ดูทีครับโค้ดนี้ผิดยังไง

Dim sqlquery = "SELECT * FROM member WHERE Username = ' " + textuser.Text + "'"
Dim myCommand As New MySqlCommand
myCommand.Connection = conn
myCommand.CommandText = sqlquery


myAdpter.SelectCommand = myCommand
Dim myData As MySqlDataReader
myData = myCommand.ExecuteReader()

If myData.HasRows Then
MsgBox("User exists!!")
Else
conn.Open()
Dim registerfinal As New MySqlDataAdapter

sqlquery = "INSERT INTO member (Username,Password) VALUES ('" + textuser.Text + "','" + textpass.Text + "')"
myCommand.Connection = conn
myCommand.CommandText = sqlquery

registerfinal.SelectCommand = myCommand
myData = myCommand.ExecuteReader

MsgBox("สมัครสมาชิกเรียบร้อย")
textuser.Clear()
textpass.Clear()
Me.Hide()
End IF


มัน Error Error "Duplicate entry 'boss' for key 'PRIMARY'" อะครับ