Question

I have multiple content types, but they all share some similarities. I’m wondering when it is a problem to use the same table for a different content type? Is it ever a problem? If so, why?

Here’s an example: I have five kinds of content, and they all have a title. So, can’t I just use a ‘title’ table for all five content types?

Extending that example: a title is technically a name. People and places have names. Would it be bad to put all of my content titles, people names, and place names in a “name” table? Why separate into place_name, person_name, content_title?

I have different kinds of content. In the database, they seem very similar, but the application uses the content in different ways, producing different outputs. Do I need a new table for each content type because it has a different result with different kinds of dependencies, or should I just allow null values?

Answer 1

While normalization is a very good practice to avoid redundency and ensure consistency, it can be bad for performance sometimes. For example for a person table where you have columns like name, adress, dob its not very good performance wise to have a picture in the same table. A picture can be about 1MB easily while the remaining columns may not take any more than 1K. Imagine how many blokcs of data needed to be read even if you only want to list the name and address of people living in a certain city – if you are keeping everything in the same table.

If there is a variation in size of the contents and you might have to retrieve only certain types of contents in the same query, the performance gain from storing them in separate tables will outweight the normalization easily.