public static List <List <string> > DoReader(this string sql, string connStr, ClientType type) { var result = new List <List <string> >(); switch (type) { case ClientType.SqlSever: { result = DbUtility.ExecuteReaderForSqlSever(sql, connStr); } break; case ClientType.Oracle: { result = DbUtility.ExecuteReaderForOracle(sql, connStr); } break; case ClientType.MySql: { result = DbUtility.ExecuteReaderForMySql(sql, connStr); } break; default: { throw new NotSupportedExceptionInCoreException(); } } return(result); }