recoverability

A schedule of three database transactions $T_1, T_2$, and $T_3$ is shown. $R_i(A)$ and $W_i(A)$ denote read and write of data item $A$ by transaction $T_i, i=1,2,3$. The transactio...

Let S be the following schedule of operations of three transactions T 1 , T 2 and T 3 in a relational database system: R 2 (Y), R 1 (X), R 3 (Z), R 1 (Y), W 1 (X), R 2 (Z), W 2 (Y)...

Consider the following database schedule with two transactions, T 1 and T 2 S = r 2 (X); r 1 (X); r 2 (Y); w 1 (X); r 1 (Y); w 2 (X); a 1 ; a 2 where r i (Z) denotes a read operati...

Which of the following scenarios may lead to an irrecoverable error in a database system?