SQL Structured Query Language The Structured Query Language

SQL- Structured Query Language

The Structured Query Language (SQL) Composed of two categories: • Data Definition n create database create table drop database • Data Manipulation n n used to manipulate the data select delete update

Data Definition n n CREATE TABLE - allows you to create a table definition in a database CREATE DATABASE - allows you to create a database DROP TABLE - removes a table from a database ALTER TABLE - modifies the definition of a table in a database

Example 1: Create Table CREATE TABLE CUSTOMER( LAST_NAME varchar 2(30) not null, STATE_CD varchar(2), SALES number); Example 2: CREATE TABLE PRODUCTS( NAME VARCHAR 2(30) NOT NULL, DESCRIPTION VARCHAR 2(300), PRICE NUMBER(4, 2) ) TABLESPACE PRODUCTSPACE STORAGE(INITIAL 25 K NEXT 25 K MINEXTENTS 1);

Alter Table Add column ALTER TABLE CUSTOMER ADD TAX_EXEMPT_ID VARCHAR 2(20); Drop column ALTER TABLE CUSTOMER DROP COLUMN SALES;

Data Manipulation Language n SELECT - query the database • select * from customer where id > 1001 n INSERT - adds new rows to a table. • Insert into customer values (1009, ‘John Doe’) n DELETE - removes a specified row • delete from customer where amount = 100 n UPDATE - modifies an existing row • update customers set amount = 10 where id > 1003

Select n Get all data from table SELECT * FROM TABLE n Get column Distribute data from table SELECT DISTRIBUTE FROM TABLE n Get all data where…. SELECT * FROM TABLE WHERE NAME IS 'BUTCH GREWE'

Insert n Add following entry to table…order of data fields MUST be the same as when created table INSERT INTO TABLE VALUES ('JAMES BOND', '1 EIFFEL TOWER', 'PARIS', 'FRANCE', 'SPY SOFTWARE')

Delete n Remove entries where…. DELETE FROM TABLE WHERE AGE=10

Describe n Get meta-data DESCRIBE TABLE