Ultipa Graph system provides two types of unique identifiers: UUID and ID. UUID is of int64 type with the property name _uuid and is supported by both node and edge. ID is stored as a string with the maximum length of 128 bytes, and the property name is _id, ID is supported by node only and can be used to represent some actual meaning of the node, such as card number, employee number, etc., hence is more frequently used than UUID in a query.

The UUID and ID of nodes in a GraphSet keep a one-to-one mapping relationship.