An "Index" is an associative key-value array (or dictionary) that is physically stored either in or alongside a database table and it allows for a performant way to retrieve one or more specific records in a database. The index is sorted by key and thus also defines an ordering of records retrieved via this index. |
The "Key" is the sequence of bytes that is used to locate an item in the index, and the "Value" is
a reference to the actual record. A database table typically has multiple indexes allowing to find the required records for different usage cases. |
A key is composed of one or more "Key segments". In the case of Venice the value in a key segment will always be equal to a field in the record. Each key segment has its own type, collation, and ordering. |