ST_addEvent-AnalyticDB(AnalyticDB)-阿里云帮助中心

Adds an event to a trajectory object and returns a new trajectory with the event included.

Syntax

trajectory ST_addEvent(trajectory traj, integer event_type, timestamp event_time);

Parameters

Parameter	Type	Description
`traj`	`trajectory`	The trajectory object to add the event to.
`event_type`	`integer`	The event type ID.
`event_time`	`timestamp`	The timestamp of the event.

Description

ST_addEvent returns a new trajectory object that includes the added event. The original trajectory object is not modified.

Event type IDs are predefined. For example, 1000 for unlocking and 2000 for locking.

The added event appears in the events array of the returned trajectory JSON.

Examples

The following example adds event type 1 at timestamp 2010-01-01 11:30:00 to a trajectory object.

WITH traj AS (
  SELECT '{"trajectory":{"version":1,"type":"STPOINT","leafcount":2,"start_time":"2010-01-01 11:30:00","end_time":"2010-01-01 12:30:00","spatial":"SRID=4326;LINESTRING(1 1,3 5)","timeline":["2010-01-01 11:30:00","2010-01-01 12:30:00"],"attributes":{"leafcount":2,"velocity":{"type":"integer","length":4,"nullable":true,"value":[1,null]},"speed":{"type":"float","length":8,"nullable":true,"value":[null,1.0]},"angle":{"type":"string","length":64,"nullable":true,"value":["test",null]},"tngel2":{"type":"timestamp","length":8,"nullable":true,"value":["2010-01-01 12:30:00",null]},"bearing":{"type":"bool","length":1,"nullable":true,"value":[null,true]}}}}'::trajectory a)
SELECT ST_addEvent(a, 1, '2010-01-01 11:30:00') FROM traj;

The returned trajectory JSON includes a new "events":[{"1":"2010-01-01 11:30:00"}] field:

{"trajectory":{"version":1,"type":"STPOINT","leafcount":2,"start_time":"2010-01-01 11:30:00","end_time":"2010-01-01 12:30:00","spatial":"SRID=4326;LINESTRING(1 1,3 5)","timeline":["2010-01-01 11:30:00","2010-01-01 12:30:00"],"attributes":{"leafcount":2,"velocity":{"type":"integer","length":4,"nullable":true,"value":[1,null]},"speed":{"type":"float","length":8,"nullable":true,"value":[null,1.0]},"angle":{"type":"string","length":64,"nullable":true,"value":["test",null]},"tngel2":{"type":"timestamp","length":8,"nullable":true,"value":["2010-01-01 12:30:00",null]},"bearing":{"type":"bool","length":1,"nullable":true,"value":[null,true]}},"events":[{"1":"2010-01-01 11:30:00"}]}}
(1 row)