Sets the designated parameter to SQL NULL.

Note: You must specify the parameter's SQL type.

Parameters:

parameterName		the name of the parameter
sqlType		the SQL type code defined in java.sql.Types

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