Rules for Writing UDFs that Compress/Decompress LOB Data - Advanced SQL Engine - Teradata Database

• The compress UDF should have the following signature:
  • The scalar UDF must declare a single input parameter which has a data type of BLOB, CLOB, or supported distinct LOB-type UDT.
  • The parameter data type and column data type should be the same.
  • The return type should be BLOB.
• The decompress UDF should have the following signature:
  • The scalar UDF must declare a single BLOB input parameter. The length of the input parameter should be equal to or greater than the length of the BLOB data type returned by the compression UDF.
  • The output of the decompress UDF should be identical to the column type.