当实体 id 包含特殊字符时，Fiware Cygnus PostgreSQL sink 不会创建表

Question

It appears that cygnus-ngsi and its PosgreSQL sink can't create a postgres table when the entity has an id that contains the - chracter, eg urn:ngsi-ld:Motion:001 as recommended in the Fiware tutorials .

I setup a simple stack with Orion, an IoT-Agent as well as Cygnus-NGSI and a PostgreSQL database.

However, PostgreSQL reports the error

2020-11-10 08:39:33.404 UTC [66] ERROR: syntax error at or near "-" at character 44
2020-11-10 08:39:33.404 UTC [66] STATEMENT: CREATE TABLE IF NOT EXISTS openiot.urn_ngsi-ld_motion_001_thing (recvTimeTs text,recvTime text,fiwareServicePath text,entityId text,entityType text,attrName text,attrType text,attrValue text,attrMd text)

The error does not occur when a different entity id is used. Data is then persisted as expected.

Cygnus should replace non-alphanumeric characters inentity ids with _ , however, that does not appear to be happening. Is this just a bug or do I need some sort of name mapping to solve this?

Answer 1

Looking to encoding section in the Postgresql sink documentation it seems no special encoding is done for - .

Thus, - progresses as it is to Postgresql table creation logic and raises an error, due to it is forbidden in table names by the database.

You can explore the name mappings option (although I'm not sure if you can change entity ids using it...). Another possible workaround (pretty simple) is not using - in entity ids, eg: urn:ngsild:Motion:001