Certain IMS™ concepts
are important to understand when using Structured Query Language (SQL).
Structured query language
One language that you use to access the data in IMS is SQL. SQL is a standardized
language for defining and manipulating data in a relational database.
IMS data structures for SQL
SQL support allows you to issue standard SQL query to access IMS data instead of using DL/I calls. To use SQL calls in IMS application, you
need to understand the difference between the hierarchical model for IMS databases and the standard relational database model since SQL calls are commonly used for
relational databases. You also need to understand how IMS database elements are being mapped to
relational database elements.