LinQ技术--转
对‘Microsof SQL Server’数据源的‘用于 SQL server 的.NET Framework 数据提供程序’支持。
对‘Microsof SQL Server’数据源的‘用于 OLE DB 的.NET Framework 数据提供程序’不支持。
对‘Microsoft ODBC 数据源‘用于 用于 ODBC 的 .NET Framework 数据提供程序’不支持。
对‘Microsoft Access 数据库文件’数据源的‘用于OLE DB的.NET Framework 数据提供程序’不支持。
即，对SQL Server的专用数据提供程序支持，对OLE DB、ODBC数据提供程序不支持，对Oralce专用属于提供程序未做测试
建议：
因 为Linq to sql 的数据持久方式不能跨数据库平台，因此后台如果是sql server 数据库，可以使用此orm，调用过程最好是‘业务逻辑层’===》‘数据访问层’====》‘此Linq to sql 的orm对象’，这样，如果要跨数据库，则需要重写‘数据访问层’（此数据访问层相当于一个代理），对上面的各层不会产生影响。
1 protected void Page_Load(object sender, EventArgs e)
2 {
3 DataPersonDataContext dc = new DataPersonDataContext();
4 //查询2
5 GridView1.DataSource = from p in dc.Person
6 where p.ID < 100 && p.Name.StartsWith("bei")
7 select new { 编码 = p.ID, 姓名 = p.Name, 电话 = p.Tel };
8 //查询3
9 var varPerson = from p in dc.Person
10 where p.ID < 100 && p.Tel.StartsWith("010")
11 orderby p.Name descending
12 select new { 编码 = p.ID, 姓名 = p.Name, 电话 = p.Tel };
13 GridView1.DataSource = varPerson;
14 //添加
15 Person person1 = new Person();
16 person1.Name = "xianggang";
17 person1.Tel = "00852-11111111";
18 dc.Person.InsertOnSubmit(person1);
19 dc.SubmitChanges();
20 //更新
21 Person person2 = dc.Person.Where(p => p.Name == "xianggang").First();
22 person2.Tel = "00852-11111110";
23 dc.SubmitChanges();
24
25 //删除
26 Person person3 = dc.Person.Where(p => p.Name == "xianggang").First();
27 dc.Person.DeleteOnSubmit(person3);
28 dc.SubmitChanges();
29 //查询1
30 GridView1.DataSource = dc.Person;
31 GridView1.DataBind();
32 }
33 =>
34 返回结果：
35 ID Name Tel
36 1 beijing 010-0000000
37 2 shanghai 021-0000000
38 13 xianggang 00852-11111111
39 14 xianggang 00852-11111111
40 15 xianggang 00852-11111111
41 16 xianggang 00852-11111111
42 =>
43 =>
44 1、创建linq to sql（即DataPerson.dbml文件）：
45 #pragma warning disable 1591
46 //------------------------------------------------------------------------------
47 // <auto-generated>
48 // 此代码由工具生成。
49 // 运行库版本:2.0.50727.1433
50 //
51 // 对此文件的更改可能会导致不正确的行为，并且如果
52 // 重新生成代码，这些更改将会丢失。
53 // </auto-generated>
54 //------------------------------------------------------------------------------
55 using System;
56 using System.Collections.Generic;
57 using System.ComponentModel;
58 using System.Data;
59 using System.Data.Linq;
60 using System.Data.Linq.Mapping;
61 using System.Linq;
62 using System.Linq.Expressions;
63 using System.Reflection;
64 [System.Data.Linq.Mapping.DatabaseAttribute(Name="msdb")]
65 public partial class DataPersonDataContext : System.Data.Linq.DataContext
66 {
67
68 private static System.Data.Linq.Mapping.MappingSource mappingSource = new AttributeMappingSource();
69
70 #region Extensibility Method Definitions
71 partial void OnCreated();
72 partial void InsertPerson(Person instance);
73 partial void UpdatePerson(Person instance);
74 partial void DeletePerson(Person instance);
75 #endregion
76
77 public DataPersonDataContext() :
78 base(global::System.Configuration.ConfigurationManager.ConnectionStrings["msdbConnectionString"].ConnectionString, mappingSource)
79 {
80 OnCreated();
81 }
82
83 public DataPersonDataContext(string connection) :
84 base(connection, mappingSource)
85 {
86 OnCreated();
87 }
88
89 public DataPersonDataContext(System.Data.IDbConnection connection) :
90 base(connection, mappingSource)
91 {
92 OnCreated();
93 }
94
95 public DataPersonDataContext(string connection, System.Data.Linq.Mapping.MappingSource mappingSource) :
96 base(connection, mappingSource)
97 {
98 OnCreated();
99 }
100
101 public DataPersonDataContext(System.Data.IDbConnection connection, System.Data.Linq.Mapping.MappingSource mappingSource) :
102 base(connection, mappingSource)
103 {
104 OnCreated();
105 }
106
107 public System.Data.Linq.Table<Person> Person
108 {
109 get
110 {
111 return this.GetTable<Person>();
112 }
113 }
114 }
115 [Table(Name="dbo.Person")]
116 public partial class Person : INotifyPropertyChanging, INotifyPropertyChanged
117 {
118
119 private static PropertyChangingEventArgs emptyChangingEventArgs = new PropertyChangingEventArgs(String.Empty);
120
121 private int _ID;
122
123 private string _Name;
124
125 private string _Tel;
126
127 #region Extensibility Method Definitions
128 partial void OnLoaded();
129 partial void OnValidate(System.Data.Linq.ChangeAction action);
130 partial void OnCreated();
131 partial void OnIDChanging(int value);
132 partial void OnIDChanged();
133 partial void OnNameChanging(string value);
134 partial void OnNameChanged();
135 partial void OnTelChanging(string value);
136 partial void OnTelChanged();
137 #endregion
138
139 public Person()
140 {
141 OnCreated();
142 }
143
144 [Column(Storage="_ID", AutoSync=AutoSync.OnInsert, DbType="Int NOT NULL IDENTITY", IsPrimaryKey=true, IsDbGenerated=true)]
145 public int ID
146 {
147 get
148 {
149 return this._ID;
150 }
151 set
152 {
153 if ((this._ID != value))
154 {
155 this.OnIDChanging(value);
156 this.SendPropertyChanging();
157 this._ID = value;
158 this.SendPropertyChanged("ID");
159 this.OnIDChanged();
160 }
161 }
162 }
163
164 [Column(Storage="_Name", DbType="NChar(10)")]
165 public string Name
166 {
167 get
168 {
169 return this._Name;
170 }
171 set
172 {
173 if ((this._Name != value))
174 {
175 this.OnNameChanging(value);
176 this.SendPropertyChanging();
177 this._Name = value;
178 this.SendPropertyChanged("Name");
179 this.OnNameChanged();
180 }
181 }
182 }
183
184 [Column(Storage="_Tel", DbType="NChar(20)")]
185 public string Tel
186 {
187 get
188 {
189 return this._Tel;
190 }
191 set
192 {
193 if ((this._Tel != value))
194 {
195 this.OnTelChanging(value);
196 this.SendPropertyChanging();
197 this._Tel = value;
198 this.SendPropertyChanged("Tel");
199 this.OnTelChanged();
200 }
201 }
202 }
203
204 public event PropertyChangingEventHandler PropertyChanging;
205
206 public event PropertyChangedEventHandler PropertyChanged;
207
208 protected virtual void SendPropertyChanging()
209 {
210 if ((this.PropertyChanging != null))
211 {
212 this.PropertyChanging(this, emptyChangingEventArgs);
213 }
214 }
215
216 protected virtual void SendPropertyChanged(String propertyName)
217 {
218 if ((this.PropertyChanged != null))
219 {
220 this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
221 }
222 }
223 }
224 #pragma warning restore 1591
225 3.linq多表查询
226 sql语句
227 select t_friend.userid,friendid,truename,formid
228 from dbo.t_friend left join dbo.t_userinfo
229 on dbo.t_friend.friendid=dbo.t_userinfo.userid
230 where dbo.t_friend.userid=5 and applystate=1
231 linq语句
232 public void bind()
233 {
234 blogdatabaseDataContext dc = new blogdatabaseDataContext();
235 Table<t_userinfo> login = dc.GetTable<t_userinfo>();
236 Table<t_friend> t_f=dc.GetTable<t_friend>();
237 var info = from t in t_f
238 join c in login on t.friendid equals c.userid
239 where( t.userid == 5 && t.applystate == true)
240 select new
241 {
242 t.formid,
243 t.userid,
244 t.friendid,
245 c.truename,
246 c.picture
247 };
248 this.GridView1.DataSource = info;
249 this.GridView1.DataBind();
250 }