If the value of a column in a statement object is the SQL NULL value, then the getValue method will return a Java "null" value. The null value can be dangerous in Java, and cause runtime exceptions.

You must always check whether a value is null before attempting to assign the value from a statement object to a trigger's Java variable or to a new SQL statement input parameter. The OLDROW and NEWROW classes provide the isNULL method for this purpose.

The following example illustrates using the isNULL method:

If (OLDROW.isNULL(1))
          qryStrBuf.append("StartDate is null "  + " AND ");
      else
          qryStrBuf.append("StartDate = '" + OLDROW.getValue(1,0).toString() + "' AND ");

col_num

Specifies the integer column number of the affected row. getValue retrieves the value in the column denoted by col_num. 1 denotes the first column of the table that the trigger is for. 2 denotes the second, n denotes the nth.