实例介绍
【实例简介】
【实例截图】
【核心代码】
目录 LINQ to SQL 语句(1)之 Where..........................................................................................................6 Where 操作...............................................................................................................................6 1.简单形式：....................................................................................................................6 2.关系条件形式：............................................................................................................7 3.First()形式： ..................................................................................................................7 LINQ to SQL 语句(2)之 Select/Distinct .............................................................................................8 1.简单用法：............................................................................................................................8 2.匿名类型 形式：..................................................................................................................8 3.条件形式：............................................................................................................................9 4.指定类 型形式：................................................................................................................10 5.筛选形式：..........................................................................................................................10 6.shaped 形式(整形类型)： ..................................................................................................11 7.嵌套类型形式：..................................................................................................................11 8.本地方法调用 形式(LocalMethodCall)：..........................................................................11 9.Distinct 形式： ....................................................................................................................12 LINQ to SQL 语句(3)之 Count/Sum/Min/Max/Avg.........................................................................13 1.简单形式：..........................................................................................................................13 2.带条件形 式：....................................................................................................................14 1.简单形式：..................................................................................................................14 2.映射形式：..................................................................................................................14 3.元素 ：................................................................................................................................15 1.简单形式：..................................................................................................................15 2.映射形式：..................................................................................................................15 3.元素：..................................................................................................................................15 1.简单形式：..................................................................................................................16 2.映射形式：..................................................................................................................16 3.元素：..........................................................................................................................16 LINQ to SQL 语句(4)之 Join ............................................................................................................17 Join 操作符.....................................................................................................................................17 1.一对多关系(1 to Many)：...................................................................................................17 2.多对多关系(Many to Many)：............................................................................................18 3.自联接关系：......................................................................................................................19 1.双向联接(Two way join)： ..........................................................................................19 2.三向联接(There way join)：........................................................................................20 3.左外部联接(Left Outer Join)：....................................................................................21 4.投影的 Let 赋值(Projected let assignment)： ............................................................21 5.组合键(Composite Key)：...........................................................................................22 6.可为 null/不可为 null 的键关系 (Nullable/Nonnullable Key Relationship)：...........23 LINQ to SQL 语句(5)之 Order By.....................................................................................................23 Order By 操作 .........................................................................................................................23 1.简单形式..............................................................................................................................23 2.带条件形式..........................................................................................................................24 3.降序排序..............................................................................................................................24 4.ThenBy..................................................................................................................................24 5.ThenByDescending ...............................................................................................................26 6. 带 GroupBy 形式................................................................................................................26 LINQ to SQL 语句(6)之 Group By/Having .......................................................................................27 Group By/Having 操作符........................................................................................................27 1.简单形式：..........................................................................................................................27 2.Select 匿名类 ：.................................................................................................................28 3.最大 值................................................................................................................................29 4.最小 值................................................................................................................................30 5.平均 值................................................................................................................................30 6.求和......................................................................................................................................30 7.计数......................................................................................................................................31 8.带条件计数..........................................................................................................................31 9.Where 限制..........................................................................................................................32 10.多列(Multiple Columns).....................................................................................................32 11.表达式(Expression)............................................................................................................33 LINQ to SQL 语句(7)之 Exists/In/Any/All/Contains.........................................................................33 Exists/In/Any/All/Contains 操作符 .........................................................................................33 Any ..................................................................................................................................33 1.简单形式：..................................................................................................................33 2.带条件形式：..............................................................................................................34 All ............................................................................................................................................34 Contains ..................................................................................................................................35 1.包含一个对象：..........................................................................................................35 2.包含多个值：..............................................................................................................36 LINQ to SQL 语句(8)之 Concat/Union/Intersect/Except ................................................................36 Concat/Union/Intersect/Except 操作.....................................................................................36 Concat（连接） .....................................................................................................................36 1.简单形式：..................................................................................................................37 2.复 合形式：................................................................................................................37 Union（合并）.......................................................................................................................37 Intersect（相交） ..................................................................................................................38 Except（与非）......................................................................................................................38 LINQ to SQL 语句(9)之 Top/Bottom 和 Paging 和 SqlMethods .....................................................39 Top/Bottom 操作....................................................................................................................39 Take .........................................................................................................................................39 Skip..........................................................................................................................................39 TakeWhile................................................................................................................................40 SkipWhile ................................................................................................................................40 Paging（分页）操作..............................................................................................................40 1.索引..............................................................................................................................40 2.按唯一键排序..............................................................................................................40 SqlMethods 操作....................................................................................................................41 Like ..................................................................................................................................41 已编译查 询操作(Compiled Query)..............................................................................42 LINQ to SQL 语句(10)之 Insert .......................................................................................................42 插入(Insert)1.简单形式..........................................................................................................42 2.一对多 关系........................................................................................................................43 3.多对多关系..........................................................................................................................43 4.使用动态 CUD 重写(Override using Dynamic CUD)............................................................44 LINQ to SQL 语句(11)之 Update.....................................................................................................45 更新(Update) ..........................................................................................................................45 1.简单形式......................................................................................................................45 2.多项更改......................................................................................................................45 LINQ to SQL 语句(12)之 Delete 和使用 Attach..............................................................................46 删除(Delete)1.简单形式.........................................................................................................46 2.一对多关系..........................................................................................................................46 3.推理删除(Inferred Delete)...................................................................................................47 使用 Attach 更新(Update with Attach) ..................................................................................47 LINQ to SQL 语句(13)之开放式并发控制和事务..........................................................................50 Simultaneous Changes 开放式并发控制...............................................................................50 开放式并发(Optimistic Concurrency) ....................................................................................50 1.Implicit（隐式）..........................................................................................................52 2.Explicit（显式）..........................................................................................................52 LINQ to SQL 语句(14)之 Null 语义和 DateTime.............................................................................53 Null 语义.................................................................................................................................53 1.Null...............................................................................................................................53 2.Nullable<T>.HasValue ..................................................................................................54 日期函数.................................................................................................................................54 1.DateTime.Year ..............................................................................................................55 2.DateTime.Month..........................................................................................................55 3.DateTime.Day...............................................................................................................55 LINQ to SQL 语句(15)之 String .......................................................................................................55 字符串（String）...................................................................................................................55 1.字符 串串联(String Concatenation) ...........................................................................56 2.String.Length ................................................................................................................56 3.String.Contains(substring)............................................................................................56 4.String.IndexOf(substring) .............................................................................................56 5.String.StartsWith (prefix) .............................................................................................57 6.String.EndsWith(suffix) ................................................................................................57 7.String.Substring(start) ..................................................................................................57 8.String.Substring (start, length) .....................................................................................57 9.String.ToUpper() ...........................................................................................................58 10.String.ToLower() .........................................................................................................58 11.String.Trim()................................................................................................................58 12.String.Insert(pos, str) .................................................................................................58 13.String.Remove(start) ..................................................................................................59 14.String.Remove(start, length)......................................................................................59 15.String.Replace(find, replace)......................................................................................59 LINQ to SQL 语句(16)之对象标识..................................................................................................60 对象标识.................................................................................................................................60 对象缓存.................................................................................................................................60 LINQ to SQL 语句(17)之对象加载..................................................................................................61 对象加载延迟加载.................................................................................................................61 预先加载：LoadWith 方法...................................................................................................62 LINQ to SQL 语句(18)之运算符转换..............................................................................................63 1.AsEnumerable：将类型转换为泛型 IEnumerable............................................................63 2.ToArray：将序列转换为数组..............................................................................................63 3.ToList：将序列转换为 泛型列表.......................................................................................63 4.ToDictionary：将序 列转化为字典....................................................................................64 LINQ to SQL 语句(19)之 ADO.NET 与 LINQ to SQL.........................................................................64 1.连接......................................................................................................................................65 2.事务......................................................................................................................................65 LINQ to SQL 语句(20)之存储过程..................................................................................................67 1.标量返回..............................................................................................................................67 2.单一结 果集........................................................................................................................68 3.多个可 能形状的单一结果集............................................................................................69 4.多个结果集..........................................................................................................................74 5.带输出参数..........................................................................................................................83 LINQ to SQL 语句(21)之用户定义函数..........................................................................................84 1.在 Select 中使用用户定义的标量函数..............................................................................84 2.在 Where 从句中 使用用户定义的标量函数...................................................................85 3.使用用户定义的表值函数..................................................................................................87 4.以联接方式使用用户定义的表值函数..............................................................................88 LINQ to SQL 语句(22)之 DataContext.............................................................................................89 创建和删除数据库.................................................................................................................89 数据库验证.............................................................................................................................92 数据库更改.............................................................................................................................92 动态查询.................................................................................................................................93 日志.........................................................................................................................................94 LINQ to SQL 语句(23)之动态查询..................................................................................................94 1.Select....................................................................................................................................95 2.Where...................................................................................................................................96 LINQ to SQL 语句(24)之视图..........................................................................................................98 LINQ to SQL 语句(25)之继承........................................................................................................100 1.一般形式....................................................................................................................101 2.OfType 形式...............................................................................................................102 3.IS 形式........................................................................................................................102 4.AS 形式 ......................................................................................................................103 5.Cast 形式....................................................................................................................103 6.UseAsDefault 形式.....................................................................................................104 7.插入新的记录............................................................................................................105
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