Greetings,

While studying code for some minor issue, I came across this select statement in a java script. This has surprised me, It does not seem to use a cursor.

I tend to believe that I may not know, or I may have not used select this way.

Can some one help me understand why FOR UPDATE OF was used in this statement ?

SELECT * FROM Client_Acc WHERE Acc_Num = ? FOR UPDATE OF Cash_Amt,Real_Chips,Promo_Chips

Help is appreciated. (searched online , all belong to cursor def).

Regards

DBFinder

That is used to obtain an IX (intent exclusive) lock on the row which means that no one else can obtain another IX lock, nor an X lock, but others can get a S (share) lock. The lock is released when a commit or rollback is issued.

see doc
Select-statement

Thanks


DBFinder

That doc does not tell the whole story. FOR UPDATE can be used without a cursor and is often used to obtain a lock as I described above (while the application examines the contents of row in a select and does not want any others to update it, but want others to be able to read it).

Also, it can be used for a positioned DELETE (in addition to UPDATE).

or if you have problems with locking - look at optimistic locking in the doc..