You are inserting a list or tuple into the listbox instead of a string. You need to explicitly convert each row to a string before passing to the insert method. Otherwise, the underlying tcl interpreter will try to preserve the list-like structure of the data by adding curly braces or backslashes when converting the value to a string.
Consider this code:
query = ('''SELECT * FROM Employee;''' )
cur.execute(query)
row = cur.fetchall()
row a list of lists. For each item in row, you have a list of values for each column in that row.
Later, you add each row to the listbox like this:
for x in row:
listbox.insert(END,x)
As stated earlier, x is a list of data for each column. However, listbox.insert takes a string. Since it is not a string, tkinter will convert it to a string using its own logic which may result in curly braces being added.
To avoid this, you should explicitly convert the list to a string before calling insert. The simplest way to do that is to add a space between each element:
listbox.insert(END, " ".join(x))
If “x” contains something other than strings, you’ll need to convert them to strings first. The final version might look something like this:
string_data = [str(data) for data in x]
listbox.insert(END, " ".join(string_data))