Introduction to CA IDMS Data Manipulation Language (COBOL)

The CA IDMS data manipulation language (DML) consists of statements that direct CA IDMS database (DB) and data communications (DC) processing. DML statements are coded in the program source as if they were a part of the host language. The precompiler converts DML statements into standard COBOL statements and performs source-level error checking.
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The CA IDMS data manipulation language (DML) consists of statements that direct CA IDMS database (DB) and data communications (DC) processing. DML statements are coded in the program source as if they were a part of the host language. The precompiler converts DML statements into standard COBOL statements and performs source-level error checking.
The operating environment determines which DML statements your program uses. A batch program uses only database DML statements, but an online program uses both database and data communications DML statements.
  • Batch processing
    typically involves large transaction volumes, sequential processing, and output in the form of files and reports. Batch programs use database DML statements only.
    The following figure illustrates the flow of a typical batch application. Input to DEPTRPT consists of department IDs. Output consists of a listing of departments and their employees. The error report lists the department IDs of missing and empty departments.
    This figure illustrates the flow of a typical batch application. Input to DEPTRPT consists of department IDs. Output consists of a listing of departments and their employees. The error report lists the department IDs of missing and empty departments.
  • Online processing
    typically involves transaction requests that are entered from terminals that are connected directly to the computer, transaction results that are displayed at the terminal, multiple requests from multiple sources, and sharing one copy of a program among multiple users. Also, online processing is immediate. Fast response time is essential when processing large transaction volumes from multiple online users. Online programs use data communications DML statements and can include database DML statements.
    The following figure illustrates the flow of a typical online application. EMPDISP retrieves information for an operator-specified employee ID. Output to the terminal consists of DEPARTMENT, EMPLOYEE, JOB, and OFFICE information.
    This figure illustrates the flow of a typical online application. EMPDISP retrieves information for an operator-specified employee ID. Output to the terminal consists of DEPARTMENT, EMPLOYEE, JOB, and OFFICE information.