- Variable-length records arise in database systems in several ways:
- Storage of multiple record types in a file.
- Record types that allow variable lengths for one or more fields such as strings (varchar)
- Record types that allow repeating fields (used in some older data models).
- Attributes are stored in order
- Variable length attributes represented by fixed size (offset, length), with actual data stored after all fixed length attributes
- Null values represented by null-value bitmap