I know that i can create a table without a primary key.But
is there any significance for that table???? while creating
an application.
Answer Posted / amit
Definitely yes.....While creating a Data Warehouse
application,we need fact tables to be created from various
dimension tables and the fact table load type is always
INSERT not INSERT/UPDATE.Just think of a real world example
where the need is to populate all the daily transactional
data to a Data Warehouse for analytical purpose such as
creating reports and all.Suppose the DW is loaded two times
a day.In the first load,whatever the data present in the
Transactional Database is loaded into the DW.Before the
second load there might be some sort of updation made to
some of the records,so those records need to be inserted
into the DW again in the second load.If there would be
primary key in the fact table(i,e;DW),it will raise an error
(unique constraint violated.....).So,fact tables should not
contain any primary key.
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