[postgis-users] AddGeometryCOlumn error on View

[Piotr Synowiec]

Hi
I have view created from 2 tables to select and combine data I need.
I tried to add geometry column with below command but it failed.
SELECT AddGeometryColumn( 'my_view', 'geom_field', -1, 'GEOMETRY',2);

Instead I used
INSERT INTO geometry_columns 
(f_table_catalog,f_table_schema,f_table_name,f_geometry_column,coord_dimension,srid,type) 
VALUES ('','public','my_view','geom_field',2,-1,'GEOMETRY')

and it worked, why shouldn't.

I can use this view as geometry drawing in Manifold.
I can't use it in QGIS, as QGIS complains that view doesn't have a 
unique ID column.

Is there any particular reason why AddGeoemtryColumn doesn't work on Views ?

Another question is how to create unique ID for a View ?

Regards
Piotr