Code First是Entity Framework提供的一种新的编程模型。通过Code First我们可以在还没有建立数据库的情况下就开始编码,然后通过代码来生成数据库。下面具体讲解一下,在操作的时候可能会出现的错误,
主要分为一下几大步骤,
1. 安装Entity Framework
2. Entity Framework数据库连接配置
<add name="BreakAwayContext" connectionString="data source=.;initial catalog=CodeFirstDemoDB;persist security info=True;user id=sa;password=123456;MultipleActiveResultSets=True;App=EntityFramework" providerName="System.Data.SqlClient" />
3. Entity Framework DbContext连接数据库
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;using System.Data.Entity;
using System.Data.Entity.ModelConfiguration.Conventions;namespace Portal
{
public class PortalContext : DbContext
{
static PortalContext()
{
Database.SetInitializer<PortalContext>(null);
} public PortalContext()
: base("name=PortalContext")
{
// 禁用延迟加载
this.Configuration.LazyLoadingEnabled = false;
} protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
// 禁用默认表名复数形式
modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
// 禁用一对多级联删除
modelBuilder.Conventions.Remove<OneToManyCascadeDeleteConvention>();
// 禁用多对多级联删除
modelBuilder.Conventions.Remove<ManyToManyCascadeDeleteConvention>();
}
}
}
最后 测试一个控制台程序执行完毕后即可插入到数据库中。
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;namespace CodeFirstProject
{
class Program
{
static void Main(string[] args)
{
var d = DateTime.Now.Date.ToString("yyyyMM");
var destination = new Destination
{
Country = "China",
Description = "China Is Friendly",
Name = "Chinese"
};
using (var context = new BreakAwayContext())
{
context.Destinations.Add(destination);
context.SaveChanges();
}
Console.WriteLine("OK");
}
}
}
以上便是最入门的CodeFirst讲解,如有不好的地方还望指教,欢迎留言交流!