The varchar (variable character field) is a data type that is used to hold values in programming or database languages. It can have any kind of data, such as characters, numeric, punctuation, or spaces. The data type is able to store values up to its maximum size, depending on the database. Mainly, variable character fields are used to string operations and act as temporary variables. A varchar field is usually initialized with the current length equal to zero, and it has a declared maximum length. Its current length can be from zero to the maximum declared field length. According to the programming language used, the method of declaring a variable character field is different.
The variable character field includes the biggest advantage of the avoidance of padding. In the case of a character field, regardless of the real size of the string, the field occupies the exact number of characters, and the difference between the field length and fixed length is expanded with spaces. In the variable character field, only the minimum storage space is required as it uses the space needed for the size of the string, unlike a character field. It also helps in sorting and searching for values as it includes a feature to avoid any wastage.
Additionally, in some databases and programming languages, if any extra space is found, it removes automatically before storing it to the database. There could be limitations on a variable character field on the basis of the database or the programming language; it cannot be used as a candidate or primary key or cannot be used with a select statement. The variable character field is supported by most relational database management systems.