serializability

Question

consider the transaction: S:r1(a),r3(d),w1(b),r2(b),w3(b),r4(b),w2(c),r5(c),w4(c),r5(e),w5(b)

1:how many conflict equal serial shedual.

2:how many view equal serial shedual

3:the number of serial order which are view equal but not conflict equal??

Answer 1

I am getting 1 for all the 3 questions.. What's the answer ?

Comments

ans is given 1,2,1 is respectively.

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what are the two orders which are view serializable

Answer 2

The Definition to become view equivalent serial schedule 

1) Initial read must be same.

2)  Any write by Ti  followed by a read in Tj , the same condition should be followed

[ that means We need to preserve Write-Read dependency( W-R ) . ]

3) last operation on some item should be same in view equivalence schedule.

T1 and T5 is fixed , due to initial read and final write .

now T3T4 is in W-R dependency due to w3(b),r4(b) . And T2 is free , T3 always come before T4.

so T1_T3T4_T5  and T2 come in 2 places so number of view equivalent serial schedule is 2 .