When we want information from a book, we look in the index to find the relevant page. A database works in the same way. It sets up at least one main index to work out where each record can be found. This index is called the primary key.
Another thing to bear in mind is that each field can be set up so that only certain types of data can be entered into them. It could be that you set a field to only accept text or numbers, or a field could be set to automatically enter either a date or a unique number as you create the record.
Chris has started work on the membership database. He decides that the membership number is the number that the database will use as the primary key to sort out the different records.
He could type in the number manually into a number field, but as this is the primary key this may make things difficult later - he’d have to keep track of which number he was up to and might use the same number by accident.
Instead, he sets the database to automatically increment this number each time a new record is made. Doing it this way ensures they are unique and also makes it a little more future proof - other people could add to the database simultaneously should his business expand.
Chris is now setting the data types on his membership database. There are several types of information that he needs to store.
