DBMS Interface – SQL
Paul Beynon‐Davies · 1996
In this chapter we shall reflect the relational data model (chapter 3) against the contemporary practice of relational database systems. Contemporary practice is primarily centred around a language known as SQL (Structured Query Language). SQL was originally designed as a query language based on the relational calculus (section 3.3.11). The current specification of SQL is however much more than simply a query language. It is more accurately described as being a database sublanguage. Indeed, this database sub-language is becoming the standard interface to relational and non-relational DBMS.