Ado. The models and objects in net

First, ADO. The models and objects in net

1, eexcutenonquery------> Implement non-query operation (Increase and deletion)

SQL statement query non-parameterized

            //Connection String            stringConstr =@"server=.; Database=mydatabase;uid=sa;pwd=sa"; //the SQL statement to execute            stringsql ="INSERT INTO MyDataBase (id,name,age,sex) VALUES (1, ' Caocao ', $, ' m ')"; //Create a Connection object            using(SqlConnection conn =NewSqlConnection (CONSTR)) {                //The first form of writing;//Create execution object (Execute SQL statement)//using (SqlCommand cmd = new SqlCommand ())//{                //cmd.                Connection = conn; //cmd.commandtext = SQL; //    //Open Database//Conn.                Open (); //    //returns the number of rows affected//int count = cmd.                ExecuteNonQuery (); //Console.WriteLine ("{0} Line effect", count); //}                //the second method of passing in the constructor is the SQL statement and the connection object                using(SqlCommand cmd =NewSqlCommand (SQL, conn)) {Conn.                    Open (); intCount =cmd.                    ExecuteNonQuery (); Console.WriteLine ("{0} rows affected", Count); }} console.readkey ()

2. Excutescalar Query First line column (return object type)

            //Prompt user to enter user nameConsole.Write ("Enter User Id:"); stringUserName =Console.ReadLine (); //Prompt user to enter passwordConsole.Write ("Enter Password:"); stringUserpwd =Console.ReadLine (); //Connection String            stringConstr =@"server=.; Databae=mydatabase;uid=sa;pwd=sa"; //SQL statements            stringsql =string. Format ("Select COUNT (*) from Users where Username= ' {0} ' and Userpwd={1}", UserName, userpwd); intCount =0; using(SqlConnection conn =NewSqlConnection (CONSTR)) {                using(SqlCommand cmd =NewSqlCommand (SQL, conn)) {Conn.                    Open (); //returns the first line of the column is the object typeCount = (int) cmd.                ExecuteScalar (); }            }            if(Count >0) {Console.WriteLine ("Login Successful"); }            Else{Console.WriteLine ("Logon Failure"); }

3, Executerader read data row by line

            //Connection String            stringConstr =@"server=.; Database=mydatabase;uid=sa;pwd=sa"; //SQL statement queries the data for the entire table (row by line)            stringsql ="SELECT * from Data"; using(SqlConnection conn =NewSqlConnection (CONSTR)) {                using(SqlCommand cmd =NewSqlCommand (SQL, conn)) {Conn.                    Open (); //read data back and forth in one row of dataSqlDataReader reader =cmd.                    ExecuteReader (); using(reader)//reads down one line at a time until it finishes reading{Console.WriteLine ("{0},{1},{2}", reader[0], reader[1], reader[2]); }                     while(Reader. Read ())//iterate through each row of data until it is finished reading{List<string> list =Newlist<string> ();//creates a row of string types per read line                         for(inti =0; I < reader. FieldCount; i++)//iterate through each column of data in each row{list. ADD (Reader[i].                        ToString ()); } Console.WriteLine (string. Join (",", list)); }                }            }

4. SqlDataAdapter reading Data set

  　　　　　　  stringConstr =@"server=.; Database=mydatabase;uid=sa;pwd=sa"; stringsql ="SELECT * Top from Data"; DataSet DS=NewDataSet (); using(SqlDataAdapter adapter =NewSqlDataAdapter (SQL, CONSTR)) {Adapter.            Fill (DS); }            //Take out the data in the dataset//traverse out each table in the DataSet DS             for(inti =0; I < DS. Tables.count; i++) {DataTable dt=ds.                Tables[i]; //traverse each row in the DataTable DT                 for(intj =0; J < dt. Rows.Count; J + +) {DataRow row=dt.                    Rows[i]; List<string> list =Newlist<string>();  for(intK =0; K < row. Itemarray.length; k++) {list. ADD (row. ITEMARRAY[K].                    ToString ()); } Console.WriteLine (string. Join (",", list)); }            }

Ado. The models and objects in net