为了适应应对各种数据库间切换，有时需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 。

DBProviderName配置问题

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。