TPF blurs the boundaries between traditional databases and operating system. The OS itself has built-in support for transactions, locking of records, processing of record streams and other database-y things. So while strictly speaking, yes TPF is an OS, it is an OS that is designed to be a database, and would be useless for most other purposes.
Sure code still needs to be run on top of it for specific reasons, but I submit for consideration this is true of SQL databaes, and the data persistence layer of any NoSQL based app.
Similarly CICS may have a relational DB in the loop, or it may be pointing at some sort of TPF based system, or it could be pointing at a simple pile of COBOL records stored in z/VSE. The point is CICS is the transaction manager and provides the interface to the data much the same way an sql layer over a relational DB does.
Sure code still needs to be run on top of it for specific reasons, but I submit for consideration this is true of SQL databaes, and the data persistence layer of any NoSQL based app.
Similarly CICS may have a relational DB in the loop, or it may be pointing at some sort of TPF based system, or it could be pointing at a simple pile of COBOL records stored in z/VSE. The point is CICS is the transaction manager and provides the interface to the data much the same way an sql layer over a relational DB does.