Jennifer Widom

SQL

Introduction

Jennifer Widom

SQL: Intro

“S.Q.L.” or “sequel” Supported by all major commercial database systems Standardized – many new features over time Interactive via GUI or prompt, or embedded in programs Declarative, based on relational algebra

Jennifer Widom

Data Definition Language (DDL)

Data Manipulation Language (DML)

Other Commands indexes, constraints, views, triggers, transactions, authorization, …

SQL: Intro

Jennifer Widom

The Basic SELECT Statement

Select A1,A2,…,An

From R1,R2, …,Rm

Where condition

SQL: Intro

Jennifer Widom

SQL: Intro

“S.Q.L.” or “sequel” Supported by all major commercial database systems Standardized – many new features over time Interactive via GUI or prompt, or embedded in programs Declarative, based on relational algebra