MySQL advise on building a database with connected tables - mysql

Question

I want to build a database which holds information about users in a table:
User
-username (primary key)
-first_name
-second_name
-Image
In this database there will be another table like so:
Image
-name (primary key)
-file_name
What I want to achieve
I want each user to have Image as one of its fields. I understand to do this I have to connect the tables.
What I know so far
Firstly I should define the tables as InnoDB, then using phpmyadmin click on relationView.
The Question
How do I achieve the relationship I described above using phpmyadmin?

Answer 1

If a user have only one image it is one to one relationship. Everything can do with a one table.
Something like this:
CREATE TABLE users (
userId INT UNSIGNED NOT NULL AUTO_INCREMENT,
userFirstName VARCHAR(80) NOT NULL,
userSecondName VARCHAR(80),
imageName VARCHAR(100) NOT NULL,
PRIMARY KEY (userId)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
Multiple images have to one user, there is a one to many relationship. So you can create two tables and one lookup table.
Like this:
CREATE TABLE users (
userId INT UNSIGNED NOT NULL AUTO_INCREMENT,
userFirstName VARCHAR(80) NOT NULL,
userSecondName VARCHAR(80),
imageName VARCHAR(100) NOT NULL,
PRIMARY KEY (userId)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
CREATE TABLE images (
imageId INT UNSIGNED NOT NULL AUTO_INCREMENT,
imageName VARCHAR(100) NOT NULL,
PRIMARY KEY (imageId)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
Lookup table:
CREATE TABLE user_image (
userId INT UNSIGNED,
imageId INT UNSIGNED
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

Answer 2

You should put a column on table Image that will be reference on the table User, if for intance, a user can have multiple images. ex,
User
username (primary key)
first_name
second_name
Image
name (primary key)
file_name
userName (Foreign Key)
translated into DDL:
CREATE TABLE `User`
(
userName VARCHAR(15),
first_name VARCHAR(15),
second_name VARCHAR(15),
CONSTRAINT tb_pk PRIMARY KEY (userName),
CONSTRAINT tb_uq UNIQUE (first_name, last_name)
);
CREATE TABLE `Image`
(
name VARCHAR(15),
file_name VARCHAR(75),
userName VARCHAR(15)
CONSTRAINT tb_pk PRIMARY KEY (name),
CONSTRAINT tb_fk FOREIGN KEY (userName) REFERENCES `User`(userName)
);