected, and when the data item length determining means detects a length mismatch, Data conversion means for converting the data in the external format recorded on the tape into a form adapted to the length of the data item on the main storage device, and data for outputting the data converted by this data conversion means to a database file And output means.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention.
In the embodiment shown in FIG. 1, table name input means 1, definition information acquisition means 2,
Data / data item length input means 3, data item length determination means 4, data conversion means 5, data output means 6, input device 11, directory file 12, main storage device 13, magnetic tape 14, error information stack 15, and database It is configured to have a file 16.

The table name input means 1 inputs the table name given to the definition information from the input device 11. The definition information acquisition means 2 takes out the definition information having the same table name as the table name obtained by the table name input means 1 from the directory file 2 and expands it on the main storage device 13. The data / data item length input means 3 inputs the external format data recorded on the magnetic tape 14 and its length. The data item length determination means 4 can compare the length of the data in the external format input by the data / data item length input means 3 with the item length of the definition information existing in the main storage device 13 and convert it into the internal format. Whether it is possible or impossible is determined, and if a length mismatch is detected, the fact is output to the error information stack 15. The data converting means 5 converts the data in the external format into the data in the internal format, but the data in the external format, which is judged by the data item length judging means 14 to have a mismatch in the data item length, is also expanded in the main storage device 13. It is converted according to the length based on the definition information. The data output means 6 outputs the data converted into the internal format by the data conversion means 5 to the database file 16.

FIG. 2 is a diagram showing the format and contents of various information and data handled in the embodiment of FIG. The processing of the embodiment shown in FIG. 1 will be described below with reference to FIG. First, it is assumed that the table name input means 1 receives from the input device 11 a table name added to the definition information indicating the attribute structure of the data to be stored in the database file 16, for example, "Table01". Figure 2 (a)
Is an example of contents of a plurality of definition information stored in the directory file 12, and the definition information acquisition means 2 uses the table name "Tab".
The definition information of "le01" is extracted from the directory file 12 and expanded in the main storage device 13. FIG. 2B shows an example of the contents of the definition information expanded in the main storage device 13, which follows the table name. The item length and the data attribute are repeated, the attribute CH being the character format and the PD being the packed 10
The decimal format and UD mean the unpacked decimal format. Next, the data / data item length input means 3 inputs the external format data recorded on the magnetic tape 14 and its length. FIG. 2C shows an example of the format and contents of the data on the magnetic tape. A 1-byte field indicating the length of data storage at the beginning and then the data of that length are repeated as a pair. Has been. C1, C2 in the figure
˜F1 and F2 represent data in EBCDIC code representation. The data item length determination means 4 compares the length of each data item input from the magnetic tape 14 with the length of each data item of the definition information expanded on the main storage device 13 to determine the consistency. . In the example of the definition information of FIG. 2B and the data on the magnetic tape of FIG. 2C, the length of the head data input from the magnetic tape 14 and the length of the head data item of the definition information are both “03”. The judgment is true with ", indicating the data length after the next data on the magnetic tape 1
Since the byte is "03" and the definition information is also "03", the determination is true here as well. Similarly, the length of the next data item is true with "02" together with the magnetic tape and the definition information. Therefore, the data item length determination means 4 determines that the external format and the internal format can be converted without contradiction. next,
The data converting means 5 converts the external format of the magnetic tape into the internal format according to the definition information. FIG. 2D is a diagram showing an example in which the data on the magnetic tape of FIG. 2C is converted according to the definition information of FIG. 2B, and the 3 bytes indicated by “03” in the first character format are unchanged. Then, the next 3 bytes indicated by packed decimal format "03" are 4 bits each
2, 3 and C code which means + are converted, and the next 2 bytes indicated by "02" in the unpacked decimal format are output as they are. The data output unit 6 stores the data output from the data conversion unit 5 in the database file 16
To store.

Next, assuming that the structure of the data recorded on the magnetic tape 14 is different from the structure of the definition information expanded on the main storage device 13, the definition information is stored after the data is stored on the magnetic tape 14. Convert it to "Table02"
The table is stored in the database file 16. In this case, the table name input unit 1 receives "Table02" as the table name of the definition information from the input device 11, and the definition information acquisition unit 2 extracts the definition information having the input "Table02" as the table name from the directory file 14. ,
It is expanded on the main storage device 13. FIG. 2E is a diagram showing the contents of “Table02” expanded on the main storage device 13. Next, the data / data item length input means 3 inputs data from the magnetic tape 14. FIG. 2 (f) is a diagram showing an example of the data of the external format input from the magnetic tape 14 and the data of its length in this case. Here, the data item length determination means 4 compares the length of each data item input from the magnetic tape 14 with the length of each data item of the definition information loaded on the main storage device 13 to check the consistency. Judge. In this case, the length of the first data item input from the magnetic tape 14 is “03”, whereas the length of the first data item of the definition information is “02”. Therefore, it is determined that they do not match, and a message to that effect is output to the error information stack 5. On the other hand, the data conversion means 5 includes the data C1, which is determined by the data item determination means 14 as a data item mismatch.
2 for C2 and C3 according to "02" specified in the definition information
Only bytes are taken out, and the following data F1 and F2 are directly converted to the internal format because the definition information and the data item length of the magnetic tape are both "02". FIG. 2 (g) shows an example of data output by the data conversion means 5 in this case. Data C3 is lost by this conversion,
Since the next item data F1 and F2 are correctly converted, the data inconsistency is limited to only the first item, and the loss of the entire table can be prevented.

[0010]

As described above, according to the present invention, when the external format data recorded on the magnetic tape is converted into the attribute according to the specified definition information, the magnetic tape of the data is converted before the conversion. It is determined whether the length when stored in the memory and the length in the definition information match, and if they do not match, conversion is performed according to the definition information in the main storage device, and exceptions that occur during data conversion are detected beforehand. Even if the user mistakenly inputs a table name with definition information different from the structure of the data on the magnetic tape from the input device or changes the definition information after storing the data on the magnetic tape. , It is possible to avoid the abnormal termination of the program due to the occurrence of an exception and to leave the incorrect information in the database file, so that the user program can no longer handle the table. There is an effect.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a diagram showing a format and an example of contents of information in each means of the embodiment of FIG.

[Explanation of symbols]

 1 table name input means 2 definition information acquisition means 3 data / data item length input means 4 data item length determination means 5 data conversion means 6 data output means 11 input device 12 directory file 13 main storage device 14 magnetic tape 15 error information stack 16 Database file

Claims (1)

[Claims] 1. A data storage system for converting data of an external format recorded on a magnetic tape into a database file on a magnetic disk device after converting the data into a predetermined attribute and storing the target data from an input device. A table name input means for inputting the name given to the definition information representing the data structure in the file, and the definition information with the table name obtained by this table name input means are taken out from the directory file and stored in the main memory. Definition information acquisition means to be expanded, data / data item length input means for inputting the external format data recorded on the magnetic tape and its length, and each data item obtained by this data / data item length input means And the length of each item of the definition information expanded on the main storage device by the definition information acquisition means. , A data item length determining means for displaying an error when a mismatch is detected, and when the data item length determining means detects a length mismatch, the external format data recorded on the magnetic tape is used as the main data A data storage system characterized by having data conversion means for converting the data into a form according to the length of a data item on the storage device, and data output means for outputting the data converted by the data conversion means to a database file. .