Relational databases and OO languages

Question

In a typical ASP.NET web application architecture, we are using a OO language such as C# and a relational database such as SQL server for data.

I was reading a book on Linq that said "The problem is there is a gap between a OO programming language and a relational database"

What exactly is the author trying to imply?

EDIT: Thanks for the answers. I am not sure I understand how LINQ would solve this problem. I might be wrong but it appears that LINQ is API for database communication just like ADO.NET

Answer 1

They are very different data models and ways of doing things. It's quite a religious argument with no quarter given and no mercy expected.

It's all here: Object-relational impedance mismatch