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I am trying to save a Point Type into Postgresql I have tried this way. (Db table Model definition)

 public NpgsqlPoint Position { get; set; }

I set the Object with this method 

  posData.Position = new NpgsqlPoint (34.3244,23.2344);

But when i call .SaveChanges on the dbContext i get an exception of Not Null Constraint Violation , so i guess EF is trying to insert a null.

I have debuged the posData.Position before entry and the object contains proper data.

I have searched google but i didn't find any example or someone having the same problem.

Any Clues?

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2 Answers

up vote 1 down vote accepted

I Posted the question in Npgsql Development forum , and got my answer.

NpgSqlPoint type is not yet Supported by EF due to Entity Framework Data type Restriction.

Seems they are still working on this one.

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up vote 1 down vote

It looks like NpgsqlPoint makes a PostgreSQL point type. This is not the same as a POINT geometry type used by the PostGIS Extension (e.g., geometry(Point, 4326)).

To make a PostGIS geometry, you will need x, y and srid (spatial reference ID; e.g. see http://spatialreference.org/). These can be used with a ST_MakePoint geometry constructor, and ST_SetSRID to establish the spatial reference. For example, here's a parameterized command:

SELECT ST_SetSRID(ST_MakePoint(:long:, :lat:), 4326)

which assumes a WGS84 coordinate (SRID=4326).

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Yes I am Actually Trying to insert a normal postgres "point" type. When i make the variable "String" and pass "12.5454,41.1215" for example the point gets saved successfully . But then i have problem reading the point as string from Entity Framework which returns just the class name as value. –  Anestis Kivranoglou Jul 15 '13 at 10:58
    
Ok, the postgis tag suggested that you were using PostGIS. –  Mike T Jul 15 '13 at 23:26
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