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/）。
