我试图让EF 5.0 code第一次使用的PostgreSQL(Npgsql提供商)。我有Npgsql 2.0.12.1通过的NuGet安装(引用的程序集是2.0.12.0虽然)。 我有Npgsql中的app.config声明(包括默认连接工厂和供应商的工厂):
I'm trying to get EF 5.0 code first working with PostgreSQL (Npgsql provider). I have Npgsql 2.0.12.1 installed via NuGet (referenced assembly is 2.0.12.0 though). I have Npgsql declared in app.config (both default connection factory and provider factory):
<entityFramework> <defaultConnectionFactory type="Npgsql.NpgsqlFactory, Npgsql, Version=2.0.12.0, Culture=neutral, PublicKeyToken=5d8b90d52f46fda7" /> </entityFramework> <system.data> <DbProviderFactories> <add name="Npgsql Data Provider" invariant="Npgsql" description="Data Provider for PostgreSQL" support="FF" type="Npgsql.NpgsqlFactory, Npgsql, Version=2.0.12.0, Culture=neutral, PublicKeyToken=5d8b90d52f46fda7"/> </DbProviderFactories> </system.data>
我有以下的测试运行成功:
I have following test running successfully :
[Test] public void DatabaseConnection_DatabaseFactoryTest() { var factory = DbProviderFactories.GetFactory("Npgsql"); var conn = factory.CreateConnection(); conn.ConnectionString = _connectionString; var npg = (NpgsqlConnection)conn; var result = TestConnectionHelper(npg); // scalar select version(), nothing particular Assert.AreEqual(result, "PostgreSQL 9.2.2, compiled by Visual C++ build 1600, 64-bit"); }这意味着至少有数据库实例运行,并提供配置成功。 现在,我想是使用自定义的数据库上下文从的DbContext继承,将通过连接字符串来连接到相同的提供者和初始化的:
That means at least database instance is running and provider is configured successfully. Now what i want is to use custom database context inherited from DbContext which will be tied to same provider and initialized via connection string :
public class InventoryContext : DbContext { public InventoryContext(string nameOrConnectionString) : base(nameOrConnectionString) { } // mappings and properties, cut for conciseness }
下面的测试失败:
Following test fails :
[Test] public void DatabaseConnection_DatabaseContextTest() { using (var ctx = new InventoryContext(_connectionString)) { //var db = ctx.Database; ctx.InventoryObjects.Add(_inventoryObject); // exception here ctx.SaveChanges(); } }
报告说,
Failed to set Database.DefaultConnectionFactory to an instance of the 'Npgsql.NpgsqlFactory, Npgsql, Version=2.0.12.0, Culture=neutral, PublicKeyToken=5d8b90d52f46fda7' type as specified in the application configuration. See inner exception for details.
内部异常是出现InvalidOperationException:
Inner exception is InvalidOperationException :
{"Constructor for type \"Npgsql.NpgsqlFactory\" is not found."}
我想有一个与连接字符串的问题(不包含Npgsql提供商):
I guess there is a problem with connection string (it does not contain Npgsql provider) :
"Server=127.0.0.1;Port=5432;User Id=postgres;Password=p4ssw0rd;Database=InventoryDatabase;";
什么是最优雅的方式以编程方式解决这个问题?刚试过路过的connectionString从app.config中上下文的构造,它的工作原理。 修改 上传的测试项目,Dropbox的 - VS2012的解决方案,10 MB
What is the most elegant way to solve this problem programmatically? Just tried passing connectionString from app.config to context's constructor, it works. edit Uploaded test project to Dropbox - VS2012 solution, 10 mb
推荐答案更深入地挖掘问题,发现它是由这一事实,Npgsql所引用的EntityFramework 4.4.0组装。解决如下:
Dug deeper into the problem, found out that it is caused by that fact that Npgsql is referencing EntityFramework 4.4.0 assembly. Solved as follows :
修正了以下错误的的无法投NpgsqlFactory到IDbConnectionFactory的通过实现IDbConnectionFactory接口NpgsqlFactory:
Fixed following error "Unable cast NpgsqlFactory to IDbConnectionFactory" by implementing IDbConnectionFactory interface on NpgsqlFactory :
使用System.Data.Entity.Infrastructure; ... 公共密封类NpgsqlFactory:DbProviderFactory,IServiceProvider的,IDbConnectionFactory ... 公众的DbConnection创建连接(字符串nameOrConnectionString) { 返回新NpgsqlConnection(nameOrConnectionString); } ð
using System.Data.Entity.Infrastructure; ... public sealed class NpgsqlFactory : DbProviderFactory, IServiceProvider, IDbConnectionFactory ... public DbConnection CreateConnection(string nameOrConnectionString) { return new NpgsqlConnection(nameOrConnectionString); } d
现在我遇到错误:3F000:模式DBO不存在,这是关系到EF。 (表名,大众),虽然modelBuilder.Entity()ToTable:我已经映射到PostgreSQL标准的公共架构中的DbContext的OnModelCreating。期待这个问题的解决方案。
Now i'm experiencing "Error: 3F000: schema "dbo" doesn't exist" which is related to EF. I have mapping to PostgreSQL standard public schema in DbContext's OnModelCreating : modelBuilder.Entity().ToTable("TableName", "public") though. Looking forward to solution of this problem.
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