DAT702. Standard Query Language Ability to access and manipulate databases ◦ Retrieve data ◦...
-
Upload
ross-eaton -
Category
Documents
-
view
215 -
download
0
Transcript of DAT702. Standard Query Language Ability to access and manipulate databases ◦ Retrieve data ◦...
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