How can I make to make a complex query for my login system?-CodePudding

I want a login system which relates to a register database I made

I am trying to make a complex query which takes the user input:

    Entry(self.root,
          textvariable=self.username)  ##There is more but I want this to be as minimal as possible 
          
    Entry(self.root,
          textvariable=self.password,
          show="*")

This user input then gets compared with the one in the database. This is where I am finding it diffucult:

def login(self):
    con = sqlite3.connect("register.db")  ##The database which I want to open and compare user inputs to 
    c = con.cursor()
    c.execute("SELECT * FROM register")
    slist = c.fetchall()
    values = [row[0] for row in slist]
    values2 = [row[1] for row in slist]
    if self.username.get() == values and self.password.get()==values2:
        command=self.invcon  ##A external thing I want to open if the user enters the data in correctly
    else:
        messagebox.showerror("Error","Error"parent=self.root)
    con.commit()
    con.close()

The error which is now happening is instead of opening the new window it moves into the else and pops up with the error box. Database

CodePudding user response：

The SQL "SELECT username * FROM register" should be "SELECT * FROM register".

Also values and values2 are list, so the comparison between a string (self.username.get() or self.password.get()) and a list will always be False.

However, you don't need to select all records from the table, just select the record with the username and password is enough:

def login(self):
    con = sqlite3.connect("register.db")  ##The database which I want to open and compare user inputs to 
    c = con.cursor()
    # assume the fields required are 'username' and 'password'
    # change them to suit your table definition
    c.execute("SELECT 1 FROM register WHERE username = ? AND password = ?", (self.username.get(), self.password.get()))
    result = c.fetchone() # get the record if any
    if result:
        # record found
        command=self.invcon  ##A external thing I want to open if the user enters the data in correctly
    else:
        # record not found
        messagebox.showerror("Error", parent=self.root)
    con.close()

CodePudding user response：

I don't understand all of the errors but when selecting something from a table (in this case 'register') you can either select things by listing them up like:

c.execute("SELECT username, password ... FROM register")

or you simply select everything:

c.execute("SELECT * FROM register")

In this case you did both ("SELECT username * FROM ...") which is why there could be an error

I hope this helped a bit

I wish you good luck

Regards Javid