In This Chapter

A C user-defined routine (UDR) is a UDR that is written in the C language and uses the server-side implementation of the DataBlade API to communicate with the database server. C UDRs (functions and procedures) are implemented as C-language functions. DataBlade modules often include C UDRs that are surfaced to DataBlade module users.

The development process for a C UDR follows these steps:

1. Design the use and development process for the UDR
2. Code a C routine that uses the DataBlade API functions to interact with the database server
3. Compile and link the C routine to create a shared-object file
4. Register the C routine with the CREATE FUNCTION or CREATE PROCEDURE statement
5. Execute the UDR
6. Use tracing and the debugging features to work out any problems in the UDR
7. Change any characteristics of the UDR that are required during its lifetime
8. Optimize performance of the UDR

This chapter describes each of these steps in the development of a C UDR. For general information on the development steps of a UDR, see the IBM Informix: User-Defined Routines and Data Types Developer's Guide.