为了适应应对各种数据库间切换，我们有时想要要自定义写一个通用的SqlHelper。常用的做法就是在
System.Data.Common.DbProviderFactories.GetFactory(dbProviderName).CreateConnection ，来返回对应的 数据库的Connection 。
直接上测试源码：
string dbProviderName = "System.Data.Odbc"; dbProviderName = "System.Data.OleDb"; dbProviderName = "System.Data.SqlClient"; dbProviderName = "System.Data.OracleClient"; //引用 System.Data.SQLite.dll dbProviderName = "System.Data.SQLite"; //引用 MySql.Data.dll dbProviderName = "MySql.Data.MySqlClient"; //引用 Oracle.ManagedDataAccess.dll dbProviderName = "Oracle.ManagedDataAccess.Client"; DbProviderFactory dbfactory = DbProviderFactories.GetFactory(dbProviderName); DbConnection dbconn = dbfactory.CreateConnection; dbconn.ConnectionString = string.Empty;// 数据库连接字符串需要注意的 config 配置：
<?xml version="1.0" encoding="utf-8"?><configuration> <startup useLegacyV2RuntimeActivationPolicy="true"> <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/> <supportedRuntime version="v2.0.50727"/> </startup><system.data> <DbProviderFactories> <remove invariant="System.Data.SQLite"/> <add name="SQLite Data Provider" invariant="System.Data.SQLite" description=".Net Framework Data Provider for SQLite" type="System.Data.SQLite.SQLiteFactory, System.Data.SQLite" /> <remove invariant="MySql.Data.MySqlClient"/> <add name="MySQL Data Provider" invariant="MySql.Data.MySqlClient" description=".Net Framework Data Provider for MySQL" type="MySql.Data.MySqlClient.MySqlClientFactory, MySql.Data" /> <remove invariant="Oracle.ManagedDataAccess.Client"/> <add name="Oracle Data Provider" invariant="Oracle.ManagedDataAccess.Client" description="Oracle Data Provider for .NET" type="Oracle.ManagedDataAccess.Client.OracleClientFactory, Oracle.ManagedDataAccess" /> </DbProviderFactories> </system.data></configuration>最后附上代码。