multi user Flashcards
1
Q
3 possible error of multi user database
A
lost update
dependency of not free changes
phantomproblem
2
Q
explain lost update
A
2 user updated data at the same time thus one lost one updated
3
Q
explain dependency on uncommited update
A
next transaction depends on not yet commited
4
Q
serialisierung
A
it refers to the ability of the dbms to control the execution of concurent transactions that the end result =serial execution
-tracks history
-> ensure consistent result
5
Q
operations of a transaction (T)
A
w(x)
r(x)
a(x)
c(x)
6
Q
reasons to prevent not serial
A
data inconsistency
unpredctibility
trouble shooting
7
Q
A
