How to increment or add the values in database from front end?

Question

Hello I am Chetan I am a student Currently I am doing GNIIT(Software Engineering) course from NIIT in Pune. Now I am learning ASP.Net. We have told to create a project on Ticket Booking. In which I have to accept value from user store it in database and then increment that value by the next value.Means If I am booking the tickets and I have 100 tickets & I sold 10 tickets of them & that will be get stored in database in a particular row & then if I sold another 5 tickets then it should show me the value that how much tickets I have sold & how much tickets I have still left. Means I want to increment the ticket value by adding the new ticket value in the previous value & that addition will get displayed to the user. Hope you would have understand my problem. I am waiting for your hopeful reply Chetan.

Kirtan Patel · Answer

Assumes that you have table Called Ticket having Two Fields TransactionID Qnt and What you Update Ticket Quantity As like below Screen shot When Clicked Sell button you want to Increase Qnt Field I have created ShowData Function to Show updated Records in grid after updating Values in Database When you click the sell button it First Fecth the last Inserted TrasactionID and updates the Record if you can not Upderstand the code Download the Project Files i Have included private void Form1_Load(object sender EventArgs e) { ShowData(); } public void ShowData() { SqlConnection con = new SqlConnection(@Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\Database1.mdf;Integrated Security=True;User Instance=True); con.Open(); SqlCommand comm = new SqlCommand(select * from Ticket con); DataSet ds = new DataSet(); SqlDataAdapter da = new SqlDataAdapter(comm); da.Fill(ds vtable); con.Close(); dataGridView1.DataSource = ds.Tables[0]; } private void btnSell_Click(object sender EventArgs e) { SqlConnection con = new SqlConnection(@Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\Database1.mdf;Integrated Security=True;User Instance=True); con.Open(); SqlCommand comm = new SqlCommand(select max(TransactionID) from Ticket con); int lastID = Convert.ToInt32(comm.ExecuteScalar()); comm = new SqlCommand(update Ticket set Qnt=Qnt+ + textBox1.Text.Trim() +  where TransactionId= + lastID con); comm.ExecuteNonQuery(); ShowData(); } Download Project File

Niradhip Chakraborty · Answer

If I understood your problem properley then after selling each ticket you are entering the records in database. Sat your table name is Ticketdetails. You can name the first field as TD_seq_Id which is primary key and set the autoincrement property. so no need to worry about this field. No need to insert value for this field when you are inserting a record in the table. As soon as you insert a record to this table the value is automatically increase by one for this field. So from this column you can able to know how many tickets u sold. Select the daytatype as integer for this field. Example: If you insert first record this field will show 1 if you insert 5 records this field will show 5. Set the autoincrement property for this field like this. Select the column in database go to column properties select identity specification set it Yes and make sure identity Increment is 1 and identity seed is also set to 1. Now fetching this field value you can easily Know how many tickets you sold. Create a session value where you always store the maximum quantity of tickets or crate a field in database to store the maximum Value. Now whenever you want to show the remaining quantity subtract this field value from TD_seq_Id field(which you have created as autoincrement field). If you have any doubts on this please let me know.