In a
database, a
record is a set of self-contained data pertaining to one entity in the database. Records are made up of
fields, which contain
data of a certain
type.
Imagine a database of students at a school. Each record would correspond to a student, and be made up of the fields name, address, telephone number, date of birth and a list of subjects the student is studying. You can imagine this as tables of data in a file.
Records may be fixed-length or variable-length. Fixed-length records stay a constant size at all times and therefore can be traversed quickly. For instance, if I know that each record in a database is 200 bytes long, then I can jump straight to record number 4 by jumping 800 bytes into a file. This is called direct access (or random access). Variable-length records allow more flexibility in the size of a file (minimising it, but also allowing it to grow larger if it needs to be done) but means that when accessing the file each record will need to be iterated through on its own, which is slower.