51. What are conflict equivalent schedules?
Ans: Friends Two schedules are said to be conflict equivalent if the order of any two conflicting operations is the same in both schedules.

52. What do you mean by a conflict serializable schedule?
Ans: Friends A schedule is called conflict serializable if it is conflict equivalent to some serial schedule.

53. What do you mean by view equivalence?
Ans: Friends Two schedules S and S’ are said to be view equivalent if the following three conditions hold:
1. Both S and S’ contain same set of transactions with same operations in them.
2. If any read operation read(x) reads a value written by a write operation or the original value of x the same conditions must hold in the other schedule for the same read(x) operation.
3. If an operation write1(y) is the last operation to write the value of y in schedule S then the same operation must be the last operation in schedule S’.

54. What do you mean by view serializable?
Ans: Friends a schedule is said to be view serializable if it is view equivalent with some serial schedule.

55. What are the various methods of controlling concurrency?
Ans: Friends
1. Locking
2. Time stamp
Locking data item to prevent multiple transactions from accessing the item concurrently.
A time stamp is a unique identifier for each transaction, generated by the system.

56. What do you mean by OLTP?
Ans: Friends online transaction processing is an application that involve multiple database accesses
from different parts of the world. OLTP needs a multi-user DATABASE MANAGEMENT SYSTEM software to ensure that concurrent
transactions operate correctly.

57. What do you mean by a lock?
Ans: Friends a lock is a variable associated with a data item that describes the status of the item with respect to the possible operations that can be applied to it.

58. What are various types of locking techniques?
Ans: Friends
1. a binary lock
2. Shared/Exclusive lock
3. Two phase locking

59. What do you mean by a binary lock?
Ans: Friends A binary lock can have two states or values:
1. locked (1)
2. Unlocked (0)
If locked it cannot be accessed by any other operations, else can be.

60. What do you mean by shared or exclusive lock?
Ans: Friends It implements multiple-mode lock. Allowing multiple accesses for read operations but exclusive access for write operation.