When transforming legacy programs into fully equivalent programs in modern technology that use a relational database, special attention is required to implement the mapping of the data access statements to read, update, delete and insert data in the various legacy data stores. These data stores - such as IDMS, UDS, IMS, ADABAS, and VSAM, are not accessed through SQL syntax like you would use for an RDBMS. Instead, each data store provides the developer with dedicated syntax (typically called DML statements where DML stands for Data Manipulation Language) to access the data in all necessary ways.

Read the full article here to get some insight in the design concepts of how CodeTurn handles data access!