INTRODUCTION TO SQLDAT702

Standard Query Language Ability to access and manipulate databases

◦ Retrieve data◦ Insert, delete, update records◦ Create and set permissions

databases, tables, procedures and views◦ Query databases

WHAT IS SQL

ULI101◦ HTML◦ Create a webpage

INT213◦ ASP◦ Connect to database to make webpage functional

DAT702 ◦ SQL◦ Manipulate data in database connected to

webpage

BUILDS ON PREVIOUS COURSES

Relational Database Management System◦ SQL, MS Access, Oracle, IBM DB2, SQL Server

Data is stored in database objects called tables

A table is a collection of related data organized into columns (fields) and rows (records)

RDBMS

Defined by SQL Many are mandatory, but most are optional

SELECT name FROM teams WHERE id = 9

SELECT and FROM are mandatory WHERE is optional

KEYWORDS

Names that are given to database objects such as tables and columns

“teams” is the table name “name” and “id” are column names

IDENTIFIERS

SELECT name FROM teams WHERE id = 9

Literals that represent fixed values

“9” is a numeric constant

CONSTANTS

SELECT name FROM teams WHERE id = 9

A portion of an SQL statement

The SELECT clause is “SELECT from” The FROM clause is “FROM teams” The WHERE clause is “WHERE id = 9”

CLAUSES

How the clause is put together

What keywords, identifiers and constants does it consist of

MOST IMPORTANTLY – are they in the correct order according to SQL

SYNTAX

Used to manage database objects such as tables and columns

CREATE, ALTER and DROP

mysql> create table teams (id int(5) not null primary key, name varchar(37) not null, division varchar(2)); Query OK, 0 rows affected (0.05 sec)

DDL COMMANDS

mysql> create table teams (id int(5) not null primary key, name varchar(37) not null, division varchar(2)); Query OK, 0 rows affected (0.05 sec)

CREATE

+------------+-------------+-----+------+---------+-------+ | Field | Type | Null | Key | Default | Extra |+------------+-------------+-----+------+---------+-------+ | id | int(5) | NO | PRI | NULL | | | name | varchar(37) | NO | | NULL | | | division | varchar(3) | YES | | NULL | |+------------+-------------+-----+------+---------+-------+3 rows in set (0.00 sec)

mysql> ALTER TABLE teams DROP COLUMN division;

Query OK, 0 rows affected (0.15 sec)Records: 0 Duplicates: 0 Warnings: 0

Check to make sure the column no longer exists

ALTER

mysql> DROP TABLE teams;Query OK, 0 rows affected (0.03 sec)

Check to make surethe table no longer exists

DROP

Used to manage data within tables and columns

INSERT, UPDATE and DELETE

(RE-CREATE THE TEAMS TABLE)

DML COMMANDS

mysql> insert into teams values (‘12345', ‘Toronto', ‘NE');

Query OK, 1 row affected (0.02 sec)

INSERT

UPDATE teams SET name = ‘TO‘ WHERE name = ‘Toronto';

Query OK, 1 row affected (0.02 sec)

UPDATE

DELETE FROM teams WHERE name = ‘TO';

Query OK, 1 row affected (0.02 sec)

DELETE

load data local infile 'test.txt' into table TEAMS lines terminated by '\r\n';

INSERT DATA FROM TEXT FILE