Function names are distinct from specific function names, external function names, and function entry point names. See Function Name, Function Class Clause, EXTERNAL NAME Clause, and UDF Default Location Paths.
The following table briefly outlines the differences among the different function identifiers:
| Function Identifier | Syntax Variable Name | Definition |
|---|---|---|
| Function name | function_name | The identifier used to call the function from an SQL statement. If no specific name is assigned to the function, then the name stored in the data dictionary is function_name. If a specific name is assigned to the function, then function_name is not the name by which the dictionary knows the function as a database object, and it need not be unique within its database. |
| Specific function name | specific_function_name | The identifier used to define the function as a database object in the dictionary table DBC.TVM. |
| External function name | external_function_name | The external function name for a C or C++ external routine can be expressed in two ways:
An external function name is mandatory for a Java external routine when you specify JAVA in the Language clause. In this case, external_function_name is referred to as an external Java reference string. The external Java reference string specifies the JAR file, Java class within the JAR, and the Java method within the class that is to be invoked when the Java UDF is executed.
For example, if you have a JAR file that has been registered in the database with the ID salesreports, and the class within the JAR is named formal, and the method within the class to be called is named monthend, then the string salesreports:formal.monthend completely defines the exact method to invoke when the Java UDF is executed. |
| Function entry point name | function_entry_point_name | The identifier used to define the entry point name of the function. A function entry point name must be specified if its name is different than the function name or specific function names defined for the function. You cannot specify function_entry_ point_name more than one time in the EXTERNAL clause of the CREATE FUNCTION or REPLACE FUNCTION statements. |