Overview

Properties are linked to a node or edge schema to define the attributes of the corresponding nodes or edges. For example, a node schema card may have properties balance and openedDate, while an edge schema transfers may have properties amount and time.

In UQL, the operator . is used to extract a property from a schema. The expression @<schema>.<property> specifies a certain property of a schema, such as @company.name.

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, which is 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.

Showing Properties

To retrieve information about properties in current graphset:

// Shows all properties
show().property()

// Shows all node properties
show().node_property()

// Shows properties associated with a specified node schema
show().node_property(@card)

// Shows all edge properties
show().edge_property()

// Shows properties associated with a specified edge schema
show().edge_property(@transfers)

The information about properties is organized into different tables:

• Node properties: Stored in _nodeProperty (all properties) and _nodeProperty_shard_N (properties with data in shard N) tables.
• Edge properties: Stored in _edgeProperty (all properties) and _edgeProperty_shard_N (properties with data in shard N) tables.

Each table includes fields that provide essential details about each property:

Creating Properties

You can create one or more properties using a single create() statement. Each property is specified by chaining a node_property() or edge_property() method. To encrypt a property, use the encrypt() method.

create()
  .node_property(<schema>, "<propName>", <propValueType?>, "<propDesc?>").encrypt("<encMeth?>")
  .edge_property(<schema>, "<propName>", <propValueType?>, "<propDesc?>").encrypt("<encMeth?>")
  ...

Integral Properties

The supported integral property value types include int32, uint32, int64 and uint64.

create().node_property(@user, "age", uint32)

Decimal Properties

The supported decimal property value types include float, double, and decimal.

create()
  .edge_property(@links, "distance", float)
  .edge_property(@links, "weight",  "decimal(25,10)", "Weight of the relation")

The decimal(25,10) specifies a decimal type with a precision of 25 (total digits, excluding the decimal point) and a scale of 10 (digits after the decimal point). You may set the precision between 1 to 65, and the scale between 0 to 30. Specifically, decimal(<precision>, <scale>) must be declared within quotes.

Textual Properties

The supported textual property value types include string and text, with string set as the default type. When defining a property as string, you can omit specifying the type during creation.

create()
  .node_property(@post, "title")
  .node_property(@post, "content", text)

Temporal Properties

The supported temporal property value types include datetime and timestamp.

create()
  .node_property(@post, "createdOn", timestamp, "When the post is created")
  .node_property(@post, "publishedOn", datetime, "When the post is published")

Boolean Properties

The supported boolean property value type is bool.

create().node_property(@city, "isCapital", bool, "Indicates whether it is the capital city")

Spatial Properties

The supported spatial property value type is point.

create().node_property(@city, "position", point, "Location of the city")

List Properties

The list property value type includes sub types int32, int64, uint32, uint64, float, double, string, text, datetime and timestamp.

create().node_property(@user, "interests", "string[]", "user interest tags")

Specifically, the <subtype>[] must be declared within quotes.

Set Properties

The set property value type includes sub types int32, int64, uint32, uint64, float, double, string, text, datetime and timestamp.

create()
  .node_property(@user, "heights", "set(float)", "Store user heights history as a set")

Specifically, the set(<subtype>) must be declared within quotes.

Creating a Property for All Schemas

To create the property time for all edge schemas:

create().edge_property(@*, "time", datetime)

Encrypting a Property

To create the property password and encrypt it using AES256:

create().node_property(@user, "password", string).encrypt("AES256")

Altering Name and Description

You can modify the name and description of a property using the alter().node_property().set() or alter().edge_property().set() statement.

In the node_property() or edge_property() method, you can specify a particular property in the form of @<schema>.<property>, or target all properties with the same name in the form of @*.<property>.

To alter both name and description of the node property @user.name:

alter().node_property(@user.name).set({name: "Name", description: "Full name"})

To alter name of all the edge properties time:

alter().edge_property(@*.time).set({name: "createdOn"})

Dropping Properties

You can drop one or more properties using a single drop() statement. Each property is specified by chaining a node_property() or edge_property() method. When a property is dropped, all related data — including the property values, associated indexes, full-text indexes, and any LTE-ed values held in memory — are removed.

In the node_property() or edge_property() method, you can specify a particular property in the form of @<schema>.<property>.

To drop the node property @user.name:

drop().node_property(@user.name)

To drop the edge property @links.time:

drop().edge_property(@links.time)

To drop multiple properties:

drop().node_property(@user.age).edge_property(@links.time)