Question

I am setting up a MySQL database and will be querying it with PHP. Is is better to break the information up into multiple tables and do select queries on each of the tables; or is it better to put all the items in one table and do a single select query?

For example:

It will hold information on upto 7 cars; which would mean that their will be approximately 50 columns or so.

Table_design 1
----------------------
table_all
    username
    car1_make
    car1_model
    car1_year
    car1_condition
    car1_tires
    car1_color
    car2_make
    car2_model
    car2_year
    car2_condition
    car2_tires
    car2_color
----------------------

Table_design 2
----------------------
table_1
    username
    car1_make
    car1_model
    car1_year
    car1_condition
    car1_tires
    car1_color

table_2
    username
    car2_make
    car2_model
    car2_year
    car2_condition
    car2_tires
    car2_color
----------------------

Answer 1

Three tables. This way you’re not limited to the amount of information you can add to a car. And you’re not limited to the number of cars a user can have access to.

If you ever need a spreadsheet of users, query the users table. If you ever need an inventory of cars, query the cars table. If you ever need to know which cars each users are associated with, query the userscars.

See Database Normalization.

• users
  • User ID
  • User First Name
  • User Last Name
• cars
  • Car ID
  • Car Make
  • Car Model
• usercars
  • User ID
  • Car ID