SQL Server 2008: The columns in table do not match an existing primary key or unique constraint

Question

I need to make some changes to a SQL Server 2008 database.

This requires the creation of a new table, and inserting a foreign key in the new table that references t

Answer 1

That looks like you are trying to create a foreign key in tblTwo that does not match (or participate) with any primary key or unique index in tblOne.

Check this link on MSDN regarding it. Here you have another link with a practical case.

EDIT:

Answwering to your comment, I understand you mean there are 2 fields in the primary key (which makes it a composite). In SQL it is not possible to have 2 primary keys on the same table.

IMHO, a foreign key field should always refer to a single register in the referenced table (i.e. the whole primary key in your case). That means you need to put both fields of the tblOne primary key in tblTwo before creating the foreign key.

Anyway, I have investigated a bit over the Internet and it seems SQL Server 2008 (as some prior versions and other RDBMS) gives you the possibility to reference only part of the primary key as long as this part is a candidate key (Not Null and Unique) and you create an unique constraint on it.

I am not sure you can use that in your case, but check this link for more information on it.

Answer 2

I have found that the column names must match.

Example: So if tblOne has id called categoryId a reference in tblTwo must also be called categoryId.

_tblname, primary key name, foreign key_
tblOne, "categoryId", none
tblTwo, "exampleId", "categoryId"

I noticed this when trying to create foreign key between 2 tables that both had the column name "id" as primary key.

Answer 3

If nothing helps, then this could be the reason: Considering this case: Table A: Column 1 (Primary Key) Column 2 (Primary Key) Column 3 Column 4

Table B: Column a (Primary Key) Column b Column c

when you are defining a dependency B to A, then you are forced to respect the order in which the primaries are defined.

That's mean your dependency should look like this: Table A Table B Column 1 Column b Column 2 Column c

AND NOT: Table A Table B Column 2 Column c Column 1 Column b

then this will lead to the error you are encountering.

Answer 4

I've had this situation that led me to this topic. Same error but another cause. Maybe it will help someone.

Table1
ColA (PK)
ColB (PK)
ColC


Table2
ID (PK)
ColA
COLB

When trying to create foreign key in Table2 I've choose values from combobox in reverse order

Table1.ColB = Table2.ColB
Table1.ColA = Table2.ColA

This was throwing me an error like in topic name. Creating FK keeping order of columns in Primary key table as they are, made error disappear.

Stupid, but.. :)

Answer 5

I've found another way to get this error. This can also happen if you are trying to make a recursive foreign key (a foreign key to the primary key in the same table) in design view in SQL Management Studio. If you haven't yet saved the table with the primary key it will return this message. Simply save the table then it will allow you to create the foreign key.

Answer 6

This Error happened with me When I tried to add foreign key constraint starting from PrimaryKey Table

Simpy go to other table and and create this foreign key constraint from there (foreign key Table)