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.

Is This Answer Correct ?    0 Yes 0 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

How to write an inner join with the where clause in oracle?

824


How to convert a string to a date in oracle database?

804


What is the difference between I and G in Oracle?

820


How to save query output to a local file?

805


Difference between oracle's plus (+) notation and ansi join notation?

859


What is recovery manager(rman) backup in Oracle?

917


What is raw datatype in oracle?

831


How to connect to a remote server?

798


State and explain about oracle instance?

763


Explain the use of record option in exp command.

770


What are the different types of trigger and explain its various uses and functions?

756


When do I need to use a semicolon vs a slash in oracle sql?

826


What privilege is needed for a user to query tables in another schema?

752


Can you drop an index associated with a unique or primary key constraint?

799


What are the differences between primary key and unique key?

751