OleDbConnection，OracleConnection 或者SqlConnection這種連接，直接執(zhí)行sql語句。現(xiàn)在的連接方式執(zhí)行sql語句有了很大的不同，下面先看看簡單的單表的增刪改查操作，然后再看多表的關(guān)聯(lián)查詢，帶參數(shù)查詢等。

一、ADO.NET Entity對單表的增刪改查

有一個表，即在工程中是一個實體user，為了測試方便，所有字段為string型。

1、增加新記錄

增加一條記錄如下：

[csharp]

using (OracleEntities entities = new OracleEntities())

{

User uer = User.CreateUser("id", "name", "age", "1");

entities.User.AddObject(user);

entities.SaveChanges();

using (OracleEntities entities = new OracleEntities())

{

User uer = User.CreateUser("id", "name", "age", "1");

entities.User.AddObject(user);

entities.SaveChanges();

}

2、刪除內(nèi)容

using (OracleEntities entities = new OracleEntities())

{

User user = entities.User.First(a => a.ID.Equals("id"));

entities.DeleteObject(user);

entities.SaveChanges();

}

using (OracleEntities entities = new OracleEntities())

{

User user = entities.User.First(a => a.ID.Equals("id"));

entities.DeleteObject(user);

entities.SaveChanges();

}

3、修改內(nèi)容

using (OracleEntities entities = new OracleEntities())

{

User user = entities.User.First(a => a.User.Equals("id"));

user.Remarks = "修改了內(nèi)容";

entities.SaveChanges();

}

using (OracleEntities entities = new OracleEntities())

{

User user = entities.User.First(a => a.User.Equals("id"));

user.Remarks = "修改了內(nèi)容";

entities.SaveChanges();

}

4、查詢內(nèi)容

(1)實體直接查詢

[/code]

using (OracleEntities entities = new OracleEntities())

{

ObjectQuery result = entities.User;//查詢所有

foreach (User item in result)

{

}

}

using (OracleEntities entities = new OracleEntities())

{

ObjectQuery result = entities.User;//查詢所有

foreach (User item in result)

{

}

}

[/code]

(2)Esql查詢

ObjectQuery result = entities.CreateQuery("select value it? from? OracleEntities.User as it ");

(3)按條件查

var result = entities.User.Where(o => o.id.Equals("id"));

二、關(guān)聯(lián)查詢比如還有個表Other與User外鍵關(guān)聯(lián)。

進行查詢?nèi)缦?#xff1a;

using (OracleEntities entities = new OracleEntities())

{

string esql = "SELECT b.detail FROM OracleEntities.User as a,OracleEntities.Other as b where a.otherid = b.id and a.id='id'";

ObjectQuery query = entities.CreateQuery(esql);

foreach (DbDataRecord r in query)

{

string ss = r["detail"].ToString();

}

}

using (OracleEntities entities = new OracleEntities())

{

string esql = "SELECT b.detail FROM OracleEntities.User as a,OracleEntities.Other as b where a.otherid = b.id and a.id='id'";? www.jb51.net

ObjectQuery query = entities.CreateQuery(esql);

foreach (DbDataRecord r in query)

{

string ss = r["detail"].ToString();

}

}

當然這些都是最基本的用法，因為使用的Linq和ESql，在后面再Linq和ESql的用法里再詳細說明。

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