EntityFramework 4/5/6 中执行自定义SQL语句

参考：http://www.cnblogs.com/chengxiaohui/articles/2092001.html

在EF4（.NET 4）中，我们有了全新的API：ObjectContext.ExecuteStoreCommand(...)和 ObjectContext.ExecuteStoreQuery<T>(...)。从函数名不难知道前者是为了执行某一并无返回集的SQL 命令，例如UPDATE，DELETE操作；后者是执行某一个查询，并可以将返回集转换为某一对象。

今天小试一把，上代码

using (var db = new CentaStaffEntities())
{
//查询 自定义实体
var presons = db.Database.SqlQuery<Person>("SELECT TOP 10 *  FROM [CentaStaff].[CentaStaff].[Staff] WITH(NOLOCK)");
Console.WriteLine(presons.FirstOrDefault().CnName);
Console.WriteLine(presons.Count());

//查询 EF生成的实体
var staffs = db.Database.SqlQuery<Staff>("SELECT TOP 10 *  FROM [CentaStaff].[CentaStaff].[Staff] WITH(NOLOCK)");
Console.WriteLine(staffs.FirstOrDefault().CnName);
Console.WriteLine(staffs.Count());

//多表查询 自定义实体
var tables = db.Database.SqlQuery<Tables>("SELECT TOP 10 SA.[AwardID],S.[StaffID],S.[CnName]  FROM [CentaStaff].[CentaStaff].[Staff] S WITH(NOLOCK) INNER JOIN [CentaStaff].[CentaStaff].[StaffAward]  SA WITH(NOLOCK)  ON S.[StaffID]=SA.[StaffID]");
Console.WriteLine(tables.FirstOrDefault().CnName);
Console.WriteLine(tables.Count());

//修改和添加
//var execute = db.Database.ExecuteSqlCommand("UPDATE Person SET Name = 'Michael' WHERE PersonID = 1");
//if (execute > 0)
//{
//    Console.Write("execute success");
//}

//查询 参数传递
string sql = "SELECT TOP 10 *  FROM [CentaStaff].[CentaStaff].[Staff] WITH(NOLOCK) WHERE 1=1 ";
sql += " AND CnName=@CnName";

List<SqlParameter> sqlparameters = new List<SqlParameter>();
sqlparameters.Add(new SqlParameter("@CnName", "张三"));

var parameters = db.Database.SqlQuery<Staff>(sql, sqlparameters.ToArray());
Console.WriteLine(parameters.FirstOrDefault().CnName);
Console.WriteLine(parameters.Count());
}

//自定义实体类
public class Person
{
public string CnName
{ get; set; }
public string Gender
{ get; set; }
}
//多表查询
public class Tables
{
public Guid AwardID
{ get; set; }
public Guid StaffID
{ get; set; }
public string CnName
{ get; set; }
}

在EF的项目，对于很耗性能的查询语句，采用SQL语句查询，会是一个比较好的选择。