Variant is a data type in programming languages such as Visual Basic and Object Pascal used to represent values that can take on differing data types. It is different from an Object data type, which only stores a reference to an object, and a Variant data type can take on any of a variety of data types.
Variants are used in many different contexts. For example, in Visual Basic, variables declared using the Option Explicit statement must be declared as Variant because Visual Basic does not support many of the primitive data types supported by other languages such as Java and C. In addition, Variants are often the default data type when a variable is declared without a specific type.
Variant data type also allows for implicit type conversion. That is, Visual Basic can automatically convert a Variant from one type to another when it is assigned to, or from, a different type. This can be useful for certain kinds of programming, as it allows for more flexibility in terms of coding.
Variant data types are also sometimes used to store values in certain database systems. For example, Oracle allows for data to be stored in variants, which can then be retrieved and cast to any desired data type.
Variant data types have some drawbacks as well. They are not as efficient as more specific data types, and they may cause problems when trying to serialize data for different environments. As such, it is important to consider the implications of using a Variant data type before implementing it.