SqlServer:

    <add name="DataSource" connectionString="server=****,***;database=***;uid=***;pwd=***;Max Pool size=512;Min Pool size=10;Pooling=true;"
      providerName="System.Data.SqlClient" />

Access
    <add name="DataSource" connectionString="Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|目录/****.mdb"
         providerName="System.Data.OleDb" />

  |DataDirectory|表示程序所运行的目录