网站推广服务好公司排名,网站词库怎么做,开发app流程,网站小程序制作公司现在有两张表#xff0c;结构一模一样#xff0c;我又不想创建两个一模一样的model#xff0c;就想一个model映射到两张表 废话不多说直接上代码
安装依赖包 创建model
namespace oneModelMultiTable.Model
{public class Test{public int id { get; set; }public string…现在有两张表结构一模一样我又不想创建两个一模一样的model就想一个model映射到两张表 废话不多说直接上代码
安装依赖包 创建model
namespace oneModelMultiTable.Model
{public class Test{public int id { get; set; }public string name { get; set; }public string tablename { get; set; }}
}创建DBContext 我们需要使用tablename 动态指定表名因此需要在DBContext中添加这个属性
namespace oneModelMultiTable
{public class DBHelper:DbContext{public DbSetTest testConfigs { get; set; }public string tablename { get; set; }public DBHelper(DbContextOptionsDBHelper options):base(options){}protected override void OnModelCreating(ModelBuilder modelBuilder){modelBuilder.EntityTest(b {b.ToTable(tablename);b.HasKey(p p.id);});base.OnModelCreating(modelBuilder);//modelBuilder.ApplyConfigurationsFromAssembly(this.GetType().Assembly);}}
}
创建DynamicModelCacheKeyFactory 继承IModelCacheKeyFactory
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Infrastructure;
namespace oneModelMultiTable
{public class DynamicModelCacheKeyFactory : IModelCacheKeyFactory{public object Create(DbContext context, bool designTime){object p context is DBHelper dynamicContext? (context.GetType(), dynamicContext.tablename): (object)context.GetType();return p;}}
}依赖注入
builder.Services.AddDbContextDBHelper(options
{options.UseNpgsql(Host192.168.214.133;Port32222;Databasepostgresdb;Usernamepostgresadmin;Passwordadmin123).ReplaceServiceIModelCacheKeyFactory, DynamicModelCacheKeyFactory();
});创建controller
using Microsoft.AspNetCore.Mvc;
using oneModelMultiTable.Model;// For more information on enabling Web API for empty projects, visit https://go.microsoft.com/fwlink/?LinkID397860namespace oneModelMultiTable.Controllers
{[Route(api/[controller]/[action])][ApiController]public class TestController : ControllerBase{public readonly DBHelper dBHelper;public TestController(DBHelper _DBHelper){dBHelper _DBHelper;}// GET: api/TestController[HttpGet]public ListTest Get(string tablename){dBHelper.tablename tablename;return dBHelper.testConfigs.ToList();}}
}
原理 你可能想通过ToTable()方法来更改表名但是我们如何在OnModelCreating方法中更改表名呢?当EF构建模型时它只运行OnModelCreating一次。
对于这个场景我们需要通过使用IModelCacheKeyFactory来更改默认映射它允许我们连接到模型缓存机制以便EF可以根据其属性创建不同的模型。 EF使用IModelCacheKeyFactory为模型生成缓存键。
https://yanxiaodi.medium.com/mapping-the-model-to-multiple-tables-with-entityframework-core-b46bdeed8661
https://medium.com/pawel.gerr/entity-framework-core-changing-database-schema-at-runtime-dcf1211768c6
https://github.com/xdqt/asp.net-core/tree/master/oneModelMultiTable
