SQL Reference

Querying the Exception Tables

The message column structure in an exception table is a concatenated list of constraint names, lengths and delimiters as described earlier. You may wish to write a query on this information.

For example, let's write a query to obtain a list of all the violations, repeating each row with only the constraint name along with it. Let us assume that our original table T1 had two columns C1 and C2. Assume also, that the corresponding exception table E1 has columns C1, C2 pertaining to those in T1 and MSGCOL as the message column. The following query (using recursion) will list one constraint name per row (repeating the row for more than one violation):

WITH IV  (C1, C2, MSGCOL, CONSTNAME, I, J) AS
 (SELECT C1, C2, MSGCOL,
     CHAR(SUBSTR(MSGCOL, 12,
                 INTEGER(DECIMAL(VARCHAR(SUBSTR(MSGCOL,7,5)),5,0)))),
     1,
     15+INTEGER(DECIMAL(VARCHAR(SUBSTR(MSGCOL,7,5)),5,0))
    FROM E1
  UNION ALL
  SELECT C1, C2, MSGCOL,
      CHAR(SUBSTR(MSGCOL, J+6,
                  INTEGER(DECIMAL(VARCHAR(SUBSTR(MSGCOL,J+1,5)),5,0)))),
      I+1,
      J+9+INTEGER(DECIMAL(VARCHAR(SUBSTR(MSGCOL,J+1,5)),5,0))
    FROM IV
    WHERE I < INTEGER(DECIMAL(VARCHAR(SUBSTR(MSGCOL,1,5)),5,0))
 ) SELECT C1, C2, CONSTNAME FROM IV;

If we want all the rows that violated a particular constraint, we could extend this query as follows:

WITH IV  (C1, C2, MSGCOL, CONSTNAME, I, J) AS
 (SELECT C1, C2, MSGCOL,
      CHAR(SUBSTR(MSGCOL, 12,
                  INTEGER(DECIMAL(VARCHAR(SUBSTR(MSGCOL,7,5)),5,0)))),
      1,
      15+INTEGER(DECIMAL(VARCHAR(SUBSTR(MSGCOL,7,5)),5,0))
    FROM E1
  UNION ALL
  SELECT C1, C2, MSGCOL,
      CHAR(SUBSTR(MSGCOL, J+6,
                 INTEGER(DECIMAL(VARCHAR(SUBSTR(MSGCOL,J+1,5)),5,0)))),
      I+1,
      J+9+INTEGER(DECIMAL(VARCHAR(SUBSTR(MSGCOL,J+1,5)),5,0))
    FROM IV
    WHERE I < INTEGER(DECIMAL(VARCHAR(SUBSTR(MSGCOL,1,5)),5,0))
 ) SELECT C1, C2, CONSTNAME FROM IV WHERE CONSTNAME = 'constraintname';

To obtain all the Check Constraint violations, one could execute the following:

WITH IV  (C1, C2, MSGCOL, CONSTNAME, CONSTTYPE, I, J) AS
  (SELECT C1, C2, MSGCOL,
       CHAR(SUBSTR(MSGCOL, 12,
                   INTEGER(DECIMAL(VARCHAR(SUBSTR(MSGCOL,7,5)),5,0)))),
       CHAR(SUBSTR(MSGCOL, 6, 1)),
       1,
       15+INTEGER(DECIMAL(VARCHAR(SUBSTR(MSGCOL,7,5)),5,0))
     FROM E1
   UNION ALL
   SELECT C1, C2, MSGCOL,
       CHAR(SUBSTR(MSGCOL, J+6,
                  INTEGER(DECIMAL(VARCHAR(SUBSTR(MSGCOL,J+1,5)),5,0)))),
       CHAR(SUBSTR(MSGCOL, J, 1)),
       I+1,
       J+9+INTEGER(DECIMAL(VARCHAR(SUBSTR(MSGCOL,J+1,5)),5,0))
     FROM IV
     WHERE I < INTEGER(DECIMAL(VARCHAR(SUBSTR(MSGCOL,1,5)),5,0))
 ) SELECT C1, C2, CONSTNAME FROM IV WHERE CONSTTYPE = 'K';