首先无法使用Npgsql和Entity Framework代码在PostreSQL中创建数据库

我正在尝试将我的应用程序设置为与PostgreSQL一起使用Entity Framework，但是遇到了一个问题。我已经通过nuget添加了 Npqsql ，并将以下提供程序工厂添加到了 web.config ：

I am attempting to set up my application to use Entity Framework with PostgreSQL, but I have run up against a problem. I have added Npqsql via nuget, and added the following provider factory to web.config:

<system.data>
    <DbProviderFactories>
        <add name="Npgsql Data Provider" 
           invariant="Npgsql" 
           description=".Net Framework Data Provider for Postgresql Server" 
           type="Npgsql.NpgsqlFactory, Npgsql, 
                 Version=2.0.12.0, Culture=neutral, 
                 PublicKeyToken=5d8b90d52f46fda7" />
    </DbProviderFactories>
  </system.data>

使用连接字符串：

    <add name="MyDb" providerName="Npgsql" 
connectionString="Server=localhost;Port=5432;Database=withoomph;User ID=postgres;Password=******;enlist=true" />

似乎可以连接到数据库，但是当我尝试对数据库进行任何操作时DB，我得到以下异常：

It seems to connect to the DB fine, but when I try and do any sort of action on the DB I get the following exception:

FATAL：3D000：数据库 withoomph不存在

按如下所示设置数据库时，我正在正确设置数据库初始化器：

I am setting the database intitializer correctly when the db is set up like so:

static MyDB()
{
    Database.SetInitializer<MyDB>(new CreateDatabaseIfNotExists<MyDB>());
}

因此，当我尝试对 DbContext 对吗？我不明白，整个上午都在梳头！

So it should just simply create db when I try and do anything with my DbContext right? I don't get it, been pulling my hair out all morning!