Relational Model - Keys in SQL | Database Tutorial 2f

In this lecture of the databases course we learn about keys, composite keys and minimal keys in SQL and the relational database model. A key is a set of attributes whose values uniquely identify the row of the table (relation). Keys should never be updated as they are used as an address to reference rows of a table.

This is the databases online course given at the Vrije Universiteit Amsterdam by Jörg Endrullis. The course objective is to obtain a good understanding of relational database systems from the user perspective. This includes the ability to develop conceptual database models, as well as key concepts and skills in relational database theory and practice.

Among others, we treat in this course the following subjects:
(a) entity–relationship diagrams for the design of database schemata,
(b) the relational database model and integrity constraints,
(c) SQL (structured query language) for retrieving information from relational databases,
(d) database normalisation and functiona dependencies (reasoning about good database design),
(e) transactions and concurrency control.

The slides are based on work by Peter Boncz and Torsten Grust.