防止将空白记录写入数据库的是 SQL3 和 Python

Question

This is the first time I am posting so hope I do this correctly.

Can anyone assist me with a problem that I do not seem to be able to get past. I have had a good google but not found an answer. I am using Python 3.7 and SQL3

I am trying to prevent a record being written to the database if the 'f_name' field is blank.

I have tried to put a condition on the conn.commit() from not writing - did not work I have tried to do a condition and indent the c.execute if f-name is blank but that has not worked as I guess it has not got the input yet.

if I print out f_name after the c.execute I get "..entry2" regardless if there is an input or not if that makes any difference or gives a clue. I am guessing it is being written directly to the database and does not exist as a variable.

The error check I use is as follows (I have used it successfully elsewhere so it should be ok)

if f_name =="":
          print("No valid Data in First name field")
          return
else:
          conn.commit()

and I tried using the error check on the conn.commit() but I am guessing it is auto commiting.

Can anyone please give me an idea of how to prevent a blank f_name being accepted in this scenario?

Here is the code being called -

def submit():
    # Connect to database
    conn = sqlite3.connect('address_book.db')
    c = conn.cursor()

    six_month_reminder = ("f")
    annual_reminder = ("f")
    six_month_reminder_sent = ("f")
    annual_reminder_sent = ("f")

    # Insert Into Table
    c.execute("INSERT INTO addresses VALUES (:f_name, :l_name, :address, :city, :state, :zipcode, :six_month_reminder, :annual_reminder, :six_month_reminder_sent, :annual_reminder_sent)",
            {
                'f_name': f_name.get(),
                'l_name': l_name.get(),
                'address': address.get(),
                'city': city.get(),
                'state': state.get(),
                'zipcode': zipcode.get(),
                'six_month_reminder': six_month_reminder,
                'annual_reminder': annual_reminder,
                'six_month_reminder_sent': six_month_reminder_sent,
                'annual_reminder_sent':annual_reminder_sent
            })

    conn.commit()
    conn.close()

Answer 1

thanks for contributing ot SO.

In your code chunk it is missing the part in which you declare f_name , l_name , address ...

Assuming you have declared those in a chunk you didn't write in the question, I assume here that fname is set and it is a dictionary; the most straigthforward way is to check when performing the get() :

    ...
    annual_reminder_sent = ("f")

    if f_name.get() == '' or f_name.get() is None:
        return
    ...

EDIT: the second statement for the or is needed as in case of key is not in the dictionary get will return None , see Python documentation about .

In the case you missed that, the use of get() is supposed for dictionaries. For example if you try this in Python REPL:

>> d = {
   "key1": 1,
   "key2": 2
}
>> print(d.get("key1"))

will return 1 . Dictionaries are key-value maps.

In your case it seems you are doing something wrong as you are using get() on names that are not dictionaries.