How to do this with treeview and sqlite3?

Hey Guys, I wanted to create a treeview in tkinter using data present in my sqlite3 database.

def show():
        conn = sqlite3.connect("userdata.db")
        c = conn.cursor()
        c.row_factory = sqlite3.Row
        c.execute("SELECT * from c20;")
        data = c.fetchone()
        precise_data = c.fetchall()
        names = data.keys()
        my_tree = ttk.Treeview(table_frm)
        my_tree["columns"] = tuple(names)

        my_tree.column("#0", width=0, minwidth=25)
        for i in names:
            my_tree.column(i, width=50, minwidth=25)

        # Creating headings
        my_tree.heading("#0", text="Test", anchor=W)
        for j in names:
            my_tree.heading(j, text=j, anchor=W)

        #my_tree.insert(parent="", index='end', iid=0, text="Parent", values=("0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0"))

        for x in precise_data:
            for y in x:
                my_tree.insert(parent="", index="end", iid=0, text="", values=())


So this being the function show, where function fetches out the data from the database.

Now, while getting the data into the treeview table, I need to add values in it using the .insert function. I am able to get the data in the form of the variable y, but how can I place the values of the list of data contained in the variable y?

Sample List(for y) = ["10", "12",...]

One more thing to mention, how can I get this thing done, if the length of the list being n, or any huge or small number?

Thanks in advance.