| 摘要 |
PURPOSE:To execute a retrieval processing even in case when a field which becomes an object of a retrieval operation does not exist in a record, by providing a means for generating a artificial field, and a recognizing means of the artificial field on a retrieval operating circuit. CONSTITUTION:When executing a retrieval, a cue control part 8 extracts a field required for an operation, from in each logical record in an input buffer 12, and sets it to a field cue 13. In this case, in case when a field which becomes an object of an operation does not exist, a artificial field whose length is 2 bytes and whose description contents are 2 is generated and set. A retrieval operating part 6 compares the contents of a constant cue 4 and a field cue 13, and reports its operation result to a retrieval control part 2 at a logical record unit. A artificial field monitoring part 17 monitors whether the first 2 bytes of the fields are 2 or not, and if they are 2, it is discriminated to be a artificial field, it is reported to the retrieval operating part 6, and an instruction by which an operation to its field is not formed is executed.
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