Visual Basic Data types
Data is information that will be processed by your application, and broadly speaking can be categorised as being numeric, character-based (i.e. alpha-numeric characters or strings) or a collection of attributes that represent various kinds of object.
Variables are memory locations that hold the data values assigned to them at any given time. Each variable has a name, an address in memory, and a size (usually measured in bytes) that determines the amount of memory it occupies. The variable's size is dependent on its data type. The size of a standard ASCII character variable, for example, is 1 byte.
The table below lists the numeric data types supported by Visual Basic.
| Type | Bits | Description | Min | Max |
|---|---|---|---|---|
| Byte | 8 | Unsigned integer | 0 | 255 |
| SByte | 8 | Signed integer | -128 | 127 |
| Short | 16 | Signed (short) integer | -32,768 | 32,767 |
| UShort | 16 | Unsigned (short) integer | 0 | 65,535 |
| Integer | 32 | Signed integer | -2,147,483,648 | 2,147,483,647 |
| UInteger | 32 | Unsigned integer | 0 | 4,294,967,295 |
| Long | 64 | Signed (long) integer | -9,223,372,036,854,775,808 | 9,223,372,036,854,775,807 |
| ULong | 64 | Unsigned (long) integer | 0 | 18,446,744,073,709,551,615 |
| Single | 32 | Single-precision floating point number | -3.4028235E38 | 3.4028235E38 |
| Double | 64 | Double-precision floating point number | -1.79769313486231E308 | 1.79769313486231E308 |
| Decimal | 128 | Decimal number * | -7.92E+28 | 7.92E+28 |
* Values depend on whether or not a decimal point is used and if so how many places to the right of the decimal point (up to a maximum of 28) are used. For example, if all 28 places are used, the range of values that can be represented is -7.9228162514264337593543950335 to 7.9228162514264337593543950335.
The table below lists some of the non-numeric data types supported by Visual Basic.
| Type | Description |
|---|---|
| Boolean | A data type that can only evaluate to True (non-zero) or False (zero). |
| Char | A Unicode character code in the range 0 to 65,535. |
| String | A sequence of zero or more unsigned 16-bit code points (character codes) that can range in value from 0 to 65535. Each code point represents a single Unicode character. A string can contain from zero to approximately two billion (231) Unicode characters. |
| Date | Can hold 64-bit DateTime values in the range 0:00:00, January 1 of the year 0001 to 23:59:5999999, December 31 of the year 9999. Each increment represents 100 nanoseconds of elapsed time since the beginning of January 1 of the year 1 in the Gregorian calendar. The maximum value represents 100 nanoseconds before the beginning of January 1 of the year 10000. |
| Object | A variable of type object can store any data type. Objects are referenced using 32-bit pointer variable or or a 64-bit pointer variable, depending on whether the code is running on a 32-bit or a 64-bit platform. |