Start by finding out why it crashed: use a
try ... catch
block around the body of your
database
and
cheackAccountStatus
methods, and log or display the error details in the
catch
block.
Use the debugger to examine the Exception object to see if there is Inner Exception information as well.
The error detail is important: it tells you why the app failed to do something - and until you have that, there is nothing sensible anyone can do.
When you have the error info, think about what it says, and try to work out why. My guess - and that's all it can possibly be - is that the error info will be complaining that the file doesn't exist - and that means you need to create it!
But don't do your code like that!
1) Never concatenate strings to build a SQL command. It leaves you wide open to accidental or deliberate SQL Injection attack which can destroy your entire database. Always use Parameterized queries instead.
When you concatenate strings, you cause problems because SQL receives commands like:
SELECT * FROM MyTable WHERE StreetAddress = 'Baker's Wood'
The quote the user added terminates the string as far as SQL is concerned and you get problems. But it could be worse. If I come along and type this instead: "x';DROP TABLE MyTable;--" Then SQL receives a very different command:
SELECT * FROM MyTable WHERE StreetAddress = 'x';DROP TABLE MyTable;
Which SQL sees as three separate commands:
SELECT * FROM MyTable WHERE StreetAddress = 'x';
A perfectly valid SELECT
DROP TABLE MyTable;
A perfectly valid "delete the table" command
And everything else is a comment.
So it does: selects any matching rows, deletes the table from the DB, and ignores anything else.
So ALWAYS use parameterized queries! Or be prepared to restore your DB from backup frequently. You do take backups regularly, don't you?
2) Never store passwords in clear text - it is a major security risk. There is some information on how to do it here:
Password Storage: How to do it.[
^]
And remember: if you have any European Union users then GDPR applies and that means you need to handle passwords as sensitive data and store them in a safe and secure manner. Text is neither of those and the fines can be .... um ... outstanding. In December 2018 a German company received a relatively low fine of €20,000 for just that.