In today’s post, we will examine what “The changes you requested to the table were not successful because they would create duplicate values” error means, what causes it, and practical approaches to resolving it.
The capability of any database to index each record uniquely makes it possible for users to modify records. However, if you come across a response showing the above error, you cannot use your data records unless you address the issue.
What this error means
As the error response suggests, it occurs when putting a new record onto a table with AutoNumber indexing. It’s also common in cases where the seeding of the indexing field wasn’t done properly. This makes the AutoNumber field to assign invalid values to your newly-created records. Therefore, you cannot incorporate additional records into your database and this renders it useless for future transactions.
What could be responsible for this error?
Various reasons can cause the above error as discussed below.
1. Bugs in the JET Database Engine
The JET database engine is useful in manipulating and managing a relational database. It’s tasked with ensuring data integrity and transaction processing, among other things. To ensure this happens, all transactions must be unique, something achieved by sequential indexing of the primary key in a database table.
If the JET engine can’t guarantee unique indexing of records, then problems are sure to happen. For instance, a bug in the fourth version of the Microsoft JET database engine is commonly known to cause faults in seeding the AutoNumber field in most database tables. To avoid this, it’s advisable to have a JET service pack that’s up to date.
2. Poor database design
Poor design may be among the greatest impedance to the proper functioning of a database. Some design flaws able to trigger the error above include linking subform and main form to a table such that both can either alter the AutoNumber field. This means entries in both the subform and main form are captured as new records on the table. Also, if you set the AutoNumber as a random value, there is the potential of replicating records.
3. Database corruption
Another common cause of the above error is Access database corruption. A myriad of issues such as software conflict, corrupt computer registry, a sudden power outage, or computer viruses can cause database corruption.
What to do when you face this error
To fix this problem permanently, you will need to perform an accurate diagnosis of the root cause. Start by analyzing the history of your database to help you unearth any underlying issues. For instance, if your database is relatively new and you have not performed a thorough error testing, then there’s a chance that the cause is a design issue and not necessarily data corruption. In this case, investigate your form designs and ensure that the AutoNumber fields have “New Records” and “Field Size” are set to “Increment” and “Long Integer”, respectively.
On the flip side, if your database had been operational for a long time and then issues showed up after the update of the JET database engine, consider MS Access’s compact and repair function to reset the AutoNumber seeding in your database. Now, install a stable version of the JET engine on your computer. This should fix the problem.
If you are dealing with a corrupt database, use the DataNumen Access Repair software to recover your files. Now, come up with a new database and give it a different name. You may move the restored files to the newly-created database. You now have your database up and running.