MySQL 8.0 Reference Manual Including MySQL NDB Cluster 8.0
The user_defined_functions table
contains a row for each user-defined function (UDF) registered
automatically by a component or plugin, or manually by a
CREATE
FUNCTION statement. For information about operations
that add or remove table rows, see
Section 5.7.1, “Installing and Uninstalling User-Defined Functions”.
The user_defined_functions table
has these columns:
UDF_NAME
The UDF name as referred to in SQL statements. The value
is NULL if the function was registered
by a CREATE FUNCTION
statement and is in the process of unloading.
UDF_RETURN_TYPE
The UDF return value type. The value is one of
int, decimal,
real, char, or
row.
UDF_TYPE
The UDF type. The value is one of
function (scalar) or
aggregate.
UDF_LIBRARY
The name of the library file containing the executable UDF
code. The file is located in the directory named by the
plugin_dir system
variable. The value is NULL if the UDF
was registered by a component or plugin rather than by a
CREATE FUNCTION statement.
UDF_USAGE_COUNT
The current UDF usage count. This is used to tell whether statements currently are accessing the UDF.
The user_defined_functions table
has these indexes:
Primary key on (UDF_NAME)
TRUNCATE TABLE is not permitted
for the user_defined_functions
table.