Databases

A database is an organised collection of data, stored in a structure that lets a computer find and retrieve information quickly. The structure is the important part: instead of keeping information in a pile of separate documents, everything is held in a fixed format that lets the computer locate the data you want.

Tables hold one type of thing

Data in a database is kept in tables. Each table stores data about one type of thing. A community garden might keep one table holding data about its beehives, and a separate table holding data about the gardeners who look after them, because a hive and a gardener are different types of thing. The table below is one table with four fields and three records.

Records and fields

Each row in the table is a record, which brings together every piece of data held about one item. The row H1, Blue, 2, 34 is one complete record, holding everything known about that single hive. A record is always a whole row, never just one value taken from it.

Each column is a field: one particular piece of information that is stored for every record. Every field has a name, such as Colour or JarsHarvested, which labels the column. So a field is a whole column and a record is a whole row, and the two are not the same thing.

Because every record stores exactly the same fields in the same order, the data lines up neatly. A search can go straight to the field it cares about, which is why storing data in tables makes searching so efficient.