code: private void setUniqueWhere(Where<DataColumnConstraints, Void> where,
  			String constraintName, DataColumnConstraintType constraintType,
  			String value) throws SQLException {
  
  		where.eq(DataColumnConstraints.COLUMN_CONSTRAINT_NAME, constraintName)
  				.and()
  				.eq(DataColumnConstraints.COLUMN_CONSTRAINT_TYPE,
  						constraintType.getValue());
  		if (value == null) {
  			where.and().isNull(DataColumnConstraints.COLUMN_VALUE);
  		} else {
  			where.and().eq(DataColumnConstraints.COLUMN_VALUE, value);
  		}
  
  	}
docs: Set the unique column criteria in the where clause
  
  @param where
  where clause
  @param constraintName
  constraint name
  @param constraintType
  constraint type
  @param value
  value
  @throws SQLException