postgresql 首先为代码配置 EF 和 Npgsql
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Configuring EF and Npgsql for code first
提问by Sava B.
I'm trying to get EF to work with Postgresql. I would like code-first migrations if possible. So far, I got a simple ADO command to work, so I'm pretty sure at least my connection string is right. But I can't get EF code migrations to work for the life of me, and I can't find any recent guides that have helped.
我正在尝试让 EF 与 Postgresql 一起工作。如果可能，我希望代码优先迁移。到目前为止，我有一个简单的 ADO 命令可以工作，所以我很确定至少我的连接字符串是正确的。但是我无法让 EF 代码迁移在我的一生中起作用，而且我找不到任何有帮助的最新指南。
I used NuGet to bring in Npgsql, EntityFramework and EntityFramework6.Npgsql. I created an empty database called blogsample in pgadmin.
我使用 NuGet 引入了 Npgsql、EntityFramework 和 EntityFramework6.Npgsql。我在 pgadmin 中创建了一个名为 blogsample 的空数据库。
Currently, When I run the app, it throws on line 29, when I try to add a blog to db:
目前，当我运行该应用程序时，当我尝试将博客添加到 db 时，它会在第 29 行抛出：
An unhandled exception of type 'System.Data.SqlClient.SqlException' occurred in EntityFramework.dll
Additional information: A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)
Here is my .cs file:
这是我的 .cs 文件：
using Npgsql;
using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Data.Entity;
using System.Linq;
namespace NpgSqlTest
{
class Program
{
static void Main(string[] args)
{
EFTest();
}
private static void EFTest()
{
using (var db = new BloggingEntities())
{
// Create and save a new Blog
Console.Write("Enter a name for a new Blog: ");
var name = Console.ReadLine();
var blog = new Blog { Name = name };
db.Blogs.Add(blog);
db.SaveChanges();
// Display all Blogs from the database
var query = from b in db.Blogs
orderby b.Name
select b;
Console.WriteLine("All blogs in the database:");
foreach (var item in query)
{
Console.WriteLine(item.Name);
}
Console.WriteLine("Press any key to exit...");
Console.ReadKey();
}
}
private static void ADOTest()
{
string ConnectionString = ConfigurationManager.ConnectionStrings["PostgresDotNet"].ConnectionString;
using (NpgsqlConnection conn = new NpgsqlConnection(ConnectionString))
{
conn.Open();
const string sql = "SELECT * from sample;";
NpgsqlCommand cmd = new NpgsqlCommand(sql, conn);
DataSet ds = new DataSet();
using (NpgsqlDataAdapter adapter = new NpgsqlDataAdapter(cmd))
{
adapter.Fill(ds);
}
int i = 0;
}
}
}
public class Blog
{
public int BlogId { get; set; }
public string Name { get; set; }
public virtual List<Post> Posts { get; set; }
}
public class Post
{
public int PostId { get; set; }
public string Title { get; set; }
public string Content { get; set; }
public int BlogId { get; set; }
public virtual Blog Blog { get; set; }
}
public class BloggingEntities : DbContext
{
public DbSet<Blog> Blogs { get; set; }
public DbSet<Post> Posts { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
// PostgreSQL uses the public schema by default - not dbo.
modelBuilder.HasDefaultSchema("public");
base.OnModelCreating(modelBuilder);
}
}
}
And my App.config:
还有我的 App.config：
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<configSections>
<!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
<section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
</configSections>
<startup>
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5.2" />
</startup>
<system.data>
<DbProviderFactories>
<!--for EF4.x and EF6.0.x -->
<!--you may need this. if you don't modify machine.config-->
<remove invariant="Npgsql" />
<add name="Npgsql - .Net Data Provider for PostgreSQL" invariant="Npgsql" description=".Net Data Provider for PostgreSQL" type="Npgsql.NpgsqlFactory, Npgsql, Version=3.0.3.0, Culture=neutral, PublicKeyToken=5d8b90d52f46fda7" />
</DbProviderFactories>
</system.data>
<entityFramework>
<providers>
<!--for EF6.0.x -->
<!--you need this. add it manually-->
<provider invariantName="Npgsql" type="Npgsql.NpgsqlServices, EntityFramework6.Npgsql" />
</providers>
</entityFramework>
<connectionStrings>
<add name="PostgresDotNet"
connectionString="User ID=sava;Password=abc;Host=localhost;Port=5432;Database=blogsample;Pooling=true;"
providerName="System.Data.EntityClient" />
</connectionStrings>
</configuration>
回答by Steve Greene
Your context doesn't appear to be using your connection string. Do that with the constructor on your context:
您的上下文似乎没有使用您的连接字符串。在您的上下文中使用构造函数执行此操作：
public class BloggingEntities : DbContext
{
public BloggingEntities()
: base("PostgresDotNet") { }
public DbSet<Blog> Blogs { get; set; }
public DbSet<Post> Posts { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
// PostgreSQL uses the public schema by default - not dbo.
modelBuilder.HasDefaultSchema("public");
base.OnModelCreating(modelBuilder);
}
}
http://fdevel.blogspot.com/2013/12/npgsql-with-entity-framework-6.html
http://fdevel.blogspot.com/2013/12/npgsql-with-entity-framework-6.html
