Ultipa Graph system provides two types of unique identifiers:
UID |
Data Type |
Supported by |
Explanation |
|---|---|---|---|
| _id | string, maximum length of 128 bytes | node | 1. Similar to the primary key of a relation data table, and can be used to represent actual meaning of the node, such as card number, employee number, etc., 2. The _id of all nodes in a GraphSet remains unique |
| _uuid | uint64 | node, edge | 1. Cannot store non-numeric values and is greatly restricted when being used as unique identifier in the real world 2. In a GraphSet, the _uuid of all nodes remains unique, and so does the _uuid of all edges |
The _id and _uuid of nodes in a GraphSet keep a one-to-one mapping relationship. During the manipulation operation, any data inconsistent with the mapping relation of existing _id and _uuid will lead to failure.
During an insert operation, the ID of metadata can either be provided by user, or be omitted and be generated by the Ultipa Graph system. ID and schema of metadata are NOT subject to change once the metadata is created.