An instance of the Ultipa graph database can host one or more graphs (or graphsets), each representing a unique dataset or domain of interconnected nodes and edges.

The data within a graph adheres to its graph structure. It defines the structural rules and constraints of a graph by outlining the permissible node schemas and edge schemas, along with the associated property types for each schema.

GQL Conformance Note

The Graph Structure, Node Schema, and Edge Schema align with the Graph Type, Node Type, and Edge Type defined in the ISO GQL standard.

Node Schema

A node schema defines a type of nodes allowed in the graph. It comprises a node schema name and a set of property types.

For example, a User node schema includes properties name (string type) and age (int32 type):

NODE User ({name string, age int32})

The schema name User also serves as a label. This schema can be referenced using the label expression :User.

Each graph comes with a built-in node schema named default. The default node schema is available for free use but cannot be be renamed or deleted.

Edge Schema

An edge schema defines a type of directed edges between nodes. It comprises an edge schema name and a set of property types.

For example, a Links edge schema connects any two nodes and includes a property description (string type):

EDGE Links ()-[{description string}]->()

The schema name Links also serves as a label. This schema can be referenced using the label expression :Links.

Each graph comes with a built-in edge schema named default. The default edge schema is available for free use but cannot be be renamed or deleted.

Property Type

Properties are associated with a node or edge schema to describe attributes of nodes and edges. A property type is defined by a property name and its property value type. For example, a name property with the value type string.

Property Naming Conventions →
All Property Value Types →

System Property

Each node has two system properties serving as unique identifiers: _id and _uuid. The _id value can be manually assigned, ensuring distinct identification of nodes, while the _uuid value is always generated by the system.

Each edge has only the _uuid as its unique identifier, also generated by the system. Each edge connects a source node to a destination node, its _from/_to and _from_uuid/_to_uuid identify its two end nodes.

Naming Conventions

Graph

The names of all graphs in a database must be unique. Each graph name must:

• Contain 2 to 64 characters.
• Begin with a letter.
• Allowed characters: letters (A-Z, a-z), numbers (0-9) and underscores (_).

Node Schema and Edge Schema

Each node or edge schema name must:

• Contain 2 to 64 characters.
• Cannot start with a tilde (~).
• Cannot contain backquotes (`).
• Cannot use system property names or reserved keywords.

Node schema names must be unique among node schemas, and edge schema names must be unique among edge schemas. However, a node schema and an edge schema are allowed to share the same name.

Property

Each property name must:

• Contain 2 to 64 characters.
• Cannot start with a tilde (~).
• Cannot contain backquotes (`).
• Cannot use system property names or reserved keywords.

Property names must be unique among a node schema or an edge schema.