Chapter 1: Introduction

Processing a cursor request

When a client sends a cursor request, a typical mainframe server application performs the tasks listed in Table 1-4.

**Table 1-4: Functions to process cursor requests**
Task	Function
1. Prepare for incoming requests. Initialize the Gateway-Library environment. Specify the type of IMS TM transaction (used with IMS TM transactions only).	TDINIT TDSETPT
2. Accept the incoming request. Accept the incoming request.	TDACCEPT
3. Determine the type of request. RPC, language, dynamic, or cursor.	TDINFPGM
4. Determine the type of cursor request. Retrieve CURSOR_COMMAND, CURSOR_ID, and COMMAND_OPTIONS.	TDCURPRO
5. Process the cursor request. Get SQL statement, number of parameters, table name, and parameters format. Either receive input parameters or update columns.	TDRCVSQL TDNUMPRM TDINFPRM TDRCVPRM
6. Describe the rows. Describe the rows. Send rows.	TDESCRIB TDSNDROW
7. Send return information. Send acknowledgment, CURSOR_STATUS, CURSOR_INFO.	TDCURPRO
8. Send DONE. Send a DONE package.	TDSNDDON
9. Accept the next request. Accept the incoming request.	TDGETREQ
10. End the conversation. Send final DONE package. Free the TDPROC structure. Free the MVS storage.	TDSNDDON TDFREE TDTERM