what is surrogatekey ? In ur project in which situation u
has used ? explain with example ?
Answer Posted / murali
the surrogate key is the primary key used to avoid the
problem of critical column. let me clarify u with example...
table A:
Cust_no(PK) Cust_name Loc
100 X Mumbai
this is what ur OLAP DHW is having abt Customer X
But, he has changed his address from X to Y. U have to
update this in ur OLAP DWH. then, i u try to insert this
into ur Table A,
Error: Prinary key Constraint violated (Coz,PK is same for
the both the records)... then, LOC is the Critical Column.
to avoid this, we need to generate a primary key either by
user defined or system generated.
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