What is a surrogate key?Why we use it in a mapping?Pl give
an example.
Answer Posted / saradhi
surrogate key is used to avoid the critical column.critical
column means the column which makes the analysation or data
wrong for example assume one customer table
cust_id(p.k) cust_name amount loc
1 jones 1000 hyd
he purchase the product in hyd by 1000/- if he again
purchase by 2000/- in pune not in hyd.then we have to
create another record in that table with same cust_id but
here cust_id is having primary key so we are unable to
create a new record for suppose if u update the record u
got the wrong information as
1 jones 3000 pune
so eliminating this we are maintian the another column like
cust_no as surrogate key (unique value)and removes p.k in
cust_id.surrogate key is like an index.
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