Ⅰ 基于C#与sql开发的图书管理系统(VS2010,SQL2008)
http://wenku..com/link?url=_KUiS6VLQtrY9IaDCXoIt_gpaLq9Yz-pyF31p490dmIyxwKGYKZfdcS
Ⅱ sql多表联合查询 数据不正确。
SELECTc.phone,d.y,b.b_f,b.b_d
FROMA
LEFTJOINCONA.c_id=C.id
LEFTJOINBONC.id=B.c_id
LEFTJOINDONB.d_id=D.id
Ⅲ 在XPO中怎么通过配置文件来读取数据库链接
xml version="1.0" encoding="utf-8"?><configuration> <appSettings> <add key="ServerType" value="Access" /> <add key="Server" value="" /> <add key="Database" value="E:data.mdb" /> <add key="User" value="" /> <add key="Password" value="" /> </appSettings></configuration>通过AppSettingReader类来获取配置文件中的设置，然后组合一个连接字符串。我们建议你使用Provider类的GetConnectString方法来（在DevExpress.Xpo.DB命名空间）。using System.Configuration;
using DevExpress.Xpo;
private static string GetConnectionString() {
AppSettingsReader config = new AppSettingsReader();
string serverType, server, database, user, password;
serverType = ((string)(config.GetValue("ServerType", typeof(string))));
server = ((string)(config.GetValue("Server", typeof(string))));
database = ((string)(config.GetValue("Database", typeof(string))));
user = ((string)(config.GetValue("User", typeof(string))));
password = ((string)(config.GetValue("Password", typeof(string))));
switch(serverType) {
case "MSSQL":
return DevExpress.Xpo.DB.MSSqlConnectionProvider.GetConnectionString(server, user, password, database);
case "Access":
return DevExpress.Xpo.DB.AccessConnectionProvider.GetConnectionString(database, user, password);
// ... generate connection strings for other providers, e.g. MySql, Firebird, etc. default:
return Session.GetDefaultConnectionString();
}} 在应用程序的入口，连接字符串必须被赋值到DefaultSession对象。