what is Primary key and unique key and what is the
Difference?
Answers were Sorted based on User's Feedback
Answer / mahender achhe
Primary key does not allow the null values but where as in
unique key accepts the null values.
Is This Answer Correct ? | 16 Yes | 3 No |
Answer / andsens
Fields in UNIQUE CONSTRAINTs can be NULL. They cannot with PRIMARY KEYs.
You can define more than one UNIQUE KEY in a table.
Because of this, the behaviour of UNIQUE CONSTRAINTs
is very different from PRIMARY KEY constraints.
As long as one of the fields in a UNIQUE CONSTRAINT is NULL
the constraint itself does not apply and you can set the other fields
to whatever you want without getting an error.
Is This Answer Correct ? | 5 Yes | 0 No |
ABOVE ITS WRONG FOR UNIQUE KEY, SORRY.
UNIQUE KEY REFERS TO THE NON-NUMERIC KEY .
Is This Answer Correct ? | 8 Yes | 4 No |
PRIMARY KEY IS A FIELD WHICH IS USED TO IDENTIFY THE TABLE
AND THESE CANNOT BE CHANGED, IF IT IS CHANGED THE DATA
INTEGRITY WILL GET LOST.
UNIQUE KEY IS A GROUP OR A SINGLE FIELD WHICH IS USED TO
REPRESENT THE NUMERIC FIELDS WHICH DOESNT CHANGE.
THE GROUP OF NUMERIC FIELDS IS THE UNIQUE KEY.
PRIMARY KEY IS USED FOR DATABASE TABLES WHERE AS UNIQUE KEY
IS USED FOR INTERNAL TABLES.
Is This Answer Correct ? | 4 Yes | 13 No |
If i work in an implementation project will i have to register with SAP?What is the process of blue printing?What is the role of an abapper in implementatin project? Regards,
Among pooled and Cluster tables, in which table data used to store in Row Format?
What is the difference between Initialization and parameters ?
In module pool program how to pass the one screen input value to another screen input value?
How do you find if a logical database exists for your program requrements?
In one of our zflash against collections report is not matching with the actual collections i.e invoice valuse of 200000 and payment had received for entire invoice and as per accounts of the particular customer this invoice is cleared but when we had tken z flash for collections which had developed my ABAP tem it's not matching.it's happened for many invoices how to get right report as per the payment details?
what are the conversion routine?
What is binary search? where it is used?
what is the diffreence between sap memory and abap memory plz give the example
what is Work flow?
What is the master data necessary before you can start posting in MM?
how to creat a table with out primary key