ALTER statements are used to modified a registered table/view/function definition in the Catalog.
Flink SQL supports the following ALTER statements for now:
Run an ALTER statement
ALTER statements can be executed with the executeSql() method of the TableEnvironment, or executed in SQL CLI. The executeSql() method returns ‘OK’ for a successful ALTER operation, otherwise will throw an exception.
The following examples show how to run an ALTER statement in TableEnvironment and in SQL CLI.
Rename the given table name to another new table name.
Set or Alter Table Properties
Set one or more properties in the specified table. If a particular property is already set in the table, override the old value with the new one.
Set one or more properties in the specified database. If a particular property is already set in the database, override the old value with the new one.
Alter a catalog function with the new identifier and optional language tag. If a function doesn’t exist in the catalog, an exception is thrown.
If the language tag is JAVA/SCALA, the identifier is the full classpath of the UDF. For the implementation of Java/Scala UDF, please refer to User-defined Functions for more details.
If the language tag is PYTHON, the identifier is the fully qualified name of the UDF, e.g. pyflink.table.tests.test_udf.add. For the implementation of Python UDF, please refer to Python UDFs for more details.
Alter temporary catalog function that has catalog and database namespaces and overrides catalog functions.
Alter temporary system function that has no namespace and overrides built-in functions
If the function doesn’t exist, nothing happens.
Language tag to instruct flink runtime how to execute the function. Currently only JAVA, SCALA and PYTHON are supported, the default language for a function is JAVA.