A fundamental data type that holds character information. A String variable is either fixed-length or variable-length and contains one character per byte. Fixed-length strings are declared to be a specific length and can contain 1 to approximately 64K (2^16) characters. Variable-length strings can be any length up to 2 billion (2^31) characters (approximately 64K [2^16] characters for Microsoft Windows version 3.1 and earlier), less a small amount of storage overhead.