This chapter revisits conceptual database design and focuses on the so-called “logical database tuning”. We first recall fundamental differences between constructor-oriented models (like extended Entity-Relationship models) and attribute-oriented models (like the relational model). Then, we introduce an integrated algorithm for translating ER-like conceptual database schemas to relational database schemas. To consider the tuning of such logical databases, we highlight two extreme cases: null-free databases and efficient — though non redundant — databases. Finally, we point out how SQL workloads could be used a posteriori as a help for the designers and/or the database administrators to reach a compromise between these extreme cases. While a lot of papers and books have been devoted for many years to database design, we hope that this chapter will clarify the understanding of database designers when implementing their databases and database administrators when maintaining their databases.