Database System Concepts - SQL
SQL (Structured Query Language) is THE standard DML for relational database products. The query language is based on relational algebra, but borrows from tuple relational calculus. Topics: • the data-definition language (DDL) - creating, deleting and modifying relation schemas • the data-manipulation language (DML) - the query language • modification of relations (insert, delete, update) • integrity constraints (domain constraints and foreign keys) • creation and use of views • transaction control • application programming Five major standards have been defined for SQL: • SQL-86 • SQL-89 • SQL-92 • SQL:1999 • SQL:2003 Each standard is essentially a superset of the previous ones. Most major commercial systems support essentially the SQL-92 standard along with some part of the SQL:1999 and SQL:2003 standards. In the following examples, we continue to use the flys...
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