How to stop loop - vb.net

Question

I have a problem with Do until loop. When the record successfully saved and message-box appeared, after clicking the OK button it just shows the message-box and repeat it endlessly. I don't know what's the code for that. Please help.
MySqlConn.Open()
Dim last, midd, first, age, occu, phone As MySqlDataReader
Dim cmd1, cmd2, cmd3, cmd4, cmd5, cmd6, cmd7, cmd8, cmd9, cmd10, cmd11 As New MySqlCommand
Dim query1, query2, query3, query4, query5, query6, query7, query8, query9, query10, query11 As String
'lastname query
query1 = "SELECT * FROM newpatient WHERE Lastname ='" & txtLastname.Text & "'"
cmd1 = New MySqlCommand(query1, MySqlConn)
last = cmd1.ExecuteReader
'first query
query2 = "SELECT * FROM newpatient WHERE Firstname ='" & txtFirstname.Text & "'"
cmd2 = New MySqlCommand(query2, MySqlConn)
last.Close()
first = cmd2.ExecuteReader
'middle query
query3 = "SELECT * FROM newpatient WHERE Middlename ='" & txtMiddlename.Text & "'"
cmd3 = New MySqlCommand(query3, MySqlConn)
first.Close()
midd = cmd3.ExecuteReader
'age query
query4 = "SELECT * FROM newpatient WHERE Age ='" & txtAge.Text & "'"
cmd4 = New MySqlCommand(query4, MySqlConn)
midd.Close()
age = cmd4.ExecuteReader
'gender query
query5 = "SELECT * FROM newpatient WHERE Occupation ='" & txtOccupation.Text & "'"
cmd5 = New MySqlCommand(query5, MySqlConn)
age.Close()
occu = cmd5.ExecuteReader
'phone query
query6 = "SELECT * FROM newpatient WHERE Mobile_Number ='" & txtMobileNumber.Text & "'"
cmd6 = New MySqlCommand(query6, MySqlConn)
occu.Close()
phone = cmd6.ExecuteReader
Do While last.HasRows = 0 And first.HasRows = 0 And midd.HasRows = 0 And occu.HasRows = 0 And phone.HasRows = 0 And age.HasRows = 0
Dim cmd As MySqlCommand = MySqlConn.CreateCommand
cmd.CommandText = String.Format("INSERT INTO newpatient (ID, Lastname, Firstname, Middlename, Age, Mobile_Number, Gender, Address, Occupation, Month, Day, Year )" &
"VALUES ('{0}' ,'{1}' ,'{2}' ,'{3}' ,'{4}' ,'{5}' , '{6}', '{7}', '{8}', '{9}', '{10}', '{11}' )",
txtID.Text,
txtLastname.Text,
txtFirstname.Text,
txtMiddlename.Text,
txtAge.Text,
txtMobileNumber.Text,
cmbGender.SelectedItem,
txtAddress.Text,
txtOccupation.Text,
cmbMonth.SelectedItem,
cmbDay.SelectedItem,
cmbYear.SelectedItem)
phone.Close()
Dim affectedrows As Integer = cmd.ExecuteNonQuery()
If affectedrows > 0 Then
MsgBox("Record successfully saved!", MsgBoxStyle.Information, "Success")
'AUTO GENERATE RANDOM IDs
Dim random As New Random
Dim id As Integer
id = (random.Next(100000000, 1000000000))
txtID.Text = id
'CLEARS TEXTBOXES
txtMobileNumber.Text = ""
txtLastname.Text = ""
txtFirstname.Text = ""
txtMiddlename.Text = ""
txtAge.Text = 0
cmbGender.SelectedItem = ""
cmbDay.SelectedItem = ""
cmbMonth.SelectedItem = ""
cmbYear.SelectedItem = 0
txtAddress.Text = ""
txtOccupation.Text = ""
txtLastname.Select()
Else
MsgBox("Saving record failed.", MsgBoxStyle.Critical, "Failed")
'AUTO GENERATE RANDOM IDs
Dim random As New Random
Dim id As Integer
id = (random.Next(100000000, 1000000000))
txtID.Text = id
'CLEARS TEXTBOXES
txtMobileNumber.Text = ""
txtLastname.Text = ""
txtFirstname.Text = ""
txtMiddlename.Text = ""
txtAge.Text = 0
cmbGender.SelectedItem = ""
cmbDay.SelectedItem = ""
cmbMonth.SelectedItem = ""
cmbYear.SelectedItem = 0
txtAddress.Text = ""
txtOccupation.Text = ""
txtLastname.Select()
End If
Loop
'CLEARS TEXTBOXES
txtMobileNumber.Text = ""
txtLastname.Text = ""
txtFirstname.Text = ""
txtMiddlename.Text = ""
txtAge.Text = 0
cmbGender.SelectedItem = ""
cmbDay.SelectedItem = ""
cmbMonth.SelectedItem = ""
cmbYear.SelectedItem = 0
txtAddress.Text = ""
txtOccupation.Text = ""
MsgBox("Patient has already registered!", MsgBoxStyle.Critical, "Already registered")
MySqlConn.close()

Answer 1

To stop the loop requires a call to Exit, like so:
Exit Do
Having said that, you should never just call Exit without requiring a condition to be met, or you can encounter unexpected behavior.
But you've got much larger problems here. I'm going to list them out quickly and include a quick pseudocode suggestion (as in I've never used MySql in .Net, so not at all familiar with the API, so this code WILL need modified before it would work)
Dim cmd As MySqlCommand = MySqlConn.CreateCommand
cmd.CommandText = "INSERT INTO newpatient (ID, Lastname, Firstname, Middlename, Age, Mobile_Number, Gender, Address, Occupation, Month, Day, Year )" &
"VALUES (:ID, :Lastname, :Firstname, :Middlename, :Age, :Mobile_Number, :Gender, :Address, :Occupation, :Month, :Day, :Year)"
cmd.Parameters.Add(new MySqlParameter(":ID", txtID.Text))
cmd.Parameters.Add(new MySqlParameter(":Lastname", txtLastname.Text))
cmd.Parameters.Add(new MySqlParameter(":Firstname", txtFirstname.Text))
cmd.Parameters.Add(new MySqlParameter(":Middlename", txtMiddlename.Text))
cmd.Parameters.Add(new MySqlParameter(":Age", txtAge.Text))
cmd.Parameters.Add(new MySqlParameter(":Mobile_Number", txtMobileNumber.Text))
cmd.Parameters.Add(new MySqlParameter(":Gender", cmbGender.SelectedItem))
cmd.Parameters.Add(new MySqlParameter(":Address", txtAddress.Text))
cmd.Parameters.Add(new MySqlParameter(":Occupation", txtOccupation.Text))
cmd.Parameters.Add(new MySqlParameter(":Month", cmbMonth.SelectedItem))
cmd.Parameters.Add(new MySqlParameter(":Day", cmbDay.SelectedItem))
cmd.Parameters.Add(new MySqlParameter(":Year", cmbYear.SelectedItem))
Dim affectedrows As Integer = cmd.ExecuteNonQuery()
If affectedrows = 1 Then
MsgBox("Record successfully saved!", MsgBoxStyle.Information, "Success")
Else
If affectedrows = 0 Then
'Most likely the record already existed, call an update here and if you get 1 result, the record existed and you just saved changes
MsgBox("Patient has already registered!", MsgBoxStyle.Critical, "Already registered")
'You could change the above to a Yes/No question about updating the record and have the result in an if to update the record at the user's discretion.
cmd = MySqlConn.CreateCommand
cmd.CommandText = "UPDATE newpatient " &
"SET Lastname = :Lastname, Firstname = :Firstname, Middlename = :Middlename, Age = :Age, Mobile_Number = :Mobile_Number, " &
" Gender = :Gender, Address = :Address, Occupation = :Occupation, Month = :Month, Day = :Day, Year = :Year " &
"WHERE ID = :ID"
cmd.Parameters.Add(new MySqlParameter(":ID", txtID.Text))
cmd.Parameters.Add(new MySqlParameter(":Lastname", txtLastname.Text))
cmd.Parameters.Add(new MySqlParameter(":Firstname", txtFirstname.Text))
cmd.Parameters.Add(new MySqlParameter(":Middlename", txtMiddlename.Text))
cmd.Parameters.Add(new MySqlParameter(":Age", txtAge.Text))
cmd.Parameters.Add(new MySqlParameter(":Mobile_Number", txtMobileNumber.Text))
cmd.Parameters.Add(new MySqlParameter(":Gender", cmbGender.SelectedItem))
cmd.Parameters.Add(new MySqlParameter(":Address", txtAddress.Text))
cmd.Parameters.Add(new MySqlParameter(":Occupation", txtOccupation.Text))
cmd.Parameters.Add(new MySqlParameter(":Month", cmbMonth.SelectedItem))
cmd.Parameters.Add(new MySqlParameter(":Day", cmbDay.SelectedItem))
cmd.Parameters.Add(new MySqlParameter(":Year", cmbYear.SelectedItem))
affectedrows = cmd.ExecuteNonQuery()
If affectedrows = 1 Then
MsgBox("Record successfully saved!", MsgBoxStyle.Information, "Success")
Else
MsgBox("Saving record failed.", MsgBoxStyle.Critical, "Failed")
End If
Else
'Should never get here. We covered 0 and 1 in the other two logic branches.
'In this small demo, handling when more than 1 record gets updated is out of scope.
End If
End If
'CLEARS TEXTBOXES
txtMobileNumber.Text = ""
txtLastname.Text = ""
txtFirstname.Text = ""
txtMiddlename.Text = ""
txtAge.Text = 0
cmbGender.SelectedItem = ""
cmbDay.SelectedItem = ""
cmbMonth.SelectedItem = ""
cmbYear.SelectedItem = 0
txtAddress.Text = ""
txtOccupation.Text = ""
txtLastname.Select()
MySqlConn.close()
Never build queries from strings where you rely on a user for some of those strings. This leaves you vulnerable to SQL injection attacks (try putting a name with an apostrophe in it in one of the name fields and watch the flurry of errors. Then realize someone with malicious intentions could do serious damage to your database if you don't sanitize your inputs) Always parameterize your queries wherever possible!!
Don't repeat yourself! (AKA the DRY principle) If you find yourself copying/pasting the same block of code from place to place, that means you're doing something wrong. In this case, it was that you got stuck on the idea that you HAD to have a loop, and to make sure you're input fields were cleared, you just copied the code to clear them to 3 different places in the codepath. If you find that you NEED to run the same code repeatedly throughout your programs codepath, then generalize it and put it in a function. Your eyes and the eyes of the next person to read/maintain your code will appreciate it!
You need some more knowledge/experience with SQL, and that's ok, everyone had to start somewhere. In the sample, I removed ALL of your select queries in favor of trying ONE insert query and branching the logic based on the result of that 1 query. Much easier to read/maintain. Also, Identity values should be handle BY your sql instance, not in code. You generally want them used sequentially to avoid collisions and you don't want them modified by/visible to end users. Correcting the properties of the ID column allows removal of the random generation code. Just remember that when you insert into a table with an identity column that you don't need to include the identity column in your INSERT statement (SQL will fill that column for you)