This topic describes the LRF DML statements in CA IDMS/DB database and CA IDMS/DC and CA IDMS UCF data communication environments. Most data communication DML statements apply to CA IDMS/DC and CA IDMS UCF (DC/UCF) environments.
This information applies to PL/I programmers who run programs against CA IDMS/DB databases and who use the DC/UCF system facilities.
The CA IDMS Data Manipulation Language (DML) consists of statements that direct CA IDMS/DB database and data communications processing. You code DML statements in the program source as if they are a part of the host language. You use the DML PL/I compiler (also called the DMLP processor) to convert DML statements into standard PL/I statements. The DMLP processor also performs source-level error checking.
Your program uses different sets of DML statements, depending on whether its operating environment is batch or online. A batch program uses only database DML statements. An online program uses data communications DML statements and can also use database DML statements.
Batch processing typically involves large volumes of transactions, sequential processing, and output in the form of files and reports. Batch programs use database DML statements only. Data Manipulation Language Statements contains all the DML commands, listed alphabetically. In this list, CA IDMS/DC DML commands are distinguished from CA IDMS/DB DML commands.
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.
Online processing typically involves transaction requests entered from terminals connected directly to the computer, transaction results displayed at the terminal, multiple requests from multiple sources, and sharing one copy of a program among multiple users. Online processing is immediate. The processing of large volumes of transactions from multiple online users requires fast response time. 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.