Property is a component of schema that describes the data dimension of entities and relations in the graph. For example, node schema @card (Bank Card) has card number, balance, opening time and other node properties; edge schema @transaction (Transaction) has amount, transfer time and other edge properties.

Node properties _id, _uuid and edge properties _uuid, _from, _to, _from_uuid, _to_uuid are created automatically along with node schema and edge schema. These system properties are not deletable. Each schema may contain multiple properties.

Property features:

• Supported data types of property are: int32, int64, uint32, uint64, float, double, string, text, datetime, timestamp;

• Property is usually combined with schema in the form of @<schema>.<property>, interpreted as “the value of property <property> of nodes/edges of schema <schema>"; independent property expression without schema <property> indicates the value of property <property> for nodes or edges of any schema, or empty value if the property does not exist.

Naming Conventions

Properties are named by developers. A same name can be shared between two properties of different schemas, but not between properties of a same schema.

• 2 ~ 64 characters
• Not allow to start with wave line '~'
• Not allow to contain back quote '`'
• Not allow to use Reserved Words listed in Basic Concepts

Show Property

Returned table name: _nodeProperty and/or _edgeProperty
Returned table header: name | type | lte | schema | description (the name, data type, whether LTEed, schema and description of the property)

Syntax:

// To show properties of all schemas in the current graphset (node properties and edges properties in separated tables)
show().property()

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

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

// To show properties of a certain node schema in the current graphset
show().node_property(@<schema>)

// To show properties of a certain edge schema in the current graphset
show().edge_property(@<schema>)

Create Property

string is used by default if data type is ignored when creating property.

Syntax:

// To create a node property under a certain node schema in the current graphset
create().node_property(@<schema>, "<name>", <type?>, "<desc?>")

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

// To create an edge property under a certain edge schema in the current graphset
create().edge_property(@<schema>, "<name>", <type?>, "<desc?>")

// To create an edge property under all edge schemas in the current graphset
create().edge_property(@*, "<name>", <type?>, "<desc?>")

// To create multiple node/edge properties by using the four methods above
create()
  .node_property(@<schema>, "<name>", <type?>, "<desc?>")
  .node_property(@*, "<name>", <type?>, "<desc?>")
  .edge_property(@<schema>, "<name>", <type?>, "<desc?>")
  .edge_property(@*, "<name>", <type?>, "<desc?>")

Example: Using one UQL to create node properties "card balance" and "level" under @card and edge property "time" for all edge schemas

create().node_property(@card, "sum," double, "card balance")
  .node_property(@card, "level", int, "card level")
  .edge_property(@*, "time", datetime)

Example: Using one UQL to create edge properties "transaction number", "time" and "amount" under @transaction

create().edge_property(@transaction, "no", "", "transaction number")
  .edge_property(@transaction, "time", datetime)
  .edge_property(@transaction, "amount", double)

Example: Using one UQL to create node properties "card balance", "level" under @card and edge properties "transaction number", "time" and "amount" under @transaction

create().node_property(@card, "sum", double, "card balance")
  .node_property(@card, "level", int, "card level")
  .edge_property(@transaction, "no", "", "transaction number")
  .edge_property(@transaction, "time", datetime)
  .edge_property(@transaction, "amount", double)

Alter Property (Name, Description)

Syntax:

// To modify the name, description of a certain node property under a certain node schema in the current graphset
alter().node_property(@<schema>.<property>)
  .set({name: "<new_name?>", description: "<new_desc?>"})

// To modify the name, description of a certain node property (if has) under all node schemas in the current graphset
alter().node_property(@*.<property>)
  .set({name: "<new_name?>", description: "<new_desc?>"})

// To modify the name, description of a certain edge property under a certain edge schema in the current graphset
alter().edge_property(@<schema>.<property>)
  .set({name: "<new_name?>", description: "<new_desc?>"})

// To modify the name, description of a certain edge property (if has) under all edge schemas in the current graphset
alter().edge_property(@*.<property>)
  .set({name: "<new_name?>", description: "<new_desc?>"})

Example: Rename @card property "sum" as "balance"

alter().node_property(@card.sum)
  .set({name: "balance"})

Example: Rename property "time" as "createTime" for all edges

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

Drop Property

User may delete properties that are no longer needed to save disk space. Deleting property operation can be executed in real time, and there will not be a considerable wait time. Once executed, the property is deleted immediately.

Except for system properties _id, _uuid, _from, _to, _from_uuid and _to_uuid which are not allowed to be deleted, all the other properties of schema can be deleted.

Syntax:

// To delete a certain node property under a certain node schema from the current graphset
drop().node_schema(@<schema>.<property>)

// To delete a certain node property (if has) under all node schemas from the current graphset
drop().node_schema(@*.<property>)

// To delete a certain edge property under a certain edge schema from the current graphset
drop().edge_schema(@<schema>.<property>)

// To delete a certain edge property (if has) under all edge schemas from the current graphset
drop().edge_schema(@*.<property>)

// To delete multiple node/edge properties by using the four methods above
drop()
  .node_schema(@<schema>.<property>)
  .node_schema(@*.<property>)
  .edge_schema(@<schema>.<property>)
  .edge_schema(@*.<property>)

Example: Delete node property "branch" under @card and edge property "time" for all edges

drop().node_property(@card.branch).edge_property(@*.time)

Example: Delete @default edge property "test"

drop().edge_property(@default.test)