NGSIPostGISSink
Content:
Functionality
com.iot.telefonica.cygnus.sinks.NGSIPostGISSink
, or simply NGSIPostGISSink
is a sink designed to persist NGSI-like context data events within a PostGIS server which is relational database extension of PostgreSQL server which allows store GIS objects (Geographic Information Systems). Usually, such a context data is notified by a Orion Context Broker instance, but could be any other system speaking the NGSI language.
Independently of the data generator, NGSI context data is always transformed into internal NGSIEvent
objects at Cygnus sources. In the end, the information within these events must be mapped into specific PostgreSQL data structures.
For futher detail please refear to NGSIPostgreSQLSink
Basically PostGIS sink translates NGSI attribute value about geometry (geo:point, geo:json) to PostGIS format and insert it.
geo:point -> ST_SetSRID(ST_MakePoint())
geo:json -> ST_GeomFromGeoJSON()
Colum should be provisioned as type geometry
CREATE TABLE myTable ( geom geometry );
Administration guide
Please refear to NGSIPostgreSQLSink
since all administration options about PostgreSQLSink applies to PostGISSink.
Programmers guide
Please refear to NGSIPostgreSQLSink
since all programing details about PostgreSQLSink applies to PostGISSink.
Native types
Regarding the specific data stored within the above table, if attr_native_types
parameter is set to true
then attribute is inserted using its native type (according with the following table), if false
then will be stringify.
Type json | Type PostGreSQL/POSTGIS |
---|---|
string | text |
number | double, precision, real, others (numeric, decimal) |
boolean | boolean (TRUE, FALSE, NULL) |
DateTime | timestamp, timestamp with time zone, timestamp without time zone |
json | text o json - it`s treated as String |
null | NULL |
This only applies to Column mode.