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Update by cursor

 
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danm
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Joined: 29 Jun 2004
Posts: 170
Topics: 73
PostPosted: Thu Jan 26, 2006 4:26 pm    Post subject: Update by cursor Reply with quote
I can use "WHERE CURRENT of Cursor_Name" when rows are selected form a single table. It wouldn't work if the FROM clause of the SELECT statement contains more than one table. But I need join another table to get the "Status" to determine if update should be applied. Is there a work around?
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kolusu
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Joined: 26 Nov 2002
Posts: 12378
Topics: 75
Location: San Jose
PostPosted: Fri Jan 27, 2006 6:04 am    Post subject: Reply with quote
danm,

Get the status using a Subquery and use where CURRENT of clause.

Kolusu
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danm
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Joined: 29 Jun 2004
Posts: 170
Topics: 73
PostPosted: Mon Jan 30, 2006 8:58 am    Post subject: Reply with quote
kolusu,

This is what I want to accomplish:
Code:

"DECLARE SELCUR CURSOR FOR",
  "SELECT A.COL1, A.COL2, A.COL3, B.STATUS",
  "FROM TABLE A, TABLE B",
  "WHERE A.KEY1 = B.KEY1 AND A.KEY2 = B.KEY2 AND A.KEY3 = B.KEY3",
  "AND B.STATUS IN ('X','Y')",
  "FOR UPDATE OF COL1, COL2, COL3"
"OPEN SELCUR"
Do until SqlCode = 100
  "FETCH SELCUR INTO :DATA1, :DATA2, :DATA3, :STATUS"
  "UPDATE TABLEA SET COL1 = :NEWDATA1, COL2 = :NEWDATA2, COL3 = :NEWDATA3",
  "WHERE CURRENT OF SELCUR"
  /* Insert rows into table c only if stauts = 'Y' */
  If Stauts = 'Y' then "INSERT INTO TABLEC VALUES (:DATA1, :NEWDATA1,.....)
End


How do I replace the join tables by a subquery?
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kolusu
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Joined: 26 Nov 2002
Posts: 12378
Topics: 75
Location: San Jose
PostPosted: Mon Jan 30, 2006 10:45 am    Post subject: Reply with quote
danm,

huh, I am confused. you are selecting col1, col2, col3 from table A and updating them with the same values?

Kolusu
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danm
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Joined: 29 Jun 2004
Posts: 170
Topics: 73
PostPosted: Mon Jan 30, 2006 11:42 am    Post subject: Reply with quote
kolusu,

No, I fetch Col1, Col2 and Col3 to Data1, Data2 and Data3, then update col1, col2 and col3 with NewData1, NewData2 and NewData3.

The followoing subquery works with "FOR UPDATE" clause:

Code:

"DECLARE SELCUR CURSOR FOR",
  "SELECT COL1, COL2, COL3",
  "FROM TABLEA A",
  "WHERE (KYE1, KEY2, KEY3)",
  "   IN ((SELECT KEY1, KEY2, KEY3", 
  "        FROM TABLEB",
  "        WHERE STATUS = 'X'",
  "        AND A.KEY1 = KEY1 AND A.KEY2 = KEY2", 
  "        AND A.KEY3 = KEY3))",
  "FOR UPDATE OF COL1, COL2, COL3"     


But I need to run the query twice, first time with STATUS = 'X' and the second time with STATUS = 'Y'. Looking for a way to run the query only once.
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