AppBox升级进行时 - Any与All的用法(Entity Framework)

AppBox 是基于 FineUI 的通用权限管理框架,包括用户管理、职称管理、部门管理、角色管理、角色权限管理等模块。

属于某个角色的用户列表(Any的用法)

使用Subsonic,我们有两种方法获取属于某个角色的用户列表,分别是表关联和子查询。

Subsonic的表关联实现:

// 查询 X_User 表

SqlQuery q = new Select().From<XUser>().InnerJoin(XRoleUser.UserIdColumn, XUser.IdColumn);

q.Where("1").IsEqualTo("1");



// 在用户名称中搜索

string searchText = ttbSearchUser.Text.Trim();

if (!String.IsNullOrEmpty(searchText))

{

	q.And(XUser.NameColumn).ContainsString(searchText);

}



// 过滤选中角色下的所有用户

object[] values = Grid1.DataKeys[Grid1.SelectedRowIndexArray[0]];

int roleId = Convert.ToInt32(values[0]);

q.And(XRoleUser.RoleIdColumn).IsEqualTo(roleId);





// 在查询添加之后,排序和分页之前获取总记录数

// Grid1总共有多少条记录

Grid2.RecordCount = q.GetRecordCount();



// 排列

q.OrderBys.Add(GetSortExpression(Grid2, XUser.Schema));



// 数据库分页

q.Paged(Grid2.PageIndex + 1, Grid2.PageSize);

XUserCollection items = q.ExecuteAsCollection<XUserCollection>();



Grid2.DataSource = items;

Grid2.DataBind();

 

Subsonic的子查询实现:

// 查询 X_User 表

SqlQuery q = new Select().From<XUser>();

q.Where("1").IsEqualTo("1");



// 在用户名称中搜索

string searchText = ttbSearchUser.Text.Trim();

if (!String.IsNullOrEmpty(searchText))

{

	q.And(XUser.NameColumn).ContainsString(searchText);

}



// 过滤选中角色下的所有用户

object[] values = Grid1.DataKeys[Grid1.SelectedRowIndexArray[0]];

int roleId = Convert.ToInt32(values[0]);

SqlQuery subQ = new Select(XRoleUser.UserIdColumn).From<XRoleUser>().Where(XRoleUser.RoleIdColumn).IsEqualTo(roleId);



q.And(XUser.IdColumn).In(subQ);





// 在查询添加之后,排序和分页之前获取总记录数

// Grid1总共有多少条记录

Grid2.RecordCount = q.GetRecordCount();



// 排列

q.OrderBys.Add(GetSortExpression(Grid2, XUser.Schema));



// 数据库分页

q.Paged(Grid2.PageIndex + 1, Grid2.PageSize);

XUserCollection items = q.ExecuteAsCollection<XUserCollection>();



Grid2.DataSource = items;

Grid2.DataBind();

  

使用Entity Framework就不能从数据库的角度思考问题,而应该从实体类之间的关系考虑问题,具体的实现:

IQueryable<User> q = DB.Users;

 

// 在用户名称中搜索

string searchText = ttbSearchUser.Text.Trim();

if (!String.IsNullOrEmpty(searchText))

{

	q = q.Where(u => u.Name.Contains(searchText));

}



// 过滤选中角色下的所有用户

object[] values = Grid1.DataKeys[Grid1.SelectedRowIndexArray[0]];

int roleId = Convert.ToInt32(values[0]);

q = q.Where(u => u.Roles.Any(r => r.ID == roleId));



// 在查询添加之后,排序和分页之前获取总记录数

Grid2.RecordCount = q.Count();



// 排列和分页

q = SortAndPage<User>(q, Grid2);



Grid2.DataSource = q;

Grid2.DataBind();

  

这里用到了 Any 方法,可以这么理解:检索一些用户,只要用户的任意一个角色是roleId就可以。

 

来看下生成的SQL语句:

exec sp_executesql N'SELECT TOP (20) 

[Project2].[ID] AS [ID], 

[Project2].[Name] AS [Name], 

[Project2].[Email] AS [Email], 

[Project2].[Password] AS [Password], 

[Project2].[Enabled] AS [Enabled], 

[Project2].[Gender] AS [Gender], 

[Project2].[ChineseName] AS [ChineseName], 

[Project2].[EnglishName] AS [EnglishName], 

[Project2].[Photo] AS [Photo], 

[Project2].[QQ] AS [QQ], 

[Project2].[CompanyEmail] AS [CompanyEmail], 

[Project2].[OfficePhone] AS [OfficePhone], 

[Project2].[OfficePhoneExt] AS [OfficePhoneExt], 

[Project2].[HomePhone] AS [HomePhone], 

[Project2].[CellPhone] AS [CellPhone], 

[Project2].[Address] AS [Address], 

[Project2].[Remark] AS [Remark], 

[Project2].[IdentityCard] AS [IdentityCard], 

[Project2].[Birthday] AS [Birthday], 

[Project2].[TakeOfficeTime] AS [TakeOfficeTime], 

[Project2].[LastLoginTime] AS [LastLoginTime], 

[Project2].[CreateTime] AS [CreateTime], 

[Project2].[DeptID] AS [DeptID]

FROM ( SELECT [Project2].[ID] AS [ID], [Project2].[Name] AS [Name], [Project2].[Email] AS [Email], [Project2].[Password] AS [Password], [Project2].[Enabled] AS [Enabled], [Project2].[Gender] AS [Gender], [Project2].[ChineseName] AS [ChineseName], [Project2].[EnglishName] AS [EnglishName], [Project2].[Photo] AS [Photo], [Project2].[QQ] AS [QQ], [Project2].[CompanyEmail] AS [CompanyEmail], [Project2].[OfficePhone] AS [OfficePhone], [Project2].[OfficePhoneExt] AS [OfficePhoneExt], [Project2].[HomePhone] AS [HomePhone], [Project2].[CellPhone] AS [CellPhone], [Project2].[Address] AS [Address], [Project2].[Remark] AS [Remark], [Project2].[IdentityCard] AS [IdentityCard], [Project2].[Birthday] AS [Birthday], [Project2].[TakeOfficeTime] AS [TakeOfficeTime], [Project2].[LastLoginTime] AS [LastLoginTime], [Project2].[CreateTime] AS [CreateTime], [Project2].[DeptID] AS [DeptID], row_number() OVER (ORDER BY [Project2].[Name] DESC) AS [row_number]

	FROM ( SELECT 

		[Extent1].[ID] AS [ID], 

		[Extent1].[Name] AS [Name], 

		[Extent1].[Email] AS [Email], 

		[Extent1].[Password] AS [Password], 

		[Extent1].[Enabled] AS [Enabled], 

		[Extent1].[Gender] AS [Gender], 

		[Extent1].[ChineseName] AS [ChineseName], 

		[Extent1].[EnglishName] AS [EnglishName], 

		[Extent1].[Photo] AS [Photo], 

		[Extent1].[QQ] AS [QQ], 

		[Extent1].[CompanyEmail] AS [CompanyEmail], 

		[Extent1].[OfficePhone] AS [OfficePhone], 

		[Extent1].[OfficePhoneExt] AS [OfficePhoneExt], 

		[Extent1].[HomePhone] AS [HomePhone], 

		[Extent1].[CellPhone] AS [CellPhone], 

		[Extent1].[Address] AS [Address], 

		[Extent1].[Remark] AS [Remark], 

		[Extent1].[IdentityCard] AS [IdentityCard], 

		[Extent1].[Birthday] AS [Birthday], 

		[Extent1].[TakeOfficeTime] AS [TakeOfficeTime], 

		[Extent1].[LastLoginTime] AS [LastLoginTime], 

		[Extent1].[CreateTime] AS [CreateTime], 

		[Extent1].[DeptID] AS [DeptID]

		FROM [dbo].[Users] AS [Extent1]

		WHERE (N''admin'' <> [Extent1].[Name]) AND ( EXISTS (SELECT 

			1 AS [C1]

			FROM [dbo].[RoleUsers] AS [Extent2]

			WHERE ([Extent1].[ID] = [Extent2].[UserID]) AND ([Extent2].[RoleID] = @p__linq__0)

		))

	)  AS [Project2]

)  AS [Project2]

WHERE [Project2].[row_number] > 0

ORDER BY [Project2].[Name] DESC',N'@p__linq__0 int',@p__linq__0=1

go

  

EF生成的SQL语句是很复杂,我们来稍微简化一下(为了看清本质,去掉了排序,过滤以及返回字段的个数等):

exec sp_executesql N'SELECT [Project2].[ID] AS [ID], [Project2].[Name] AS [Name], [Project2].[Email] AS [Email], [Project2].[Password] AS [Password]

	FROM ( SELECT 

		[Extent1].[ID] AS [ID], 

		[Extent1].[Name] AS [Name], 

		[Extent1].[Email] AS [Email], 

		[Extent1].[Password] AS [Password]

		FROM [dbo].[Users] AS [Extent1]

		WHERE (N''admin'' <> [Extent1].[Name]) AND ( EXISTS (SELECT 

			1 AS [C1]

			FROM [dbo].[RoleUsers] AS [Extent2]

			WHERE ([Extent1].[ID] = [Extent2].[UserID]) AND ([Extent2].[RoleID] = @p__linq__0)

		))

	)  AS [Project2]',N'@p__linq__0 int',@p__linq__0=1

go

进一步简化:

exec sp_executesql N' SELECT 

		[Extent1].[ID] AS [ID], 

		[Extent1].[Name] AS [Name], 

		[Extent1].[Email] AS [Email], 

		[Extent1].[Password] AS [Password]

		FROM [dbo].[Users] AS [Extent1]

		WHERE (N''admin'' <> [Extent1].[Name]) AND ( EXISTS (SELECT 

			1 AS [C1]

			FROM [dbo].[RoleUsers] AS [Extent2]

			WHERE ([Extent1].[ID] = [Extent2].[UserID]) AND ([Extent2].[RoleID] = @p__linq__0)

		))

	',N'@p__linq__0 int',@p__linq__0=1

go

进一步简化:

SELECT 

		[Users].[ID] AS [ID], 

		[Users].[Name] AS [Name], 

		[Users].[Email] AS [Email], 

		[Users].[Password] AS [Password]

		FROM [dbo].[Users] AS [Users]

		WHERE EXISTS (SELECT 

			1 AS [C1]

			FROM [dbo].[RoleUsers] AS [RoleUsers]

			WHERE ([Users].[ID] = [RoleUsers].[UserID]) AND ([RoleUsers].[RoleID] = 1)

		)

进一步简化:

SELECT 

		ID, 

		Name, 

		Email, 

		Password

		FROM Users

		WHERE EXISTS (SELECT 

			1

			FROM RoleUsers

			WHERE (Users.ID = RoleUsers.UserID) AND (RoleUsers.RoleID = 1)

		)	

  

最终,我们看到了Entity Framework使用子查询和 EXISTS 关键字来完成 Any 的操作。

 

 

当然,如果是我们自己写SQL,可以使用 IN 关键字来达到相同的效果:

SELECT 

		ID, 

		Name, 

		Email, 

		Password

		FROM Users

		WHERE ID IN (SELECT 

			UserID

			FROM RoleUsers

			WHERE (Users.ID = RoleUsers.UserID) AND (RoleUsers.RoleID = 1)

		)	

也可以使用关联查询达到相同的效果:

SELECT 

		ID, 

		Name, 

		Email, 

		Password

		FROM Users 

		INNER JOIN RoleUsers

		ON (Users.ID = RoleUsers.UserID) AND (RoleUsers.RoleID = 1)

  

幸运的是,我么只需要一个 Any 关键字就完成了这个稍微复杂的查询。  

 

不属于某个角色的用户列表(All的用法)

类似的,查询不属于某个角色的用户列表(用来添加用户到某个角色的UI界面中),使用Subsonic也有两种方法,我们只看下子查询的方式:

SqlQuery q = new Select().From<XUser>(); 

q.Where("1").IsEqualTo("1");

 

// 在职务名称中搜索

string searchText = ttbSearchMessage.Text.Trim();

if (!String.IsNullOrEmpty(searchText))

{

    q.And(XUser.NameColumn).ContainsString(searchText);

}

 

// 排除已经属于本角色的用户

int currentRoleId = GetQueryIntValue("id");

SqlQuery subQ = new Select(XRoleUser.UserIdColumn).From<XRoleUser>().Where(XRoleUser.RoleIdColumn).IsEqualTo(currentRoleId);

 

q.And(XUser.IdColumn).NotIn(subQ);

 

// 在查询添加之后,排序和分页之前获取总记录数

Grid1.RecordCount = q.GetRecordCount();

 

// 排列

q.OrderBys.Add(GetSortExpression(Grid1, XUser.Schema));

 

// 数据库分页

q.Paged(Grid1.PageIndex + 1, Grid1.PageSize);

XUserCollection items = q.ExecuteAsCollection<XUserCollection>();

 

 

Grid1.DataSource = items;

Grid1.DataBind();

  

使用Entity Framework,我们只需借助 All 关键字就能简单实现:

IQueryable<User> q = DB.Users;

 

// 在职务名称中搜索

string searchText = ttbSearchMessage.Text.Trim();

if (!String.IsNullOrEmpty(searchText))

{

    q = q.Where(u => u.Name.Contains(searchText));

}

 

// 排除已经属于本角色的用户

int currentRoleId = GetQueryIntValue("id");

q = q.Where(u => u.Roles.All(r => r.ID != currentRoleId));

 

// 在查询添加之后,排序和分页之前获取总记录数

Grid1.RecordCount = q.Count();

 

// 排列和分页

q = SortAndPage<User>(q, Grid1);

 

Grid1.DataSource = q;

Grid1.DataBind();

  

可以简单的理解:检索一些用户,要保证这些用户的所有角色没有一个是currentRoleId。

  

去除分页和排序后,生成的SQL语句为:

exec sp_executesql N'SELECT 

[Extent1].[ID] AS [ID], 

[Extent1].[Name] AS [Name], 

[Extent1].[Email] AS [Email], 

[Extent1].[Password] AS [Password], 

[Extent1].[Enabled] AS [Enabled], 

[Extent1].[Gender] AS [Gender], 

[Extent1].[ChineseName] AS [ChineseName], 

[Extent1].[EnglishName] AS [EnglishName], 

[Extent1].[Photo] AS [Photo], 

[Extent1].[QQ] AS [QQ], 

[Extent1].[CompanyEmail] AS [CompanyEmail], 

[Extent1].[OfficePhone] AS [OfficePhone], 

[Extent1].[OfficePhoneExt] AS [OfficePhoneExt], 

[Extent1].[HomePhone] AS [HomePhone], 

[Extent1].[CellPhone] AS [CellPhone], 

[Extent1].[Address] AS [Address], 

[Extent1].[Remark] AS [Remark], 

[Extent1].[IdentityCard] AS [IdentityCard], 

[Extent1].[Birthday] AS [Birthday], 

[Extent1].[TakeOfficeTime] AS [TakeOfficeTime], 

[Extent1].[LastLoginTime] AS [LastLoginTime], 

[Extent1].[CreateTime] AS [CreateTime], 

[Extent1].[DeptID] AS [DeptID]

FROM [dbo].[Users] AS [Extent1]

WHERE  NOT EXISTS (SELECT 

	1 AS [C1]

	FROM [dbo].[RoleUsers] AS [Extent2]

	WHERE ([Extent1].[ID] = [Extent2].[UserID]) AND (([Extent2].[RoleID] = @p__linq__0) OR (CASE WHEN ([Extent2].[RoleID] <> @p__linq__0) THEN cast(1 as bit) WHEN ([Extent2].[RoleID] = @p__linq__0) THEN cast(0 as bit) END IS NULL))

)',N'@p__linq__0 int',@p__linq__0=1

go

  

最终简化为:

SELECT 

ID, 

Name, 

Email, 

Password

FROM Users

WHERE  NOT EXISTS (SELECT 

	1

	FROM RoleUsers

	WHERE (ID = RoleUsers.UserID) AND ((RoleUsers.RoleID = 1) OR (CASE WHEN (RoleUsers.RoleID <> 1) THEN cast(1 as bit) WHEN (RoleUsers.RoleID = 1) THEN cast(0 as bit) END IS NULL))

)

  

按照我的理解,其中:

CASE WHEN (RoleUsers.RoleID <> 1) THEN cast(1 as bit) WHEN (RoleUsers.RoleID = 1) THEN cast(0 as bit) END IS NULL

类似于下面的判断:

RoleUsers.RoleID  IS NULL

只是不知道为啥会生成这么令人费解的代码。因为如果 RoleUsers.RoleID为NULL的话,既不会走进第一个WHEN,也不会走进第二个WHEN,自然就是NULL IS NULL为true了。

 

下面简单写个SELECT来验证我的想法:

select CASE WHEN (null <> 1) 

					THEN cast(1 as bit) 

					WHEN (null = 1) 

					THEN cast(0 as bit) 

			END 

	

AppBox升级进行时 - Any与All的用法(Entity Framework)  

注意,这个NULL<>1的结果是FALSE,NULL=1的结果也是FALSE,所以最终的结果才是NULL。

再来看一个简单的SELECT查询:

AppBox升级进行时 - Any与All的用法(Entity Framework)

  

 

下载或捐赠AppBox

1. AppBox v2.1 是免费软件,免费提供下载:http://fineui.com/bbs/forum.php?mod=viewthread&tid=3788 

2. AppBox v3.0 是捐赠软件,你可以通过捐赠作者来获取AppBox v3.0的全部源代码(http://fineui.com/donate/)。

 

 

日寇忘我之心不死,同志尚需警惕!纪念九一八。

 

 

 

你可能感兴趣的:(framework)