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EF CorE执行sql语句

EF model first方式, 你的DB是继承ObjectContext using (MyObjectContext db = new MyObjectContext() ){ string sql = “ select columnA, columnB from TableA where 1 = 1 ”; db.ExecuteStoreQuery(sql).ToList();//TableAObject就是你定义的...

db.Database.SqlQuery(sql).AsQueryable();//这个返回是queryable 返回DataTable要自己写个扩展方法 public static DataTable SqlQueryForDataTatable(this Database db, string sql, SqlParameter[] parameters) { SqlConnection conn = new Sy...

using (MyObjectContext db = new MyObjectContext() ){ string sql = “ select columnA, columnB from TableA where 1 = 1 ”; db.ExecuteStoreQuery(sql).ToList();//TableAObject就是你定义的对象,对象属性就是columnA, columnB}

可以使用ToTraceString()方法得到EF查询所生成的SQL。 using (var context = new TestDBEntities()) { var query = from p in context.Parents where p.Name == "Lingzhi" select p; ObjectQuery parents = query as ObjectQuery; if (parents !...

给你举个例子: static void Main(string[] args) { using (MyDBEntities en = new MyDBEntities()) { var p1 = en.People.First(x => x.Name == "Jim"); Console.WriteLine(p1.Age); var p2 = en.Database.SqlQuery( @"select top 1 * from per...

declare varchar temp(10) select @temp=z from DB:A where ... if(@temp==1) select * from DB:B where... else if(@temp==2) select * from DB:C where... else if(@temp==3) select * from DB:D where... 这个思路应该是这样的,你自己把代...

MyDbContext db = new MyDbContext("test"); #region Find db.BlogAttachments.Find(1); /** * * * [Limit1].[C4] AS [C4], [Limit1].[C5] AS [C5] FROM ( SELECT TOP (2) [UnionAll1].[Id] AS [C1], [UnionAll1].[FileName] AS [C2], CASE WHEN...

性能上,自然是ef要低些。这是毫无疑问的。but,你觉得这点性能损耗和带来的方便快捷那个更重要,就像二八原则

都用了ef了,怎么还拼接sql,如果用了ORM框架了,除非一些特殊的,最好不要用拼接Sql了

oracle 10g的DBMS_XPLAN包中display_cursor函数不同于display函数,display_cursor用于显示SQL语句的真实的执行计划,在大多数情况下, 显示真实的执行计划有助于更好的分析SQL语句的全过程,尤其是运行此SQL语句实时的I/O开销。通过对比预估的I...

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