Tóm tắt

In 1970, an IBM researcher named Ted Codd published the first article on relational databases. Itoutlined an approach that used relational calculus and algebra to allow non-technical users to storeand retrieve large amounts of information. Codd envisaged a system where the user would be able toaccess information stored in tables with natural language commands. The article's significance was not recognised because it was far too technical and relied heavilyon mathematics. However, it did lead to IBM starting a research group known as System R.Eventually, System R evolved into SQL/DS which later became DB2. The language created by the System R group, SQL (Structured Query Language) has become the industry standard for relational databases and is now an ISO standard.The first database systems built upon the SQL standard appeared at the beginning of the 1980sfrom Oracle with Oracle Version 2, and later SQL/DS from IBM, as well as a host of other systems from other companies. Relational database technology was continually refined during the 1980s. This was due to feedback from customers, the development of systems for new industries and the increased use of personal computers and distributed systems.