Sets the designated parameter to SQL NULL. This version of the method setNull should be used for user-defined types and REF type parameters. Examples of user-defined types include: STRUCT, DISTINCT, JAVA_OBJECT, and named array types.

Note: To be portable, applications must give the SQL type code and the fully-qualified SQL type name when specifying a NULL user-defined or REF parameter. In the case of a user-defined type the name is the type name of the parameter itself. For a REF parameter, the name is the type name of the referenced type.

Although it is intended for user-defined and Ref parameters, this method may be used to set a null parameter of any JDBC type. If the parameter does not have a user-defined or REF type, the given typeName is ignored.

Parameters:

parameterName		the name of the parameter
sqlType		a value from java.sql.Types
typeName		the fully-qualified name of an SQL user-defined type; ignored if the parameter is not a user-defined type or SQL REF value

Exceptions:

SQLException		if parameterName does not correspond to a named parameter; if a database access error occurs or this method is called on a closed CallableStatement
SQLFeatureNotSupportedException		if the JDBC driver does not support this method

Since:  1.4