VAX Rdb/VMS Guide to Data Manipulation

This manual provides comprehensive information on manipulating data within a VAX Rdb/VMS database, primarily using the Relational Database Operator (RDO) utility. Published in November 1987, it is intended for users familiar with data processing procedures, basic database management concepts, and the VMS operating system.

The guide is structured into seven chapters and two appendices, covering:

• Introduction to Rdb/VMS Data Manipulation: Concepts of data organization, the relational database model, and how to use RDO both interactively and programmatically.
• Accessing Databases and Transactions: Details on invoking databases, managing transactions with START_TRANSACTION (including READ_ONLY, READ_WRITE, and BATCH_UPDATE modes), and controlling data access and concurrency using various reserving options (SHARED, PROTECTED, EXCLUSIVE). It notes that Version 2.3 BATCH_UPDATE transactions no longer support ROLLBACK to prevent database corruption.
• Using Record Selection Expressions (RSEs): Techniques for selecting and displaying data, including sorting records, restricting the number of retrieved records using the FIRST clause, and specifying complex conditions with relational and logical operators (WITH clause, MATCHING, CONTAINING, range retrieval). It also covers eliminating duplicate values (REDUCED TO) and testing for unique record occurrences (UNIQUE).
• Retrieving Records and Joining Relations: Explanations of how to combine data from multiple relations or join a relation with itself (reflexive join) using the CROSS clause and nested FOR loops.
• Using Views and View Definitions: How to define and utilize stored queries (views) to simplify queries, restrict access to sensitive data, and create virtual relations from existing ones.
• Value, Arithmetic, and Statistical Expressions: Application of literals, arithmetic operations, and aggregate functions (such as AVERAGE, COUNT, MAXIMUM, MINIMUM, TOTAL) within RDO statements.
• Updating Databases: Instructions for storing, modifying, and erasing data using STORE, MODIFY, and ERASE statements, handling missing values with RDB$MISSING, and working with segmented strings. The START_STREAM statement is introduced for conditional record processing.

The manual features practical examples using a sample PERSONNEL database and highlights new features in Version 2.3, such as RDO command recall.