How can I save a variable from a database and use it in C#? -

i changing program , need because don't know c#. change things with:

strsql = "update materials set "; strsql = strsql + "dscr = 'concrete', "; strsql = strsql + "width=50 "; strsql = strsql + " id=385"; objcmd = new oledbcommand(strsql, db_def.conn); objcmd.executenonquery(); 

there case need find id, store , use again. use select

 oledbcommand cmd = new oledbcommand("select id materials    type=1", db_def.conn);  oledbdatareader reader = cmd.executereader();  if (reader.hasrows)  {    reader.read();    var result = reader.getint32(0);  }   strsql = "update materials set ";  strsql = strsql + "dscr = 'concrete', ";  strsql = strsql + "width=50 ";  strsql = strsql + " id=result";  objcmd = new oledbcommand(strsql, db_def.conn);  objcmd.executenonquery(); 

but error:

no value given 1 or more required parameters.

you can try , tell me if works

     oledbcommand cmd = new oledbcommand("select id materials    type=1", db_def.conn);      oledbdatareader reader = cmd.executereader();     int result=-1 ;      if (reader.hasrows)      {        reader.read();        result = reader.getint32(0);      } if (result != -1) {      strsql = "update materials set ";      strsql = strsql + "dscr = 'concrete', ";      strsql = strsql + "width=50 ";      strsql = strsql + " id="+result;      objcmd = new oledbcommand(strsql, db_def.conn);      objcmd.executenonquery(); }