1. Database commands : DDL
ARK2100
Digital recordkeeping and preservation I
2016
Thomas Sødring
P48-R407

2. So far We have explored The concept of databases
The relational model and related issues
ER-modelling
Conceptual, logical and physical
We should now have a basic understanding of what this means are how this related to eachother
Now we will look at how to implement a model in the database
Inserting, updating and retrieving data from a database
This is a slow process so we have to be patient!!

3. We will learn about Datatypes
What they are, why they are important and how to choose them
The DDL commands
CREATE, DROP, ALTER, TRUNCATE

4. First we need access to MySQL
Fisrt you have to create a database account
Click on 'Opprett MySQL-konto'
Means Create mysql account!
Then you can log on
If you forget or have problems with your password
Click on 'Bytt MySQL-passord'
Means Change MySQL password

5. Create database account
Your student number
Check the format!
Password you want
VERY IMPORTANT!!
Do not use the password you use to log on fronter / HiOA or HiOA computers!
Do not use a password that you use to log on to gmail / facebook etc
Choose something like '_23Frank'

6. https://bibin.hioa.no/phpmyadmin/

7. DBMS
Schema A
Schema B r1 r2 r3 r1 r2 r5 r3 r4 r6 r7
A database management system can contain many schemas. People often call a schema a database and use the terms interchangeably.

8. Data is stored in a relation (table)
Cars
RegistrationNr
ChassisNr
Colour
Manufacturer
Model
LH12984
Red
Volkswagen
Golf
DK23491
Blue
Toyota
Yaris
BP12349
Green
Skoda
Fabia
ZT97495
White
Seat
Leon

9. Relation, Attributtes, Tuples
RegistrationNr
ChassisNr
Colour
Manufacturer
Model
Cars
LH12984
Red
Volkswagen
Golf
4 Tuples
DK23491
Blue
Toyota
Yaris
BP12349
Green
Skoda
Fabia
ZT97495
White
Seat
Leon
5 Attributtes

10. Data Definition Language (DDL)
Data Definition Language (DDL) is a database language that can be used to define a database schema
A database schema is a metadata description of one or more tables (relations) in a database r1 r2 r3 r5 r4 r6 r7
Schema A
Schema B

11. Data Definition Language (DDL)
DDL is also used to define
attribute names (columns)
data types
relationships to other tables
RegistrationNr
ChassisNr
Colour
Manufacturer
Model
Cars
CREATE TABLE Car (
RegistrationNr VARCHAR(20),
ChassisNr VARCHAR(20),
Manufacturer VARCHAR(30),
Model VARCHAR(20),
Colour VARCHAR(20),
PRIMARY KEY (RegistrationNr) )

12. Datatypes
Databases are very fussy about the knowing what kind of data they are storing
Each column needs its datatype set
The data type applies to all values in the attribute
These can for example be:
String, number, date, time
All DBMS supports a set of datatypes that can be set on attributes (columns)
We look at the data types of MySQL
RegistrationNr
ChassisNr
Colour
Manufacturer
Model
Cars

13. Why datatypes
Efficiency, to reduce storage space and compatibility with programming languages
Also helps error handling
Efficiency
Helps optimise storage of data for querying
Items that consist of numbers should be configured as integers (INT) if we know that they will be used for calculations (e.g. average, count, summation)
Storage reduction
You do not want your database using space that is not required
eg country codes consisting of a maximum of 2 letters (NO, SE, DK, FI, D)
CHAR (2)
Programming languages use datatypes

14. Datatypes (string) Datatype Type Description CHAR () Fixed
A field of fixed length that can consist of between 0 og 255 characters. The length can be specified
VARCHAR ()
Variable
A field of variable length that can consist of between 0 og 255 characters. The length can be specified
TINYTEXT
A field of variable length that can consist of a maximum of 255 characters
TEXT
A field of variable length that can consist of a maximum of characters
MEDIUMTEXT
A field of variable length that can consist of a maximum of characters
LONGTEXT
A field of variable length that can consist of a maximum of characters

15. Datatypes (BLOB)
Binary Large OBject is a field that can be used to store binary data for example a MS Word (.doc) file
When the Word file is stored on disk, you cannot read it
You need a program to decipher the data and display it for you
Datatype
Description
TINYBLOB
A field of variable length that can consist of a maximum of 255 characters
BLOB
A field of variable length that can consist of a maximum of characters
MEDIUMBLOB
A field of variable length that can consist of a maximum of characters
LARGEBLOB
A field of variable length that can consist of a maximum of characters

16. Binary data
Binary data is data encoded such that only a computer can read it
A human cannot read it
Consists of 1's and 0's

17. Datatypes (whole numbers)
Calculations (e.g. average age) are performed faster when an attribute is specified as a number
It is important to know what the max and min value of the data type
Maximum Value + 1 = Minimum value
Datatype
Description
TINYINT
A number between 0 and 255 or -128 and 127
SMALLINT
A number between 0 and or and 32767
MEDIUMINT
INT
A number between 0 and or and
BIGINT
A number between 0 and or and

18. Wrap around

19. Datatypes (other numbers)
Decimal number e.g uses the following data types
FLOAT
DOUBLE
DECIMAL
If you just require to store a yes or no value, you can use a
BOOLEAN

20. Datatypes (date and time)
Description
DATE
A date between the year and the year
DATETIME
A date and time between the year :00:00 and the date and time :59:59
TIME
Number of hours:minutes:seconds from -838:59:59 til 838:59:59
YEAR[(2|4)]
A year value between 1901 to 2155
TIMESTAMP
Number of seconds since a given time (point in history)

21. So far We have again looked at the concept of a DBMS
How data is stored in relations
Introduced the concept of datatypes
We have to know the datatype for every value in the database
String, number, date etc
Now we are going to work with a DBMS called MySQL

22. phpMyAdmin MySQL and phpMyAdmin
phpMyAdmin is a program that can be used to access a MySQL DBMS
phpMyAdmin r1 r2 r3
Schema A r5 r4 r6 r7
Schema B

23. https://bibin.hioa.no/phpmyadmin/
Choose the language you wish to work with

24. Data Definition Language (DDL)
DDL Commands
CREATE
create
DROP
delete
ALTER
change
TRUNCATE
empty

25. DDL CREATE CREATE can be used to create the following:
Schema (database)
Relation (table)
User

26. {DATABASE | SCHEMA} [IF NOT EXISTS] db_navn;
CREATE Syntax
CREATE
{DATABASE | SCHEMA} [IF NOT EXISTS] db_navn;

27. A syntax explanation MySQL DDL uses the following syntax { }
means that you must select an item from a set of elements |
Means either or
select | insert
Choose either select or insert
[ ]
Means it is optional

28. CREATE DATABASE s123456_database;
Use your student number - not s123456!
The database server at HiOA is set up with a requirement that each database name must always start with your student number
If you forget studentnummer_ you will get an error!

29. ; semicolon Always use a semicolon after each database statement
This allows us to run multiple commands in one go ;

30. USE command CREATE DATABASE s123456_firstdatabase;
You usually have to specify the name of database you are working with
The reason for this is that you will have many databases and the DBMS needs to know which one you want to work with
CREATE DATABASE s123456_firstdatabase;
USE s123456_firstdatabase;

31. phpMyAdmin

32. Entering SQL commands

33. Create a database
1. Write in the DDL command
2. Press 'Go'

34. Result of create

35. Choose database 1. Here you will see all your databases
2. Click on the database you wish to work with

36. Back to a SQL window
1. Back to an SQL window

37. Ready to go

38. [attribute properties] )
CREATE (table)
CREATE
TABLE [tablename] (
[attribute properties] )
Remember to specify which database you are using

39. Entity examples Car Airport Building RegistrationNr ChassisNr Colour
Manufacturer
Model
Name
Name
Location
Int Code
Address
Town
Country
Postnumber
Town

40. Logical model Airport (Name, IntCode, Town, Country)
Car (RegistrationNr, ChassisNr, Colour, Manufacturer, Model)
Airport (Name, IntCode, Town, Country)
Building (Name, Location, Address, Postnumber, Town)
All we are missing is the datatypes. Once we have this we can write DDL.

41. From a logical to a physical model
CREATE TABLE Car (
RegistrationNr VARCHAR(20),
ChassisNr VARCHAR(20),
Manufacturer VARCHAR(30),
Model VARCHAR(20),
Colour VARCHAR(20),
PRIMARY KEY (RegistrationNr) );
CREATE TABLE Airport (
Name VARCHAR(20),
IntCode CHAR(3),
Town VARCHAR(20),
Country VARCHAR(20),
PRIMARY KEY (Name) );
CREATE TABLE Building (
Name VARCHAR(20),
Location VARCHAR(30),
Address VARCHAR(30),
Postnumber VARCHAR(4),
Town VARCHAR(100),
PRIMARY KEY (Name) );

42. Create Car CREATE TABLE Car ( RegistrationNr VARCHAR(20),
ChassisNr VARCHAR(20),
Manufacturer VARCHAR(30),
Model VARCHAR(20),
Colour VARCHAR(20),
PRIMARY KEY (RegistrationNr) );
Remember the semicolon
Never a comma at the end

43. DDL for Car
1. Write in the DDL command
2. Press 'Go'

44. Result of Create Car

45. Structure of Car

46. Create Airport CREATE TABLE Airport ( Name VARCHAR(20),
IntCode CHAR(3),
Town VARCHAR(20),
Country VARCHAR(20),
PRIMARY KEY (Name) );
Remember the semicolon
Never a comma at the end

47. DDL for Airport
1. Write in the DDL command
2. Press 'Go'

48. Result of Create Airport

49. Structure of Airport

50. Create Building CREATE TABLE Building ( Name VARCHAR(20),
Location VARCHAR(30),
Address VARCHAR(30),
Postnumber VARCHAR(4),
Town VARCHAR(100),
PRIMARY KEY (Name) );
Remember the semicolon
Never a comma at the end

51. DDL for Building
1. Write in the DDL command
2. Press 'Go'

52. Result of Create Building

53. Structure of Building

54. Distributor
distributorID
name
address
postnr
town
Contributor
Film
filmId
personId
firstname
surname
dob
deathDate
title
year
length
manufacturer
Participation
distributorID
filmId
personId
role
customerNr
Customer
firstname
surname
address
postnr
town
Booking
bookingId
time
amount
filmId
customerNr
Theater
theaterNr
capacity
filmId

55. CREATE DATABASE s123456_cinema;
Cinema database
First we create a new Schema
Then we will create the tables
The DDL commands can be downloaded from
0cinema%20en.sql
CREATE DATABASE s123456_cinema;

56. Create Cinema

57. DDL for Create database

58. Result of Create database

59. SQL window for Cinema database

60. ER model Contributor (personId, firstname, surname, dob, deathDate)
Film (filmId, title, year, length, manufacturer, distributorId*)
Distributor (distributorId, name, address, postnr, town)
Customer (customerNr, firstname, surname, address, postnr, town)
Theater (theaterNr, capacity, filmId)
Participation (filmId*, personId*, role)
Booking (filmId*, customerNr*, bookingDate, time, amount)

61. CREATE TABLE Contributor (
personId INT NOT NULL AUTO_INCREMENT,
firstname VARCHAR(30),
surname VARCHAR(30),
dob DATE,
deathDate DATE,
PRIMARY KEY (personId)
) engine = innoDB;
CREATE TABLE Theater (
theaterNr INT NOT NULL,
capacity INT,
filmId INT,
PRIMARY KEY (theaterNr),
FOREIGN KEY (filmId) REFERENCES Film (filmId)
) engine = innoDB;
CREATE TABLE Distributor (
distributorId INT NOT NULL AUTO_INCREMENT,
address VARCHAR(100),
postnr VARCHAR(4),
town VARCHAR(100),
PRIMARY KEY (distributorId)
) engine = innoDB;
CREATE TABLE Participation (
filmId INT,
personId INT,
role VARCHAR(100),
PRIMARY KEY (filmId, personId, role),
FOREIGN KEY (filmId) REFERENCES Film (filmId),
FOREIGN KEY (personId) REFERENCES
Contributor (personId)
) engine = innoDB;
CREATE TABLE Film (
filmId INT NOT NULL AUTO_INCREMENT,
tittle VARCHAR(30),
year CHAR(4),
length INT,
manufacturer VARCHAR(30),
distributorId INT,
PRIMARY KEY (filmId),
FOREIGN KEY (distributorId) REFERENCES
Distributor (distributorId)
) engine = innoDB;
CREATE TABLE Booking (
filmId INT,
customerNr INT,
bookingDate DATE,
time TIME,
amount INT,
PRIMARY KEY (filmId, customerNr, bookingDate, time),
FOREIGN KEY (filmId) REFERENCES Film (filmId),
FOREIGN KEY (customerNr) REFERENCES
Customer (customerNr)
) engine = innoDB;
CREATE TABLE Customer (
customerNr INT NOT NULL AUTO_INCREMENT,
firstname VARCHAR(30),
surname VARCHAR(30),
address VARCHAR(100),
postnumber VARCHAR(4),
town VARCHAR(100),
PRIMARY KEY (customerNr)
) engine = innoDB;

62. DDL for Create Cinema
1. Write in the DDL command
2. Press 'Go'

63. Cinema database structure

64. CREATE USER user [IDENTIFIED BY PASSWORD] 'passord']
CREATE a database user
CREATE USER user [IDENTIFIED BY PASSWORD] 'passord']
We do not have the right to run this command

65. DROP Everything you can CREATE, you can DROP (delete) Database Table
User

66. {DATABASE | SCHEMA} [IF EXISTS] db_navn;
DROP Syntax
DROP
{DATABASE | SCHEMA} [IF EXISTS]
db_navn;

67. DROP DROP {DATABASE | SCHEMA} [IF EXISTS] db_name;
DROP TABLE [IF EXISTS]
table_name [, table_nameN];
DROP USER user [, userN];

68. TRUNCATE Sometimes you may want to delete all the contents of a table
Easiest way to do this is with the truncate command
USE s123456_firstdatabase;
TRUNCATE Car;

69. ALTER After you have created a table, you may need to change it, eg
Add a new column to a table
Change the primary key

70. ALTER examples USE s123456_firstdatabase;
ALTER TABLE Car ADD MotorCC VARCHAR(255);
ALTER TABLE Car DROP MotorCC;
USE s123456_firstdatabase;
ALTER TABLE Airport ADD Continent VARCHAR(255);
ALTER TABLE Airport DROP Continent;

71. So far
We have looked at one DBMS called MySQL and use a program called phpMyAdmin to work with MySQL
We looked at datatypes
We looked at some DDL commands
CREATE database and tables
DROP database / DELETE
ALTER a table
We have not looked at how to insert data or retrieve data