AppBox升级进行时 - 关联表查询与更新（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。

关联表的查询操作

使用 Include 方法，我们可以在一次数据库查询中将关联表的数据一并取出。

比如查询在线用户列表页面，需要在前端显示关联的用户信息，如下所示：

<x:Grid ID="Grid1" runat="server" BoxFlex="1" ShowBorder="true" ShowHeader="false"
	EnableCheckBoxSelect="false" EnableRowNumber="true" DataKeyNames="ID" AllowSorting="true"
	OnSort="Grid1_Sort" SortColumnIndex="0" SortDirection="DESC" AllowPaging="true"
	IsDatabasePaging="true" OnPageIndexChange="Grid1_PageIndexChange">
	<Columns>
		<x:BoundField DataField="UpdateTime" SortField="UpdateTime" DataFormatString="{0:yyyy-MM-dd HH:mm}"
			Width="120px" HeaderText="最后操作时间" />
		<x:BoundField DataField="LoginTime" SortField="LoginTime" Width="120px" DataFormatString="{0:yyyy-MM-dd HH:mm}"
			HeaderText="登录时间" />
		<x:BoundField DataField="User.Name" SortField="User.Name" Width="100px" HeaderText="用户名" />
		<x:BoundField DataField="User.ChineseName" SortField="User.ChineseName" Width="100px" HeaderText="中文名" />
		<x:BoundField DataField="IPAdddress" ExpandUnusedSpace="true" HeaderText="IP地址" />
		<x:WindowField Text="查看" Title="查看" WindowID="Window1" DataIFrameUrlFields="User.ID"
			DataIFrameUrlFormatString="~/admin/user_view.aspx?id={0}" Width="50px" />
	</Columns>
</x:Grid>

其中“用户名”和“中文名”以及“查看”按钮，都用到了导航属性User（Navigation Property），所以我们在查询时也使用Include来避免延迟加载：

IQueryable<Online> q = DB.Onlines.Include(o => o.User);

// 在用户名中搜索
string searchText = ttbSearchMessage.Text.Trim();
if (!String.IsNullOrEmpty(searchText))
{
	q = q.Where(o => o.User.Name.Contains(searchText));
}

DateTime lastD = DateTime.Now.AddHours(-2);
q = q.Where(o => o.UpdateTime > lastD);

// 在添加条件之后，排序和分页之前获取总记录数
Grid1.RecordCount = q.Count();

// 排列和数据库分页
q = SortAndPage<Online>(q, Grid1);

Grid1.DataSource = q;
Grid1.DataBind();

　　

为了更形象的说明 Include 的作用，我们使用工具ExpressProfile来监视对数据库的操作：http://expressprofiler.codeplex.com/　　

首先看下页面显示效果：

使用 Include 情况下，看下对数据库的操作：

可以看到有两次数据库查询（获取总记录数查询和分页数据查询），相应的查询语句分别为：

获取总记录数的SQL查询语句：

exec sp_executesql N'SELECT
[GroupBy1].[A1] AS [C1]
FROM ( SELECT
	COUNT(1) AS [A1]
	FROM [dbo].[Onlines] AS [Extent1]
	WHERE [Extent1].[UpdateTime] > @p__linq__0
)  AS [GroupBy1]',N'@p__linq__0 datetime2(7)',@p__linq__0='2013-08-23 15:35:08.2573160'
go

分页数据查询的SQL语句：

exec sp_executesql N'SELECT TOP (20)
[Project1].[ID] AS [ID],
[Project1].[IPAdddress] AS [IPAdddress],
[Project1].[LoginTime] AS [LoginTime],
[Project1].[UpdateTime] AS [UpdateTime],
[Project1].[ID1] AS [ID1],
[Project1].[Name] AS [Name],
[Project1].[Email] AS [Email],
[Project1].[Password] AS [Password],
[Project1].[Enabled] AS [Enabled],
[Project1].[Gender] AS [Gender],
[Project1].[ChineseName] AS [ChineseName],
[Project1].[EnglishName] AS [EnglishName],
[Project1].[Photo] AS [Photo],
[Project1].[QQ] AS [QQ],
[Project1].[CompanyEmail] AS [CompanyEmail],
[Project1].[OfficePhone] AS [OfficePhone],
[Project1].[OfficePhoneExt] AS [OfficePhoneExt],
[Project1].[HomePhone] AS [HomePhone],
[Project1].[CellPhone] AS [CellPhone],
[Project1].[Address] AS [Address],
[Project1].[Remark] AS [Remark],
[Project1].[IdentityCard] AS [IdentityCard],
[Project1].[Birthday] AS [Birthday],
[Project1].[TakeOfficeTime] AS [TakeOfficeTime],
[Project1].[LastLoginTime] AS [LastLoginTime],
[Project1].[CreateTime] AS [CreateTime],
[Project1].[DeptID] AS [DeptID]
FROM ( SELECT [Project1].[ID] AS [ID], [Project1].[IPAdddress] AS [IPAdddress], [Project1].[LoginTime] AS [LoginTime], [Project1].[UpdateTime] AS [UpdateTime], [Project1].[ID1] AS [ID1], [Project1].[Name] AS [Name], [Project1].[Email] AS [Email], [Project1].[Password] AS [Password], [Project1].[Enabled] AS [Enabled], [Project1].[Gender] AS [Gender], [Project1].[ChineseName] AS [ChineseName], [Project1].[EnglishName] AS [EnglishName], [Project1].[Photo] AS [Photo], [Project1].[QQ] AS [QQ], [Project1].[CompanyEmail] AS [CompanyEmail], [Project1].[OfficePhone] AS [OfficePhone], [Project1].[OfficePhoneExt] AS [OfficePhoneExt], [Project1].[HomePhone] AS [HomePhone], [Project1].[CellPhone] AS [CellPhone], [Project1].[Address] AS [Address], [Project1].[Remark] AS [Remark], [Project1].[IdentityCard] AS [IdentityCard], [Project1].[Birthday] AS [Birthday], [Project1].[TakeOfficeTime] AS [TakeOfficeTime], [Project1].[LastLoginTime] AS [LastLoginTime], [Project1].[CreateTime] AS [CreateTime], [Project1].[DeptID] AS [DeptID], row_number() OVER (ORDER BY [Project1].[UpdateTime] DESC) AS [row_number]
	FROM ( SELECT
		[Extent1].[ID] AS [ID],
		[Extent1].[IPAdddress] AS [IPAdddress],
		[Extent1].[LoginTime] AS [LoginTime],
		[Extent1].[UpdateTime] AS [UpdateTime],
		[Extent2].[ID] AS [ID1],
		[Extent2].[Name] AS [Name],
		[Extent2].[Email] AS [Email],
		[Extent2].[Password] AS [Password],
		[Extent2].[Enabled] AS [Enabled],
		[Extent2].[Gender] AS [Gender],
		[Extent2].[ChineseName] AS [ChineseName],
		[Extent2].[EnglishName] AS [EnglishName],
		[Extent2].[Photo] AS [Photo],
		[Extent2].[QQ] AS [QQ],
		[Extent2].[CompanyEmail] AS [CompanyEmail],
		[Extent2].[OfficePhone] AS [OfficePhone],
		[Extent2].[OfficePhoneExt] AS [OfficePhoneExt],
		[Extent2].[HomePhone] AS [HomePhone],
		[Extent2].[CellPhone] AS [CellPhone],
		[Extent2].[Address] AS [Address],
		[Extent2].[Remark] AS [Remark],
		[Extent2].[IdentityCard] AS [IdentityCard],
		[Extent2].[Birthday] AS [Birthday],
		[Extent2].[TakeOfficeTime] AS [TakeOfficeTime],
		[Extent2].[LastLoginTime] AS [LastLoginTime],
		[Extent2].[CreateTime] AS [CreateTime],
		[Extent2].[DeptID] AS [DeptID]
		FROM  [dbo].[Onlines] AS [Extent1]
		INNER JOIN [dbo].[Users] AS [Extent2] ON [Extent1].[UserID] = [Extent2].[ID]
		WHERE [Extent1].[UpdateTime] > @p__linq__0
	)  AS [Project1]
)  AS [Project1]
WHERE [Project1].[row_number] > 0
ORDER BY [Project1].[UpdateTime] DESC',N'@p__linq__0 datetime2(7)',@p__linq__0='2013-08-23 15:35:08.2573160'
go

Entity Framework生成的SQL语句包含了子查询和关联查询，还是蛮复杂的。

我们把这两条SQL语句分别在VS2012的服务器资源管理器中执行一下，就能看到和页面上相同的结果了：　　

　　

作为对比，来看下不使用 Include 的数据库SQL查询语句：

此时，除了获取总记录数的SQL查询和获取分页数据的SQL查询，还多了 3 条获取用户信息的SQL查询，其中一个获取用户信息的SQL语句为：

exec sp_executesql N'SELECT
[Extent2].[ID] AS [ID],
[Extent2].[Name] AS [Name],
[Extent2].[Email] AS [Email],
[Extent2].[Password] AS [Password],
[Extent2].[Enabled] AS [Enabled],
[Extent2].[Gender] AS [Gender],
[Extent2].[ChineseName] AS [ChineseName],
[Extent2].[EnglishName] AS [EnglishName],
[Extent2].[Photo] AS [Photo],
[Extent2].[QQ] AS [QQ],
[Extent2].[CompanyEmail] AS [CompanyEmail],
[Extent2].[OfficePhone] AS [OfficePhone],
[Extent2].[OfficePhoneExt] AS [OfficePhoneExt],
[Extent2].[HomePhone] AS [HomePhone],
[Extent2].[CellPhone] AS [CellPhone],
[Extent2].[Address] AS [Address],
[Extent2].[Remark] AS [Remark],
[Extent2].[IdentityCard] AS [IdentityCard],
[Extent2].[Birthday] AS [Birthday],
[Extent2].[TakeOfficeTime] AS [TakeOfficeTime],
[Extent2].[LastLoginTime] AS [LastLoginTime],
[Extent2].[CreateTime] AS [CreateTime],
[Extent2].[DeptID] AS [DeptID]
FROM  [dbo].[Onlines] AS [Extent1]
INNER JOIN [dbo].[Users] AS [Extent2] ON [Extent1].[UserID] = [Extent2].[ID]
WHERE [Extent1].[ID] = @EntityKeyValue1',N'@EntityKeyValue1 int',@EntityKeyValue1=2
go

其在VS2012中的执行结果为：

　　

关联表的新增操作

在前面的文章中，我们已经看到如何新增一个用户，并为用户添加角色列表，如下所示：

User item = new User();
item.Name = tbxName.Text.Trim();
item.Password = PasswordUtil.CreateDbPassword(tbxPassword.Text.Trim());
item.ChineseName = tbxRealName.Text.Trim();
item.Gender = ddlGender.SelectedValue;
item.CompanyEmail = tbxCompanyEmail.Text.Trim();
item.Email = tbxEmail.Text.Trim();
item.OfficePhone = tbxOfficePhone.Text.Trim();
item.OfficePhoneExt = tbxOfficePhoneExt.Text.Trim();
item.HomePhone = tbxHomePhone.Text.Trim();
item.CellPhone = tbxCellPhone.Text.Trim();
item.Remark = tbxRemark.Text.Trim();
item.Enabled = cbxEnabled.Checked;
item.CreateTime = DateTime.Now;

// 添加所有角色
if (!String.IsNullOrEmpty(hfSelectedRole.Text))
{
    int[] roleIDs = StringUtil.GetIntArrayFromString(hfSelectedRole.Text);

    item.Roles = new List<Role>();
    foreach (int roleID in roleIDs)
    {
        Role role = new Role { ID = roleID };
        DB.Roles.Attach(role);
        item.Roles.Add(role);
    }
}

DB.Users.Add(item);
DB.SaveChanges();

　　

关联表的删除操作

从角色中删除多个用户的操作，用Subsonic来实现的代码：

List<int> roleIds = GetSelectedDataKeyIDs(Grid1);
List<int> userIds = GetSelectedDataKeyIDs(Grid2);

new Delete().From<XRoleUser>()
	.Where(XRoleUser.RoleIdColumn).IsEqualTo(roleIds[0])
	.And(XRoleUser.UserIdColumn).In(userIds)
	.Execute();

使用Entity Framework时，由于需要先将需要的数据载入，所以代码稍微有点复杂：

Role role = DB.Roles.Include(r => r.Users)
	.Where(r => r.ID == roleID)
	.FirstOrDefault();

foreach (int userID in userIDs)
{
	User user = role.Users.Where(u => u.ID == userID).FirstOrDefault();
	if (user != null)
	{
		role.Users.Remove(user);
	}
}

DB.SaveChanges();

上面代码也可以简化为：

Role role = DB.Roles.Include(r => r.Users)
	.Where(r => r.ID == roleID)
	.FirstOrDefault();

role.Users.Where(u => userIDs.Contains(u.ID)).ToList().ForEach(u => role.Users.Remove(u));

DB.SaveChanges();

　　

下面再来看看如果移除属于某个部门的多个用户，由于部门和用户是一对多的关系，所以我们可以先找到这些用户，再清空这些用户所属的部门，如下所示：

DB.Users.Include(u => u.Dept)
	.Where(u => userIDs.Contains(u.ID))
	.ToList()
	.ForEach(u => u.Dept = null);

DB.SaveChanges();

另一种做法，先找到这个部门，然后从部门的用户列表Users（导航属性）中删除这些用户，如下所示：

Dept dept = DB.Depts.Include(d => d.Users)
	.Where(d => d.ID == deptID)
	.FirstOrDefault();

foreach (int userID in userIDs)
{
	User user = dept.Users.Where(u => u.ID == userID).FirstOrDefault();
	if (user != null)
	{
		dept.Users.Remove(user);
	}
}

DB.SaveChanges();

上面两种做法的结果是完全一致的。　　

关联表的更新操作

以更新单个用户信息为例，一个用户可以属于一个部门（Dept） ，可以拥有多个角色（Role），使用Subsonic更新用户信息的代码如下所示：

using (TransactionScope scope = new TransactionScope())
{
    int userId = GetQueryIntValue("id");
    XUser item = XUser.FetchByID(userId);
    //item.Name = tbxName.Text.Trim();
    item.ChineseName = tbxRealName.Text.Trim();
    item.Gender = ddlGender.SelectedValue;
    item.CompanyEmail = tbxEmail.Text.Trim();
    item.PersonalEmail = tbxPersonalEmail.Text.Trim();
    item.CellPhone = tbxCellPhone.Text.Trim();
    item.OfficePhone = tbxOfficePhone.Text.Trim();
    item.OfficePhoneExt = tbxOfficePhoneExt.Text.Trim();
    item.HomePhone = tbxHomePhone.Text.Trim();
    item.Remark = tbxRemark.Text.Trim();
    item.Enabled = cbxEnabled.Checked;
    //item.RoleId = Convert.ToInt32(ddlRole.SelectedValue);
    //item.DeptId = Convert.ToInt32(ddlDept.SelectedValue);
    item.Save();

    // 删除用户所属的所有角色
    new Delete().From(XRoleUser.Schema)
        .Where(XRoleUser.UserIdColumn).IsEqualTo(userId)
        .Execute();

    // 添加所有角色
    if (!String.IsNullOrEmpty(hfSelectedRole.Text))
    {
        XRoleUserCollection roleUsers = new XRoleUserCollection();
        foreach (string roleIdStr in hfSelectedRole.Text.Split(','))
        {
            int id = Convert.ToInt32(roleIdStr);

            XRoleUser roleUser = new XRoleUser();
            roleUser.RoleId = id;
            roleUser.UserId = userId;

            roleUsers.Add(roleUser);
        }
        roleUsers.SaveAll();
    }

    // 删除用户所属的所有部门
    new Delete().From(XDeptUser.Schema)
        .Where(XDeptUser.UserIdColumn).IsEqualTo(userId)
        .Execute();

    // 添加所有部门
    if (!String.IsNullOrEmpty(hfSelectedDept.Text))
    {
        XDeptUser deptUser = new XDeptUser();
        deptUser.DeptId = Convert.ToInt32(hfSelectedDept.Text);
        deptUser.UserId = userId;
        deptUser.Save();
    }

    scope.Complete();
}

这里的数据库查询比较多，分别为：

1. 查询单个数据的信息；

2. 删除用户所属的所有角色；

3. 添加用户的新角色；

4. 删除用户所属的部门；

5. 添加用户所属的新部门；（这个地方是数据库设计也不大合理，其实不需单独表来保存部门用户信息）　　

完成相同的功能，来看下Entity Framework的实现：

int id = GetQueryIntValue("id");
User item = DB.Users
    .Include(u => u.Dept)
    .Include(u => u.Roles)
    .Where(u => u.UserID == id).FirstOrDefault();
//item.Name = tbxName.Text.Trim();
item.ChineseName = tbxRealName.Text.Trim();
item.Gender = ddlGender.SelectedValue;
item.CompanyEmail = tbxCompanyEmail.Text.Trim();
item.Email = tbxEmail.Text.Trim();
item.CellPhone = tbxCellPhone.Text.Trim();
item.OfficePhone = tbxOfficePhone.Text.Trim();
item.OfficePhoneExt = tbxOfficePhoneExt.Text.Trim();
item.HomePhone = tbxHomePhone.Text.Trim();
item.Remark = tbxRemark.Text.Trim();
item.Enabled = cbxEnabled.Checked;

if (String.IsNullOrEmpty(hfSelectedDept.Text))
{
    item.Dept = null;
}
else
{
    int newDeptID = Convert.ToInt32(hfSelectedDept.Text);
    if (item.Dept.DeptID != newDeptID)
    {
        Dept newDept = new Dept { DeptID = newDeptID };
        DB.Depts.Attach(newDept);
        item.Dept = newDept;
    }
}

if (String.IsNullOrEmpty(hfSelectedRole.Text))
{
    item.Roles = null;
}
else
{
    int[] roleIDs = StringUtil.GetIntArrayFromString(hfSelectedRole.Text);

    int[] addRoleIDs = roleIDs.Except(item.Roles.Select(r => r.RoleID)).ToArray();
    int[] removeRoleIDs = item.Roles.Select(r => r.RoleID).Except(roleIDs).ToArray();

    foreach (int roleID in addRoleIDs)
    {
        var role = new Role { RoleID = roleID };
        DB.Roles.Attach(role);
        item.Roles.Add(role);
    }
    foreach (int roleID in removeRoleIDs)
    {
        item.Roles.Remove(item.Roles.Single(r => r.RoleID == roleID));
    }

}

DB.SaveChanges();

　　

这里，我们又再次用到了 Attach 方法，实际上这样使用 Attach 是有风险的，下一节我们会重点讲解 Attach 的使用。

下载或捐赠AppBox

1. AppBox v2.0 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/）。