Subject Low Selective Index
Author chee hee
Hi All,

I have a transaction table which has about 5 million records (and growing) and has a foreign key column to a table called Company. The Company table only has 3 records. I understand that a foreign key will have an index created automatically. So this would be a very low selective index and from the book theory, low selective index is not good for performance.

So in general, should we create foreign key from very huge table (> million records) to very small table (< 10 records) ?

Thanks in advance.


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