Registering a C UDR

The CREATE FUNCTION and CREATE PROCEDURE statements register user-defined functions and user-defined procedures, respectively, in the database. These functions store information about the UDR in the sysprocedures system catalog table.

Registration for a C UDR requires the following special clauses of the CREATE FUNCTION and CREATE PROCEDURE statements to help the database server identify the routine:

• The required EXTERNAL NAME clause specifies the path to the shared-object file that contains the compiled C code for the UDR.
• The required LANGUAGE clause specifies the language in which the body of the UDR is written.
• The optional WITH clause specifies the routine modifiers for the UDR.

For example, Figure 64 shows a CREATE FUNCTION statement that registers a user-defined function named abs_eq( ) whose corresponding C function is in a shared-object file named abs.so.

Figure 64. Registering a C UDR