I'm trying to do ModelFirst (scaffolding) of an existing bbdd in postgresql with geometry data.
In the VS project I have well installed all the necessary nuget packages (EntityFrameworkCore, EntityFrameworkCore.Design, EntityFrameworkCore.Relational, EntityFrameworkCore.Tools, Npgsql.EntityFrameworkCore.PostgreSQL, Npgsql.EntityFrameworkCore.PostgreSQL.Design and Npgsql.NetTopologySuite).
In VS PM, when launching the command:
Scaffold-DbContext "Host=myserver;Database=spatial;Username=postgres;Password=xxxxxxxx" Npgsql.EntityFrameworkCore.PostgreSQL -Schemas spu -OutputDir Spatials
He gives me these exceptions:
Could not find type mapping for column 'spu.nuts.geom' with data type
'geometry(Geometry,4326)'. Skipping column.
And it doesn't map the geometry columns, all rest columns are ok.
What am I doing wrong?
Can I specify scaffolding using NetTopologySuite?
Thanks a lot
Edit: Solved.
Show comments
After much effort getting my MVC5 vb.net app configured with Npgsql and EntityFramework6.Npgsql I can connect to the postgres database fine using the Entity Data Model Wizard in Visual Studio 2017, creating a new connection with Data Provider of PostgreSQL Database, entering my database server details and testing the connection (succeeds). I can also double-click the EDMX file and add tables, etc as expected. This is my first project that talks to a postgreSQL database (normally use MS SQL Server). Everything seems to be happy and fine until I encounter code that is a linq statement that attempts to query the database. My Linq statement is:
Dim l_ListOfPwrCycleCrashEvents As List(Of pwr_cycle_crash_events) = (From item In m_AnalyticsEntities.pwr_cycle_crash_events Where item.serialnumber = "0123445678" Select item).ToList
I have the statement in a try/catch block, but visual studio still reports the following:
Exception thrown:'System.Net.Sockets.SocketException' in System.dll Additional
information: A non-blocking socket operation could not be completed
immediately occurred
I cannot seem to figure out why this statement fails. I am able to use similar statements against a different EntityFramework (MS SQL Server) that is also configured in the application.
The complete method that contains the linq statement:
Public ReadOnly Property iCountOfPwrCycleCrashEvents(
ByVal a_sSerialNumber As String
) As Integer Implements IAnalytics.iCountOfPwrCycleCrashEvents
Get
Try
Dim l_ListOfPwrCycleCrashEvents As List(Of pwr_cycle_crash_events) = (From item In m_AnalyticsEntities.pwr_cycle_crash_events
Where item.serialnumber = a_sSerialNumber
Select item).ToList
If (l_ListOfPwrCycleCrashEvents IsNot Nothing) Then Return l_ListOfPwrCycleCrashEvents.Count
Catch l_Exception2 As System.Net.Sockets.SocketException
Dim askjfhakjh As Integer = 7
Catch l_Exception As Exception
Dim kjhadkjh As Integer = 1
End Try
Return 0
End Get
End Property
I am using Npgsql v4.1.1 and EntityFramework6.Npgsql v6.3.0 in an application that targets .NET Framework 4.5.1.
I can't seem to figure out why the linq statement throws this exception or how to solve the problem. What suggestions do you have?
I figured out the issue. I was using 4.5.1 framework because I thought I had a dependency that would not allow me to move to 4.5.2. I went to Package Manager Console and ran the following command:
Update-Package -ProjectName myProjectName -reinstall
By doing so, I found that I had a package that was needed but could not be loaded because it required the 4.5.2 framework (or higher). I changed the framework of the app to 4.5.2 and issued the above Package Manager command and it executed without errors. I ran the app and the linq statement no longer throws an exception.
WPF PostgreSQL 11.1
Npgsql.PostgresException: '42P01: relation "testme" does not exist'
When attempting to use a PostgreSQL database with multiple schemas, I have defined the following connection strings in the App.config. Note that the only difference is in the SearchPath:
<system.data>
<DbProviderFactories>
<add name="Npgsql Data Provider" invariant="Npgsql" support="FF" description=".Net Framework Data Provider for Postgresql Server" type="Npgsql.NpgsqlFactory, Npgsql, Version=4.0.4.0, Culture=neutral" />
</DbProviderFactories>
</system.data>
<connectionStrings>
<clear />
<add name="localconnection" providerName="Npgsql" connectionString="Server=127.0.0.1;Port=5432;Database=chaos;User Id=postgres;Password=****;Searchpath=nova" />
<add name="phoenixconnection" providerName="Npgsql" connectionString="Server=127.0.0.1;Port=5432;Database=chaos;User Id=postgres;Password=****;SearchPath=phoenix;" />
</connectionStrings>
The Npgsql data provider was installed using NuGet: Runtime Version:
v4.0.30319 Version: 4.0.4.0
In PostgreSQL, in the Phoenix schema:
CREATE TABLE phoenix.testme
(
name text COLLATE pg_catalog."default" NOT NULL
)
WITH (
OIDS = FALSE
)
TABLESPACE pg_default;
ALTER TABLE phoenix.testme
OWNER to postgres;
Using PgAdmin, displaying the testme table works without problem:
select * from phoenix.testme;
I have configured the WCF service using the above connection strings. Using PetaPoco, I write the following script:
public string SayHello()
{
string msg;
using (var db = new chaosDB("phoenixconnection"))
{
var m = db.ExecuteScalar<string>("select version()");
msg = string.Format("Hello from {0}", m);
m = db.ExecuteScalar<string>("select current_schema");
msg = string.Format("{0} Current Schema is {1}", msg, m);
var ss = db.ExecuteScalar<string>("show search_path");
var s = db.Fetch<string>("select * from testme"); <---THIS FAILS!
msg = string.Format("{0} I Am {1}", msg, m);
}
return msg;
}
All works correctly until the "select * from testme" is executed, when I receive the above error. Note: ss from "show search_path" returns correctly with "phoenix"
WHAT AM I DOING WRONG? How do I get this to work??
Any help is most appreciated?
After much head scratching the answer became self-evident. First I had reset the search_path in the database. This did not help. Then I rebuilt the POCO's with PetaPoco and quickly discovered that not only was the new table, "testme", not created, but nor were any POCO's. So, checking, the Database.tt file in PetaPoco showed it to have the wrong ConnectionStringName. Changing the ConnectionStringName to "phoenixconnection" allowed building the POCO's, but again failed to find the "testme" table.
Then the mistake became readily apparent, as stated above, both the "phoenixconnection" and the "localconnection" were pointed to the same port. From previous development, I had PostgreSQL v10.1 running on the same port as the newer PostgreSQL v11.1. Apparently, the first PostgreSQL v10.1 was receiving the connection (and not the newer PostgreSQL v11.1).
Going to services (services.msc) and shutting down v10.1 and running Database.TT now gave the error:
System.InvalidOperationException: Sequence contains more than one matching element
Apparently v10.1 (which I was using for development) only had ONE schema, but v11.1 has multiple schemas. I take the error message to mean that PetaPoco was seeing multiple tables with the same table name--i.e.,it was not distinguishing between schemas.
So, the problem is now solved.
Fix the ports! The older single-schema PostgreSQL v10.1 is kept on port: 5432.
The newer multiple-schema PostgreSQL is kept on port 5433. The v10.1 will be used for the POCO's.
Fix the connection strings in App.config of the WCF so that at run time, the WCF will use the newer v11.1. Once generated, LEAVE THE POCO'S alone and reference them in the WCF file.
Apparently, PetaPoco, can only work with one schema in generating its POCO's, but at runtime will read the connection strings from the App.Config of the WCF to execute its queries, etc. (So in the App.config where Database.TT resides, point PetaPoco to the "development" Database having only a single schema, but in the WCF environment, point the connection string to the new database with multiple schemas. The SearchPath of the connection string IS respected when running through Npgsql).
It would be nice if PetaPoco could generate POCO's specific to a schema in a multi-schema environment, but at the moment, I guess it can't :(
Addendum Note: It turns out that a given instance of PostgreSQL can have multiple DATABASES. So if the connection string for Npgsql is specific to a development database --i.e., a database with only one schema--then during development, PetaPoco works great to create the POCO's. These POCO's can then be directly used in a WCF Service project and uploaded to IIS website. The App.config files of the web site can then be directed to use the run-time database (again in the connection string) to the deployed database. All works well! :)
Why does this code throw an error?
Simple console app in C#, connection string for DbContext is
|DataDirectory|database.sdf
Database is in bin\Debug folder as database.sdf with 9 records. SQL Server Compact 4.0
var localCredential = Db.Credentials
.OrderByDescending(p => p.DateCreated)
.FirstOrDefault();
Error:
Object reference not set to an instance of an object.
Code related info:
Refer to Entity Framework 6.13 by NuGet under Visual Studio 2013
Use database-first mode, that is, create .edmx file with Visual Studio template ADO.NET Entity Data Model -> EF Designer from database
My DbContext code:
public partial class MySampleEntities : DbContext
{
public MySampleEntities ()
{
}
public MySampleEntities (string nameOrConnectionString)
: base(nameOrConnectionString)
{
}
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
throw new UnintentionalCodeFirstException();
}
...
}
One method to modify model with below sample code:
using (var dbContext = GetDbContext())
{
...
dbContext.Entry(blobItem).State = EntityState.Modified;
await dbContext.SaveChangesAsync();
}
Unit Test Cases info:
Use NUnit and Moq
Some Unit Test code:
var mockContext = new Mock<MySampleEntities>();
Test passed with initial database schema, after some database table column names changed, and execute Visual Studio "Update Model from Database..." command on .edmx diagram, update all corresponding model properties, build code, and finally failed to run unit test on code dbContext.Entry(blobItem).State = EntityState.Modified with this exception:
The model backing the 'MySampleEntities' context has changed since the database was created. Consider using Code First Migrations to update the database (http://go.microsoft.com/fwlink/?LinkId=238269).
Solutions tried:
Use Database.SetInitializer(null) in constructors of MySampleEntities
Failed to execute NuGet Package Manager commands like Enable-Migrations, Update-Database etc with below exception, seems it is for code-first mode:
System.Data.Entity.Infrastructure.UnintentionalCodeFirstException: The context is being used in Code First mode with code that was generated from an EDMX file for either Database First or Model First development. This will not work correctly.
My questions:
How to resolve such issue to make unit test case run successfully?