View pg_type not found - npgsql

Question

Npgsql v3.0.0-beta0001 (Prerelease) was having below issue while opening connection.
NpgsqlConnection conn = new NpgsqlConnection(#"Server=xx.xx.xx.xx;Port=9996;Database=xxx;User Id=xx;Password=xx;CommandTimeout=40;");
conn.Open();
ex {" : View 'pg_type' not found"} System.Exception {Npgsql.NpgsqlException}
StackTrace " at Npgsql.NpgsqlConnector.DoReadSingleMessage(DataRowLoadingMode dataRowLoadingMode, Boolean returnNullForAsyncMessage)\r\n at Npgsql.NpgsqlConnector.ReadSingleMessage(DataRowLoadingMode dataRowLoadingMode, Boolean returnNullForAsyncMessage)\r\n at Npgsql.NpgsqlConnector.SkipUntil(BackendMessageCode stopAt1, BackendMessageCode stopAt2)\r\n at Npgsql.NpgsqlDataReader.SkipUntil(BackendMessageCode stopAt1, BackendMessageCode stopAt2)\r\n at Npgsql.NpgsqlDataReader.NextResultInternal()\r\n at Npgsql.NpgsqlDataReader.NextResult()\r\n at Npgsql.NpgsqlDataReader.Init()\r\n at Npgsql.NpgsqlCommand.Execute(CommandBehavior behavior)\r\n at Npgsql.NpgsqlCommand.ExecuteDbDataReaderInternal(CommandBehavior behavior)\r\n at Npgsql.NpgsqlCommand.ExecuteDbDataReader(CommandBehavior behavior)\r\n at System.Data.Common.DbCommand.ExecuteReader(CommandBehavior behavior)\r\n at Npgsql.NpgsqlCommand.ExecuteReader(CommandBehavior behavior)\r\n at Npgsql.TypeHandlerRegistry.LoadBackendTypes(NpgsqlConnector connector)\r\n at Npgsql.TypeHandlerRegistry.Setup(NpgsqlConnector connector)\r\n at Npgsql.NpgsqlConnector.Open()\r\n at Npgsql.NpgsqlConnectorPool.GetPooledConnector(NpgsqlConnection Connection)\r\n at Npgsql.NpgsqlConnectorPool.RequestConnector(NpgsqlConnection connection)\r\n at Npgsql.NpgsqlConnection.Open()\r\n at Test.Program.MssDenodoUpdate(String ssConnectionName, String ssTableName, TestDenodoUpdate ssUpdateRecord, String ssWhereClause, Int32 ssTimeout, Int32& ssUpdatedRows) in d:\EMRP\EMRP\DenodoConnector\Source\ConsoleApplication2\Program.cs:line 66" string

Answer 1

EntityFramework needs a "maintenance" DB in order to create databases, etc.
Before npgsql version 2.2.5. this maintenance DB was "postgres" but, since then this maintenance DB is "template1", which exists on all PostgreSQL versions.
To make EF work with Denodo you have to create in VDP the dummy database called template1.
Hope this helps!

Answer 2

Virtual DataPort is compatible with the .Net Data Provider for PostgreSQL version 2.0. The recommended versions are 2.0.12, 2.2.0, 2.2.3 and 2.2.7 .
I used .netframework 4.5, npgsql version 2.2.0
string query = "SELECT * FROM car";
string connectionString = "Server=localhost;Port=9996;Username=admin;Password=admin;Database=admin;Timeout=300;CommandTimeout=300";
try
{
using (NpgsqlConnection connection = new NpgsqlConnection(connectionString))
{
connection.Open();
using (NpgsqlCommand command = new NpgsqlCommand(query, connection))
{
using (DbDataReader reader = command.ExecuteReader())
{
int readRows = 0;
Console.WriteLine();
Console.WriteLine("RESULTS:");
while (reader.Read() && readRows < maxRows)
{
for (int col = 0; col < reader.FieldCount; col++)
{
Console.Write(reader.GetName(col) + "=" + reader[col]);
Console.Write(" ");
}
Console.WriteLine();
readRows++;
}
}
}
}
}