The ALTER TABLE statement conflicted with the FOREIGN KEY constraint

How to Fix the "The ALTER TABLE statement conflicted with the FOREIGN KEY constraint" Error in SQL

So you're trying to add a foreign key to the tblDomare table, but it's throwing this error at you: "The ALTER TABLE statement conflicted with the FOREIGN KEY constraint 'FK__tblDomare__PersNR__5F7E2DAC'. The conflict occurred in database 'almu0004', table 'dbo.tblBana', column 'BanNR'."

🤔 What does this error mean and how can you fix it? Don't worry, we've got you covered! In this guide, we'll break down the issue, provide easy solutions, and even give you a cool call-to-action at the end.

Understanding the Error

Let's start by understanding what this error message is trying to tell us. Essentially, it's saying that the FOREIGN KEY constraint you're trying to add to the tblDomare table is conflicting with existing data in the tblBana table.

In simple terms, the foreign key you're trying to add references a value in tblBana that doesn't exist. This is because the value you're referencing in tblBana's BanNR column is not present.

Finding the Culprit

To identify which specific data is causing the conflict, take a closer look at the values you inserted into the tblDomare and tblBana tables.

In this example, the tblBana table has three values in the BanNR column: 1, 2, and 3. However, the values you inserted in the tblDomare table's PersNR column (6811034679, 7606091347, and 8508284163) do not match any of the values in tblBana.

Fixing the Error

Now that you understand the problem, it's time to fix it. Here are a couple of solutions:

Solution 1: Add the missing values to tblBana

If the values in tblDomare's PersNR column are valid references to tblBana's BanNR column, you should add those missing values to the tblBana table. In this case, you would need to insert the values 6811034679, 7606091347, and 8508284163 into tblBana's BanNR column.

INSERT INTO tblBana (BanNR)
VALUES (6811034679);

INSERT INTO tblBana (BanNR)
VALUES (7606091347);

INSERT INTO tblBana (BanNR)
VALUES (8508284163);

After inserting the missing values, you can then proceed to add the foreign key without encountering any conflicts.

Solution 2: Update the values in tblDomare

If the values in tblDomare's PersNR column are not intended to be foreign keys referencing tblBana's BanNR column, you should update those values to valid references or remove the foreign key constraint altogether.

For example, if the PersNR column should match the BanNR column in tblBana, you would update the tblDomare table as follows:

UPDATE tblDomare
SET PersNR = '1'
WHERE PersNR = '6811034679';

UPDATE tblDomare
SET PersNR = '2'
WHERE PersNR = '7606091347';

UPDATE tblDomare
SET PersNR = '3'
WHERE PersNR = '8508284163';

After updating the values in tblDomare, you can then add the foreign key constraint without any conflicts.

Conclusion

Congratulations! You've now fixed the "The ALTER TABLE statement conflicted with the FOREIGN KEY constraint" error in SQL. Whether you added the missing values to tblBana or updated the values in tblDomare, you're no longer encountering conflicts when adding the foreign key.

If you found this guide helpful, make sure to share it with your fellow SQL enthusiasts. And if you have any other SQL queries or tech questions, feel free to reach out and engage with us. We're always here to help! 😊🚀