This article explains how to use common commands to operate functions in the MaxCompute client.
You can also operate functions using the visualized online data development tools in DataWorks. For more information, see Function Management.
Create a Function
CREATE FUNCTION <function_name> AS <package_to_class> USING <resource_list>;
- function_name: An UDF name referenced in SQL.
- package_to_class: For Java UDF, this name is a fully qualified class name (from top-level package name to UDF class name). This parameter must be in double quotation marks. And, for Python UDF, this name is a python script name. classname. For both Java UDF and python script, use double quotation (““) marks to indicate this parameter. And for the name, use quotation marks.
- resource_list: Provides resource list used by UDF.
- Resources that contain UDF code must be included in the list.
- If the code reads the resource file by the distributed cache interface, this list also contains the list of resource files read by the UDF.
- The resource list is composed of multiple resource names, separated by a comma (,). The resource list must be in double quotation (“”) marks.
- Specify the project in which the resource is located as follows:
- Suppose a Java UDF class org.alidata.odps.udf.examples.Lower is in my_lower.jar, create function my_lower as follows:
CREATE FUNCTION test_lower AS org.alidata.odps.udf.examples.Lower USING my_lower.jar; USING 'my_lower.jar';
- Suppose a Python UDF MyLower is used in project pyudf_test.py,create function my_lower as follows:
create function test_lower as 'pyudf_test.MyLower' using 'test_project/resources/pyudf_test.py';
- Suppose a Java UDF class com.aliyun.odps.examples.udf.UDTFResource is in udtfexample1.jar, and it depends on file resource file_resource.txt and table resource table_resource1,create function test_udtf as follows:
create function test_udtf as com.aliyun.odps.examples.udf.UDTFResource using 'udtfexample1.jar, file_resource.txt, table_resource1,test_archive.zip';
- Similar to the resource files, the UDF duplicate name can be registered only once.
- Generally UDF cannot overwrite system built-in functions. Only the project owner has right to overwrite the built-in functions. If you are using a UDF which overwrites the built-in function, the warning is triggered in Summary after SQL execution.
Drop a Function
DROP FUNCTION <function_name>;
DROP FUNCTION test_lower;
list functions; --View all user-defined functions in current project. list functions -p my_project; --View all user-defined functions in the project 'my_project'.