edit

app.py

@@ -15,7 +15,8 @@ class App(Tk):
     def __init__(self):
         Tk.__init__(self)
         self._frame = None
-        self.switch_frame(Past_Purchase_Page)
+        #self.switch_frame(Past_Purchase_Page)
+        self.switch_frame(customerItem_Page)
 
     def switch_frame(self, frame_class):
         new_frame = frame_class(self)

customerItem.py

@@ -8,20 +8,15 @@ class customerItem_Page(Frame):
     def __init__(self, master):
         Frame.__init__(self, master)
         self.master = master
-
-        def show():
-            conn = sqlite3.connect('products.db')
+        getProducts()
 
-            c = conn.cursor()
-
-            c.execute('''
-                SELECT * FROM products
-            ''', [''])
-
-            for product in c.fetchall():
-                print(product)
-
-            conn.commit()
-            conn.close()
-
-        filter_btn = Button(self, text="FILTER", command = show)
+    def getProducts():
+        my_conn = sqlite3.connect('products.db')
+        r_set=my_conn.execute('''SELECT * from products''');
+        i=0 # row value inside the loop 
+        for product in r_set: 
+            for j in range(len(product)):
+                e = Entry(self, width=10, fg='blue') 
+                e.grid(row=i, column=j) 
+                e.insert(END, product[j])
+            i=i+1

data.py

@@ -23,11 +23,11 @@
   INSERT INTO products VALUES (?,?,?,?,?,?)
   ''',
   [row['Category'],
-  row['Cost ($)'],
+  row['Cost'],
   row['Model'],
-  row['Price ($)'],
+  row['Price'],
   row['ProductID'],
-  row['Warranty (months)']]
+  row['Warranty']]
   )
 
 # cursor.execute('''

test.py

@@ -1,6 +1,6 @@
 import sqlite3
 
-connection = sqlite3.connect('items.db')
+connection = sqlite3.connect('products.db')
 cursor = connection.cursor()
-cursor.execute('SELECT * FROM products WHERE ItemID < 1005')
+cursor.execute('SELECT * FROM products')
 print(cursor.fetchall())