SQL Server primary / foreign keys

Question

I am developing a system in which I have a table Employees with multiple columns related to employees. I have a column for the JobTitle and another column for Department .

In my current design, the JobTitle & the Department columns are compound foreign keys in the Employees table and they are linked with the Groups table which has 2 columns compound primary key ( JobTitle & Department ) and an extra column for the job description.

I am not happy about this design because I think that linking 2 tables using 2 compound varchar columns is not good for the performance, and I think it would be better to have an Integer column (autonumber) JobTitleID used as the primary key in the Groups table and as a foreign key in the Employees table instead of the the textual JobTitle & the Department columns.

But I had to do this because when I import the employees list (Excel) into my Employees table it can just be directly mapped (JobTitle --> JobTitle & Department --> Department). Otherwise if I am using an integer index as primary key I would have then to manually rename the textual JobTitle column in the excel sheet to a number based on the generated keys from the Groups table in order to import.

Is it fine to keep my database design like this (textual compound primary key linked with textual compound foreign key)? If not, then if I used an integer column in the Groups table as primary key and the same as a foreign key in the Employees table then how can I import the employees list from excel directly to Employees table?

Is it possible to import the list from Excel to SQL Server in a way that the textual JobTitle from the excel sheet will be automatically translated to the corespondent JobTitleID from the Groups table? This would be the best solution, I can then add JobTitleID column in the Groups table as a primary key and as a foreign key in the Employees table.

Thank you,

Answer 1

It sounds like you are trying to make the database table design fit the import of the excel file which is not such a good idea. Forget the excel file and design your db tables first with correct primary keys and relationships. This means either int, bigint or guids for primary keys. This will keep you out of trouble unless you absolutely know the key is unique such as in a SSN. The when you import, then populate the departments and job titles into their respective tables creating their primary keys. Now that they are populated, add those keys to the excel file that can be imported into the employees table.

This is just an example of how I would solve this problem. It is not wrong to use multiple columns as the key but it will definitely keep you out of harms way if you stick with int, bigint or guids for your primary keys.

Answer 2

Look at the answer in this post: how-to-use-bulk-insert...

I would create a simple Stored Procedure that imports your excel data into a temporary unrestricted STAGING table and then do the INSERT into your real table by doing the corresponding table joins to get the right foreign keys and dump the rows that failed to import into an IMPORT FAIL table. Just some thoughts...