Warehouse Concepts Interview Question:

Please explain in detail about
type 1,
type 2(SCD),
type 3?

Submitted by: Administrator

Type-1

Most Recent Value

Type-2(full History)

i) Version Number

ii) Flag

iii) Date

Type-3

Current and one Perivies value

SCD'S slow change dimension

there are three types
scd1, scd2, scd3

scd1:- suppose it the data got updated in the table then there r 2 methods one is to drop the table and upload the new one. but its along process.
here by using table compression we can update the particular data that has been modified. that is scd1

scd2:- by using key generation we r going to generate the new rownum column if there r any update the next row will be updated one and row numbers will be increamented automatically by 1

scd3:- i this one a extra column is added and updated infromation is stored in that column. if again table is update another column is added to it again...

in this one scd2 is mostly used..
Submitted by: Administrator