I have a page where people can enter in first/last name, phone, email, and ethnicity click add and it adds an entry into the datatables. The problem is after clicking add th
As you can see in this fiddle your code is correct and should work as expected.
In any case to set a row height, simply use css
tr { height: 50px }
i think there is no need for it to be more complex.
Regarding the question on how to insert the data into a db, there are tons of examples on google.