How to convert pl/sql block into single update statement

Question

Dear all gurus,
I have pl/sql block mention below, Can I convert this pl/sql block to single update statement if possible?
If not how to optimize this block?
Pleaese suggest.
thanks in advance.
Vijay
DECLARE
CURSOR vt_mlr_cursor IS Select master_key, user4 from vt_mlr Where USER4 is not null;
USERFIELD VARCHAR2(100);
C1 VARCHAR2(3); /* this will return location of first space = 12 */
C2 VARCHAR2(3); /* this will return location of second space = 20 */
C3 VARCHAR2(3); /* this will return location of third space = 28 */
C4 VARCHAR2(3); /* this will return location of forth space = 35 */
Field1 VARCHAR2(40); /* this will return FTMYFLXA04W */
Field2 VARCHAR2(10); /* this will return VPI0043 */
Field3 VARCHAR2(10); /* this will return VCI0184 */
Field4 VARCHAR2(10); /* this will return 005 */
Field5 VARCHAR2(10); /* this will return 00001 */
Field_2_n_3 VARCHAR2(25);
key VARCHAR2(10);
BEGIN
FOR vt_mlr_record IN vt_mlr_cursor
LOOP
key := vt_mlr_record.master_key;
USERFIELD := vt_mlr_record.user4;
C1 := INSTR(vt_mlr_record.user4,' ',1,1); /* this will return location of first space = 12 */
C2 := INSTR(vt_mlr_record.user4,' ',1,2); /* this will return location of second space = 20 */
C3 := INSTR(vt_mlr_record.user4,' ',1,3); /* this will return location of third space = 28 */
C4 := INSTR(vt_mlr_record.user4,' ',1,4); /* this will return location of forth space = 35 */
Field1 := SUBSTR(vt_mlr_record.user4,1,C1-1); /* this will return FTMYFLXA04W */
Field2 := SUBSTR(vt_mlr_record.user4,C1+4,C2-C1-4); /* this will return VPI0043 */
Field3 := SUBSTR(vt_mlr_record.user4,C2+4,C3-C2-4); /* this will return VCI0184 */
Field4 := SUBSTR(vt_mlr_record.user4,C3+4,C4-C3-4); /* this will return 005 */
Field5 := SUBSTR(vt_mlr_record.user4,C4+4,LENGTH(vt_mlr_record.user4)-C4-3); /* this will return 00001 */
Field_2_n_3 := Field2 || '/' || Field3;
/*DBMS_OUTPUT.PUT_LINE ('Current key is: ' || vt_mlr_record.master_key);*/
UPDATE vt_mlr
SET
aggregator_clli = Field1,
aggregator_vpi_vci = Field_2_n_3,
aggregator_slot = Field4,
aggregator_port = Field5
WHERE
master_key = vt_mlr_record.master_key;
END LOOP;
END;
/

Answer 1

Hi Vijay,
Here's something to start with, you should be able to complete it.
First, combine your select and update statements:
update vt_mlr
   set aggregator_clli = field1
      ,aggregator_vpi_vci = field_2_n_3
      ,aggregator_slot = field4
      ,aggregator_port = field5
where user4 is not null;Then put these two
C1 := INSTR(vt_mlr_record.user4,' ',1,1); 
Field1 := SUBSTR(vt_mlr_record.user4,1,C1-1);into
Field1 := SUBSTR(vt_mlr_record.user4,1,INSTR(vt_mlr_record.user4,' ',1,1) -1);And put it into the update statement, removing reference to record
(I have also removed default values for position and occurrence in instr function):
update vt_mlr
   set aggregator_clli = substr(user4, 1, instr(user4,' ') - 1)
      ,aggregator_vpi_vci = field_2_n_3
      ,aggregator_slot = field4
      ,aggregator_port = field5
where user4 is not null; I think you can do the rest from here ;-)
Regards
Peter