Property

Overview

Properties are associated with a schema to describe different attributes of the schema. For example, a node schema @card may have properties such as balance and openedOn, while an edge schema @transfersTo may have properties like amount and time.

The expression @<schema>.<property> specifies a certain property of a schema, such as @company.name.

System Property

Each node or edge schema comes with several system properties, which are created automatically with the schema and cannot have their names or types altered. They cannot be deleted either.

Unique Identfier (UID)

Each node has two system properties, _id and _uuid, serving as its unique identifiers. The values of _id for all nodes are distinct, as are the values of _uuid. Additionally, there exists one-to-one correspondence between _id and _uuid.

Each edge has one system property, _uuid, as its unqiue identifer. The values of _uuid for all edges are distinct.

A node and an edge are allowed to have the same value of _uuid.

Custom Property

You can create custom properties for each schema, such as name, type, and time. For more details, please refer to Create Property.

Show Property

UQL
// Show properties of all schemas in the graphset
show().property()

// Show properties of all node schemas in the graphset
show().node_property()

// Show properties of all edge schemas in the graphset
show().edge_property()

// Show properties of @user nodes in the graphset
show().node_property(@user)

// Show properties of @like edges in the graphset
show().edge_property(@like)

Example result:

_nodeProperty

_edgeProperty

The returned result only contains custom properties; system properties are not included.

Create Property

Syntax

Syntax
// Create a property for one node schema in the graphset
create().node_property(@<schema>, "<name>", <type?>, "<desc?>").encrypt()

// Create a property for all node schemas in the graphset
create().node_property(@*, "<name>", <type?>, "<desc?>").encrypt()

// Create a property for one edge schema in the graphset
create().edge_property(@<schema>, "<name>", <type?>, "<desc?>").encrypt()

// Create a property for all edge schemas in the graphset
create().edge_property(@*, "<name>", <type?>, "<desc?>").encrypt()

// Create multiple node/edge properties at one time
create()
  .node_property(@<schema>, "<name>", <type?>, "<desc?>").encrypt()
  .edge_property(@<schema>, "<name>", <type?>, "<desc?>").encrypt()

• Parameters for the node_property() or edge_property() method:
  • @<schema>: Specify the node or edge schema; @* denotes all node or edge schemas.
  • <name>: Name of the property.
  • <type?>: Data type of the property; when it is omitted, the type string is used by default.
  • <desc?>: Description of the property, it's optional.
• Chaining the encrypt() method when you want to encrypt the values of this property:
  • The encryption method is AES128.
  • Only textual-type (string or text) properties allow encryption.

Naming Conventions

Here are the naming conventions for properties:

• Contains 2 to 64 characters.
• Not allowed to start with a tilde symbol ~.
• Not allowed to contain backquote symbol `.
• Not allowed to use any reserved words.

All properties under one schema must have distinct names. Different schemas may contain properties with the same name.

When the property name contains characters other than letters (A-Z, a-z), numbers (0-9) and underscores (_), the property name must be wrapped with a pair of backquotes (`) when being used.

UQL
find().nodes({`Last-name` == "White"}) as n
return n

Create Integer Property

Supported interger data types include int32, uint32, int64 and uint64.

UQL
create().node_property(@course, "credits", int32, "Credits of the course")

Create Decimal Property

Supported decimal data types include float, double and decimal.

UQL
create()
  .node_property(@record, "score", float, "Score of the record")
  .edge_property(@connects, "weight",  "decimal(25,10)", "Weight of the relation")

The decimal(25,10) specifies a decimal type with a precision of 25 digits (total digits) and a scale of 10 digits (digits after the decimal point). You may set the precision between 1 to 65, and the scale between 0 to 30.

Specifically, the type of decimal(<precision>, <scale>) must be declared within two quotes when creating the property.

Create Texual Property

Supported textual data types include string and text.

UQL
create()
  .node_property(@post, "title")
  .node_property(@post, "content", text, "Main content of the post").encrypt()

String is used by default if no type is specified. The encrypt() method only applies to properties with the string or text type.

Create Temporal Property

Supported temporal data types include timestamp and datetime.

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

Create Point Property

Supported point data type is point.

UQL
create().node_property(@city, "position", point, "City location: latitude and longitude")

Create Blob Property

Supported blob data type is blob.

UQL
create()
  .node_property(@user, "profileImg", blob, "Store user profile image as binary large object")

Create List Property

Supported list data types include int32[], int64[], uint32[], uint64[], float[], double[], string[], text[], datetime[] and timestamp[].

UQL
create()
  .node_property(@user, "interests", "string[]", "Store user interest tags as a list of strings")

Specifically, the type of list <element_type>[] must be declared within two quotes when creating the property.

Create Set Property

Supported set data types include set(int32), set(int64), set(uint32), set(uint64), set(float), set(double), set(string), set(text), set(datetime) and set(timestamp).

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

Specifically, the type of set set(<element_type>) must be declared within two quotes when creating the property.

Create a Property for All Schemas

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

Instead of specifying one specific schema name, use @* to denote all node or edge schemas.

Use TRY

Create three edge properties at the same time, but one of the names (time) is duplicated with an existing property.

UQL
create()
  .edge_property(@default, "weight", int32)
  .edge_property(@default, "time", datetime)
  .edge_property(@default, "status", string)

The creation of the property weight, which was specified before the duplicated property, succeeds. However, the one (status) specified after the duplicated property fails, with the error message Property exists! returned.

UQL
TRY create()
  .edge_property(@default, "weight", int32)
  .edge_property(@default, "time", datetime)
  .edge_property(@default, "status", string)

The creation of the properties is the same as above, though the error message is shielded by the TRY prefix, while returning the message SUCCEED.

Alter Property

UQL
// Alter name and description of the node property @user.status in the graphset
alter().node_property(@user.status).set({name: "Status", description: "Active or Inactive"})

// Alter name of the property status of all node schemas (if has) in the graphset
alter().node_property(@*.status).set({name: "state"})

// Modify name and description of the edge property @registers.time in the graphset
alter().node_property(@registers.time)
  .set({name: "createdOn", description: "Time for creation"})

// Modify description of the property time of all edge schemas (if has) in the graphset
alter().edge_property(@*.time).set({description: "Time for creation"})

The data type is not subject to change once a property is created.

Drop Property

Dropping a property entails deleting the property along with all associated property values, LTE-ed values saved in memory, and indexes and full-text indexes created on disk for that property.

UQL
// Drop the node property @card.branch from the graphset
drop().node_property(@card.branch)

// Drop the property branch of all node schemas (if has) from the graphset
drop().node_property(@*.branch)

// Drop the edge property @flows.time from the graphset
drop().edge_property(@flows.time)

// Drop the property time of all edge schemas (if has) from the graphset
drop().edge_property(@*.time)

// Drop multiple node/edge properties at one time
drop()
  .node_property(@card.branch)
  .edge_property(@*.time)