C #-SqlServer connection

C # connecting to a database is not applicable to java in terms of classes. Different databases have different class libraries. Only the connection class of SqlServer is used here.

Public class DbLink {private string config = ConfigurationManager. connectionStrings ["SqlConnection"]. connectionString; // you can directly write the connection string private SqlConnection con; private OracleConnection oracon; private SqlCommand com; private SqlTransaction sqlTra; public DbLink () {con = new SqlConnection (config ); con. open (); com = new SqlCommand (); com. connection = con;} // data retrieval public SqlDataReader select (string SQL) {com. commandText = SQL; SqlDataReader sdr = com. executeReader (); return sdr;} // retrieve public int selectCount (string SQL) {com. commandText = SQL; int count = (int) com. executeScalar (); return count;} // data update/Add/delete public int update (string SQL) {com. commandText = SQL; int num = com. executeNonQuery (); return num;} // enable the public void beginTransaction () {sqlTra = con. beginTransaction (); com. transaction = sqlTra;} // Transaction commit public void commit () {sqlTra. commit () ;}// transaction rollback public void rollback () {sqlTra. rollback ();}}

The connection string is configured in web. config.

  <connectionStrings>    <add name="SqlConnection" connectionString="server=.;database=Temp;uid=sa;pwd=123" providerName="System.Data.SqlClient"/>  </connectionStrings>