Microsoft Access Help please??

Please can you help me im trying to list my products onto a database using microsoft access but now i have realised that a lot of my reference numbers are duplicated!!

Is there a way that access will either inform me that a ref number in that column is already there and that it would be duplicated otherwise???

Or how can I stop this field/column from duplicating as it would save me loads of time if i didnt need to keep putting them in twice and then realising that they have been duplicated and then I have to spend time removing them!!! Thankyou!!!

Microsoft Access Help please??microsoft

To make prevent reference number field from duplicating is to make it a unique field.

To remove the duplicate entries, the easiest way is to do the following.

First, make sure you backup the database.

Open the table and sort the reference number column in ascending/descending order. You can proceed to select the duplicate reference number and delete.

Don't forget to backup the database before making changes to a live database.

Microsoft Access Help please??norton ghost

In design view Change the indexed properties in the table from the general tab to Yes (No Duplicates)
Set the field as a unique or primary key.
In the Design View of the table, there is a list of properties for each of the fields you have created. Change the 'Indexed' property to "Yes (No Duplicates)". Before doing this, you will have to make sure that there are no duplicates in that field otherwise it will not allow you to make the change.
The problem with Access is it will duplicate you will have to override it it should be in your help on the program for you to override or your going to have to change them manually
simply do a

select RefNumber, Count(refNumber) from Yourtable

Group By Refnumber

having count(refnumber)%26gt;1

Once you have your list of duplicated number you can cahnge them , then once you have run the above statement and received 0 records you can go ahead and a apply a primary key index to the table which does not allow duplicates.

ok?