A Teradata ML Engine user-defined function (UDF) is a programming construct that accepts parameters, uses the accepted parameters, and returns a result. These functions use the syntax and APIs similar to Teradata ML Engine functions. Teradata ML Engine does not support the development of these functions. However, if you have a UDF developed on Aster Database, you can install and execute it in Teradata ML Engine. The execution of a UDF is the same as Teradata ML Engine function execution. A UDF invocation gets its data from Teradata SQL Engine, executes in the Teradata ML Engine, and returns the results to Teradata SQL Engine.