Databases Course - Relational Model - Foreign Keys in SQL | Database Tutorial 2g

In this lecture of the databases course we learn about foreign keys in SQL and the relational database model. To refer from a table A to rows of table B, we can include the (primary) key attributes of B in A. So we include the "address" of rows in B in the table A. This address is called for foreign key. The database management system (DBMS) must ensure that the rows that are referenced by these addresses indeed exist. This is called referential integrity and is ensured by declaring a foreign key constraint. 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.