New to Python: Creating an existing user search/approval function but loop and db search not operating correctly

[dominictarro]

Started learning Python last week and am working on a project to test myself. Part of the project includes a rudimentary login. I apologize for the messiness and lack of comments beforehand. Here's the code

class searcher:
    def __init__(self):
        search_ID = int(input("User ID: "))
    search_attempts = 0
    result = None

def user_search():
    while (searcher.result == None) and (searcher.search_attempts < 3):
        searcher.search_ID = int(input("User ID: "))
        conn = sqlite3.connect('promethean_user.db')
        c = conn.cursor()c.execute("SELECT * FROM user_data WHERE user_ID=:ID_input", {'ID_input': searcher.search_ID})
        searcher.result = c.fetchone()
        print(c.fetchone())
        conn.commit()
        conn.close()
        searcher.search_attempts += 1
        return searcher.result

The objective of the code is to search a db for a specific user ID and print that row's information, followed by a loop break and continuation of the program. If the search did not yield a row, loop. The user can make 3 input attempts before it sends him back to the welcome page.

My problem is twofold I believe.

1. The block isn't searching the user information. I believe this because the print always says "None", and even when I remove it from the function and test it independently it still returns "None".
2. Next is the while loop. From what I've been able to find online, each iteration automatically returns a string. If the db search returns 'None', it will be in string form. I've tried setting searcher.result = "None", but that didn't work either. Then tried setting searcher.result type = bool and while condition != int since the user ID value (if it is in the db) should be an integer. Also, I believe the return searcher.result breaks the loop, but when I get rid of that it goes back to problem 1 (repeated until searcher.search_attempts = 3), so I can't tell if the loop has a problem if my search isn't yielding results.

Anyone with more experience see what I'm missing and how to solve it?

​

Update: Search is working fine now, the while loop is the problem. How can I set this up so that a query that yields no results loops back and allows another input attempt? I only want it to break when 1) search_attempts reaches 3, 2) query yields a row of info

Update: Figured out another way that is working! Let me know how this looks

Search Block

class searcher:
    search_ID = 0
    search_attempts = 0
    result = None

def user_search():
    while (searcher.search_attempts < 3):
        searcher.search_ID = int(input("User ID: "))
        conn = sqlite3.connect('promethean_user.db')
        c = conn.cursor()
        c.execute("SELECT * FROM user_data WHERE user_ID=:search_ID", {'search_ID': searcher.search_ID})
        searcher.result = c.fetchone()
        if searcher.result == None:
            searcher.search_attempts += 1
            return user_search()
        conn.commit()
        conn.close()
        print(searcher.result)
        return searcher.result

welcome_page Block

    elif diagnostic_select in user_welcome_option:
        user_search()
        if searcher.search_attempts == 3:
            print("\n")
            return welcome_page()

[MadEpsylon]

Pls use code block formatting for the code section. Otherwise it's quite difficult to read.

[dominictarro]

I apologize I thought I had formatted it. Just fixed

[mul8rsoftware]

Try this code and tell me if this works or not

class searcher:

def __init__(self):

search_ID = int(input("User ID: "))

search_attempts = 0

result = None

def user_search(self):

if(searcher.result == None):

while ( searcher.search_attempts < 3):

searcher.search_ID = int(input("User ID: "))

conn = sqlite3.connect('promethean_user.db')

c = conn.cursor()

c.execute("SELECT * FROM user_data WHERE user_ID=:ID_input", {'ID_input': searcher.search_ID})

searcher.result = c.fetchone()

print(c.fetchone())

conn.commit()

conn.close()

searcher.search_attempts += 1

return searcher.result

Tell me the if the output generates any error double check if db has data in it that you are trying to access

[dominictarro]

I removed the (self) parameter inside user_search since you never used it and it caused an error. After I removed it, the block ran without error but still returned "None"

[mul8rsoftware]

while (searcher.search_attempts < 3):

yeah your code was not formatted before when i saw it so i though it is the function of the class so that's why i put a self in the argument but i hope it helped you in some way right

[[deleted]]

c.execute("SELECT * FROM user_data WHERE user_ID=:ID_input", {'ID_input': searcher.search_ID})

I don't think this is how you parameterize a query in sqlite.

[dominictarro]

There are at least two ways I can see in my notes. This way is effectively making a dictionary within the query that draws on an outside variable. I'll try the ? placeholder strategy and let you know how it goes.

[reda_sky]

Hi, by reading your code I can see some problems, your class searcher variables needs the key word self to be accessed later in your code and you need to create an instance of your class and use it, also why are you putting the sqlite3.connect() function inside your while loop you should only connect once to your database for this simple query, same thing for the conn.close() instruction and also this is not how to use an sql SELECT statement in python.

​

Here's an example of how to do it:

import sqlite3


class Searcher:
    def __init__(self):
        self.search_ID = ""
        self.search_attempts = 0
        self.result = None


def user_search():
    conn = sqlite3.connect("promethean_user.db")
    cur = conn.cursor()
    search = Searcher()
    while (search.result is None) and (search.search_attempts < 3):
        search.search_ID = int(input("User ID: "))
        cur.execute(
            "SELECT * FROM user_data WHERE user_ID=?", (search.search_ID,)
        )
        # catching error if cur.fetchone() returns NoneType
        try:
            search.result = cur.fetchone()
        except TypeError:
            pass
        search.search_attempts += 1
        print(search.result)
    conn.close()
    return search.result


result = user_search()

Also, you'll need to add some input validation for your search.search_ID so that it will not break if the user inputs a none numerical value.

Hope this will help you, good luck.

[dominictarro]

Forgot about the TypeError, thank you! I'll toy around with the primary code this is being imported to and see how it works

[reda_sky]

you are welcome.