Updating sql tables when joined 2016 online dating sites in dubai
We often use join clauses to query rows in a table that have (in the case of INNER JOIN) or may not have (in the case of LEFT JOIN) corresponding rows in another table.
Doing a 'join update' in Oracle can sometime cause a few headaches.
This update will fail if s.new_value is not unique. OLD_VALUE) * ERROR at line 3: ORA-38104: Columns referenced in the ON Clause cannot be updated: "T"."VALUE" here iam updating value with new_value. OLD_VALUE) * ERROR at line 3: ORA-38104: Columns referenced in the ON Clause cannot be updated: "T"."VALUE" November 29, 2007 - am UTC well, it is what is says it is you cannot modify the join columns in a merge, it is against the rules. you could use a global temporary table with a primary key on the join column, insert the data from S into this table where fld='a' and then update the join. Iam asking this because oracle allows UPDATE statement to do that but not the merge.
..." not true: (to continue your last example): insert into s values('B', 3, 8); insert into s values('B', 4, 8); select * from s; F OLD_VALUE NEW_VALUE - ---------- ---------- A 1 5 A 2 6 A 3 7 B 3 8 B 4 8 UPDATE T SET VALUE = (SELECT NEW_VALUE FROM S WHERE VALUE = OLD_VALUE AND FLD = 'A') MERGE INTO T 2 USING (SELECT * FROM S WHERE FLD = 'A') S 3 ON (T. OLD_VALUE) 4 WHEN MATCHED THEN 5 UPDATE SET VALUE = S. There should not be any problem but it still not allowing me. So just curious to know what stops oracle for allowing it.(remember, merge IN GENERAL can insert, update and delete from the TGT)... do we update the TGT row twice - from 5 to 6, then 6 to 7 do we update the TGT row once and insert a duplicate ID? Attribute ID AND 6 CASE WHEN LOWER(s.value) = LOWER(p.value) THEN 1 ELSE 2 END = 2 7 ) 8 WHEN MATCHED THEN 9 UPDATE SET p. Value; CASE WHEN LOWER(s.value) = LOWER(p.value) THEN 1 ELSE 2 END = 2 * ERROR at line 6: ORA-38104: Columns referenced in the ON Clause cannot be updated: "P"."VALUE" SQL MERGE INTO p 2 USING s 3 ON ( 4 p.
This is known as a 'spill' and it can be a very slow operation.
This promotes sequential access to the table, which is often much more efficient than random access.