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How should I set up my database / table, if I do not know the number of fields I would populate per record?
For example, if I have a web form that allows a user to enter all the cars he owns, and I don't want to limit him to a certain number, how would I store this in the database end?
The above problem extends to similar situations such as storing a user's order (variable number of items per order) etc.
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More information. In Access, you can define up to 255 fields in a table. If you create 255 fields and then delete 10, Access does not release the fields from the internal column count.
Collection of fields is called records. In a database, a record is a group of fields within a table that are relevant to a specific entity. Records are composed of fields, each of which contains one item of information. A set of records constitutes a file.
There is no constraint on number of fields in database theory. A table can be limited to a primary key (even if this primary key is made of 2 fields), meaning that Apocalisp's answer is not very clear. At the opposit, a table can be made out of thousends of fields, as long as normal form rules are respected.
In Relational Database Management Systems (RDBMS) instead you create child records in a dependent table that relate child entities (cars) with parent entities (users). There is a concept known as database normalization, and the objective is that each table contains data for a single type of entity.
So you have a user table with the user information:
user_id | user_name | email | ...
1234 | User1 | [email protected] | ...
2356 | User2 | [email protected] | ...
Then another table for storing the information of each car of a user:
user_car_id | user_id | car_label | make | model | ...
1 | 1234 | MyCar | Ford | 2011 | ...
2 | 2356 | A Car | Chevrolet | 2010 | ...
3 | 1234 | MyOtherCar| BMW | 2000 | ...
So instead of storing the info of the cars in the user table, you have a table for storing car (user_car) information related to each user by way of the user_id column. This is an example of a one-to-many relationship, in which one user can have many related cars.
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this is an entire topic: database normalization.
the short answer is you make more than one table.
in your example you would have person table, a car table, and a third that linked person to the car
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