The Alter Table Statement Conflicted With The Foreign Key Constraint

The alter table statement conflicted with the foreign key constraint. All details below.

The alter table statement conflicted with the foreign key constraint

The alter table statement conflicted with the foreign key constraint:

Why does add a foreign key to the tblDomare table result in this error?

The ALTER TABLE statement conflicted with the FOREIGN KEY constraint “FK__tblDomare__PersN__5F7E2DAC”. The conflict occurred in database “almu0004”, table “dbo.tblBana”, column ‘BanNR’.

Code

CREATE TABLE tblDomare
(PersNR VARCHAR (15) NOT NULL,
fNamn VARCHAR (15) NOT NULL,
eNamn VARCHAR (20) NOT NULL,
Erfarenhet VARCHAR (5),
PRIMARY KEY (PersNR));

INSERT INTO tblDomare (PersNR,fNamn,eNamn,Erfarenhet)
Values (6811034679,'Bengt','Carlberg',10);

INSERT INTO tblDomare (PersNR,fNamn,eNamn,Erfarenhet)
Values (7606091347,'Josefin','Backman',4);

INSERT INTO tblDomare (PersNR,fNamn,eNamn,Erfarenhet)
Values (8508284163,'Johanna','Backman',1);

CREATE TABLE tblBana
(BanNR VARCHAR (15) NOT NULL,
PRIMARY KEY (BanNR));

INSERT INTO tblBana (BanNR)
Values (1);

INSERT INTO tblBana (BanNR)
Values (2);

INSERT INTO tblBana (BanNR)
Values (3);

ALTER TABLE tblDomare
ADD FOREIGN KEY (PersNR)
REFERENCES tblBana(BanNR);

It occurred because you tried to create a foreign key from tblDomare.PersNR to tblBana.BanNR but/and the values in tblDomare.PersNR didn’t match with any of the values in tblBana.BanNR. You cannot create a relation which violates referential integrity. https://stackoverflow.com/questions/21839309/the-alter-table-statement-conflicted-with-the-foreign-key-constraint

We have left the transcript of the video below for you:

The alter table statement conflicted with the foreign key constraint. This error is replace table statement which conflicts with foreign key constraint in SQL Server. Consider a scenario where you have two tables you created, you add some data and then your admin asked us if we need to create the foreign key constraint.

Your columns and everything are ready. See here we have the dbo client table and we have the client id. This is a primary key. We have columns for first name, last name, and Social Security number. When you already have this table, you created a dbo order table, order id integer id column.

You have your order item name, order item quantity and customer ID. You also created it. You have now entered the data. You completely forgot to create a foreign key constraint between these two tables. So there is no primary foreign key relationship between the 2 tables. But you went ahead and added some data. Let’s add the data to the dbo customer table. First I add 2 records and you can see it with ID 1 and ID 2 and then we have a first name, last name and social name.

The alter table statement conflicted with the foreign key constraint. We can now also insert the data into the dbo order tables. So we have an order item name, order item quantity, and customer ID. As you can see there are only ID 1 and ID 2 here, but here I am entering ID 1 and 3. It will allow me to add as there is no relation between these two tables like primary K and foreign key relation. It will not validate the data as there is no relationship.
So we’re all fine.

You see, we have customer IDs one and two in the dbo customer table, and then we have one and three in the dbo orders table. Now it suddenly occurred to you, you remember or something you manage, hey you created a foreign key constraint between 2 tables and or you suddenly like to do some data validation and you thought ok, I should create it. The alter table statement conflicted with the foreign key constraint.

Foreign key restriction, but I see some incompatibilities. Ok, here we have id one and two. From where? Why is our ID three? I needed to have a foreign key relationship between 2 tables so they always had to match. Then you checked that and said ok, that’s our problem. We forgot to create the foreign key constraint or the relationship between these two tables now.

The alter table statement conflicted with the foreign key constraint. You go back and change table you say dbo orders constraint foreign key, add customer id foreign key and get customer id from order table references to dbo client which is our primary key table and from there we have client id. Now go ahead and run this and then you got the problem right there. Alter table statement conflicted with foreign key constraint.

The conflict occurred in the database tech siblings and put this and the client id in the table. So why is this happening? Since you have values in dbo orders here, they are not available in the dbo client. So what do you need to do here? You should fix them. Maybe you will say ok I want to fix the values first. This is a way.

You will go ahead and update this customer ID in the order table based on what you have in your dbo customer table. This is one way to do it. Once the records are fixed, you can go ahead and create the foreign key constraint. If your manager doesn’t care, say you consulted the manager, team leader, and business. The alter table statement conflicted with the foreign key constraint.

They say we don’t care about old records. It doesn’t matter, let it go. Let them be as they are. But we want to go ahead and create a forward foreign key constraint and no records should proceed without checking the integrity or verification of the primary key and foreign key.

The alter table statement conflicted with the foreign key constraint. The alter table statement conflicted with the foreign key constraint. You said ok, I can create this constraint that will work forward but it will accept old data no matter what. Even this data is wrong data as primary key and foreign key constraint. But they don’t care because our management or business is fine with old data, we can generate foreign key by ignoring old records. So we will say free of charge. Therefore, do not check the old Oregon current data in the table. Go ahead and create the foreign key constraint, but once the foreign key constraint will be added.

Now added foreign key constraint. Now if you’re going to try to enter any value, let’s say four that don’t exist. You see that we only have one client and client 2 here, and now I’m trying to add 4 here. Sorry control C, if I run this statement it throws an error. It happened. No problem even for old records.

The alter table statement conflicted with the foreign key constraint. Look, there are 3 here, so I’ll say there are still some old phone records or wrong records. But we went ahead and created the restriction using no checker so that it doesn’t check for old data. But advancing any record you add will check using the primary key and foreign key relationship. So if there are no records in the primary key table and you try to enter that value in the foreign key table, it will throw an error. So I hope you learn.

How to use without controller to ignore existing data and continue and create restriction for incoming or future records. So you will be able to create the constraint this way. See you guys in the next video. I will put the link in the description of the scripts so you can copy and play with them. End / The alter table statement conflicted with the foreign key constraint.

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