ACID Properties in RDBMS | Atomicity | Consistency | Isolation | Durability

            
           For Video Explanation please watch my you tube video:


                  


For Class notes please see below:
ACID :

Atomicity:

Either all or None

T1  transfer 5000 from account a to account b
read(a)  -op1
a=a-5000 - op2
write(a) -op3
read(b)
b=b+5000
write(b)- system crashed, power goes,techinical or non technical
commit;


Consistency
T1  transfer 5000 from account a to account b

total money before the starting of the transaction must be equal to total
money after the trasaction take place.
before transaction
A  - 2000
B  - 3000
T1 need to trasfer 1000 rupees from A to B

After transaction:
A - 1000
B - 4000


Isolation:

T1    T2

parallel transactions

T1  transfer 1000 rupees from A to B 
T2  transfer 2000 rupees from B to C

T1 
T2

Durability:
T1 transfer 1000 rupees from A to B 
read(a)  -op1
a=a-5000 -op2
write(a) -op3
read(b)  -op4
b=b+5000 -op5
write(b) -op6
commit;  -op7

A = 1000
B = 4000


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