Updating a row in db2 iphone updating instructions
Also curious to know if developers in DB2 world use the UR isolation level due to obvious reasons of data integrity compromise and what not. I suspect that it may be useful where you dont care about exact computation and need to compute fast but approximate results (e.g.in cases such as weather forecast etc where results need not be exact - this is just a random example but hopefully you get the idea:)) Many thanx, Same application means the same program running in the same thread.
For example , in a web page with ajax support , you may search a city that starts with ' N' which returns many numbers of rows and are filled in a combo.
The isolation level determines how long read locks are held.
DB2 has the following Isolation levels: RR - Repeatable Read - Holds the share lock on all rows accessed. RS- Read Stability - Hold share lock on all rows accessed. CS - Cursor Stability - Holds share lock on all rows accessed.
The actual data for a lob is stored separately from the rest of the table. So this is because db2 does not support "read consistency" as supported by Oracle, correct?
Thus in the case of db2, if you do a select on a lob and you start updating I guess at that point db2 would lock the row so that others can not update it?
Releases locks when finished accessing a particular row (when DB2 read the next row)..