I need this pls 100 points pls make your answer long and use 2 details to support ur answer pls i really need this

Err I'm not really sure about this one.

Explanation:

Time 1: Session #1 starts a query on table A

Time 2: Session #2 updates row X in table A

Time 3: The query from session #1 arrives at row X and discovers the last updated time

(based on the SCN number) of the row to be later than Time 1 ... so the UNDO or

LOB segments are used to get the read consistent view (before image) of the row

and then the query proceeds

Time 4: Session #2 updates row Y in table A and then COMMITs (thus making it possible

for this transaction slot to be overwritten)

Time 5: Session #2 updates row Z in table B and COMMITs ... either due to space pressure

(using AUM) or bad luck (using rollback) in the read consistent view for the update

of row Y in table A at time 4 ... is overwritten (we wont examine why the overwrite

occurs at this point)

Time 6: The query from session #1 arrives at row Y and and discovers the last updated time

(based on the SCN number) of the row to be later than Time 1 ... so the UNDO or

LOB segments are examined to find the read consistent view ... BUT ... the

transaction slot containing the view ... was overwritten at time 5 ... so no read

consistent view is available ... so an ORA-1555 occurs

Explanation:

the five different scouting organizations are cub scouts, boy scouts, girl scouts, brownies, and 4h. the main purpose of the scouting movement is to young people develop mentally, spiritually and physically.