Using .get() to pull a barcode from a customtkinter.CTkEntry box

Question

This is part of a much larger project I'm working on, but I'm trying to break it down to the most basic question I could ask. How do I write the following line?

mycursor = mydb.cursor()
UPC_entry = customtkinter.CTkEntry(root, placeholder_text = "Barcode")

search = "SELECT Description FROM doitbest WHERE PrimaryUPC = '%s'" 
mycursor.execute(search, [UPC_entry.get()])
myresult = mycursor.fetchall()
for x in myresult:
        print(x)

select_button = customtkinter.CTkButton(root, text="Search", command=search)

I'm trying to use Python to search my MySQL database by using CustomTkinter as a GUI. Long story short, I want to scan a barcode into a CTkEntry box (UPC_entry), press the CTkButton that I made, have it pull the barcode from the CTkEntry box, and then use that barcode to search my database for the relevant information. No matter how I try to write the above line, I keep getting errors. It all comes down to the last part "UPC_entry.get()". I don't know how to get the barcode out of the CTkEntry box (UPC_entry) and use that to search the database. If I replace UPC_entry.get() with a regular barcode (eg. 077922843671), it will come up with the correct information. I just don't understand what I'm doing wrong. Is .get() even the right thing I should be using? I greatly appreciate any suggestions you guys might have.

Answer 1

command= needs Python function name without () but you put SQL query.

def my_function():
    #...code...

...CTkButton(..., command=my_function)  #  <- function's name without ()

When you press button then tkinter gets this function's name and it uses () to execute it. It can't use string as function's name.

---

You have to create function which runs SQL and assign this function to button.

# --- functions ---

def my_function():
    search = "SELECT Description FROM doitbest WHERE PrimaryUPC = '%s'" 
    mycursor.execute(search, [UPC_entry.get()])
    myresult = mycursor.fetchall()
    for x in myresult:
            print(x)

# --- main ---

mycursor = mydb.cursor()
UPC_entry = customtkinter.CTkEntry(root, placeholder_text = "Barcode")

select_button = customtkinter.CTkButton(root, text="Search", command=my_function)  #  <- function's name without ()

---

BTW: this function's name without () is called callback (not only in Python but also in other languages - ie. in JavaScript)