I am attempting to remove an object from my sql database. I have been using this same method in multiple places and they all work fine except for here.
My Code:
foreach (TestCase testCase in testCaseList)
{
db.TestCases.Remove(testCase);
await db.SaveChangesAsync();
}
The error that I get from this code is: "The object cannot be deleted because it was not found in the ObjectStateManager"
I found a solution to this problem which was adding an attach. The resulting code was:
foreach (TestCase testCase in testCaseList)
{
db.TestCases.Attach(testCase);
db.TestCases.Remove(testCase);
await db.SaveChangesAsync();
{
With this code, I get the following error: "Store update, insert, or delete statement affected an unexpected number of rows(0)." I found some information on this error, but nothing that seemed to apply to my issue. Is there a specific reason these issues are arising and what can I do to solve the errors?
My issue resulted from the fact that I was actually removing the entity twice. For anybody that gets similar errors in the future, be sure to double check your code for duplicate statements.
Related
I need to fix some code that I didn't write and without documentation. The LINQ statement that follows sometimes throws the exception “item with the same key has already been added” but I haven't found a way to figure out where it throws the duplicate.
Return Me.Values.SelectMany(
Function(obj) obj.Users.Values.Distinct()).
Where(Function(u) u.UserIsInbox = False).
Distinct().
ToDictionary(Function(u) u.Code, Function(u) u)
I also tried to have all the contents of the collections printed but I had no results.
How can I do?
This code section i am getting error any ideas ?
public IEnumerable<LOBinfo> getLobinfo()
{
// var obj = from n in lobj.LOBinfoes select n;
return lobj.LOBinfoes.Select(m=>m).ToList();
// return obj.ToList();
}
I am not even using USING keyword ?
This issue been for a while and i referred many articles in stackoverflow itself but things looking bad for me .
Thank you for your suggestions
Underlying provider failed to open means, that at some point a database could not be reached, due to wrong connection settings for example or a previous failure etc...
The code you show here is allright, except for the fact you write a useless .Select you can drop the .Select(m=>m) and just leave the .ToList there.
Further, to find out what is causing your crash post the exact error message as well as the inner exception. (and the inner exception's inner exception and so on...)
Next to that the part "lobj.LOBinfoes" is probably a repository or something? You might as well post the code of that and the code of your data access object as well.
The error:
casper.test property is only available using the `casperjs test` command
Searched my entire codebase for "casper.test", "this.test", "#test", etc, and none are present. Looking at the casper code, one of these needs to be triggered for this error to be raised.
The error is intermittent and only occurs on some casper runs. Has anyone else gotten this bug? I'm running 1.1.0-beta3.
You can add
phantom.casperTest = true;
at the top of the test file.
Have you launch your script like this ?
casperjs test yourScript.js
It has nothing to do with launching it. Not sure why, but I also received this error on my code before writing to file. It went away after removing...
JSON.stringify(obj);
Again, I dont know what caused the issue. And it may be something else causing it for you. But if you find which piece of code is causing it, I have a solution.
My solution:
Use a handler for errors with a basic variable switch and turn off the error log for that portion of the step.
casper.on("error", function(err) {
if(custLog) {console.log(err);} //log the error
});
and in the step...
casper.then(function() {
custLog = false;
fs.write(fileName, JSON.stringify(content), 'w');
custLog = true;
});
You may or may not need to order the reorder the inner stack there.
In regards to Error handling in PHP -- As far I know there are 3 styles:
die()or exit() style:
$con = mysql_connect("localhost","root","password");
if (!$con) {
die('Could not connect: ' . mysql_error());
}
throw Exception style:
if (!function_exists('curl_init')) {
throw new Exception('need the CURL PHP extension.
Recomplie PHP with curl');
}
trigger_error() style:
if(!is_array($config) && isset($config)) {
trigger_error('Error: config is not an array or is not set', E_USER_ERROR);
}
Now, in the PHP manual all three methods are used.
What I want to know is which style should I prefer & why?
Are these 3 drop in replacements of each other & therefore can be used interchangeably?
Slightly OT: Is it just me or everyone thinks PHP error handling options are just too many to the extent it confuses php developers?
The first one should never be used in production code, since it's transporting information irrelevant to end-users (a user can't do anything about "Cannot connect to database").
You throw Exceptions if you know that at a certain critical code point, your application can fail and you want your code to recover across multiple call-levels.
trigger_error() lets you fine-grain error reporting (by using different levels of error messages) and you can hide those errors from end-users (using set_error_handler()) but still have them be displayed to you during testing.
Also trigger_error() can produce non-fatal messages important during development that can be suppressed in production code using a custom error handler. You can produce fatal errors, too (E_USER_ERROR) but those aren't recoverable. If you trigger one of those, program execution stops at that point. This is why, for fatal errors, Exceptions should be used. This way, you'll have more control over your program's flow:
// Example (pseudo-code for db queries):
$db->query('START TRANSACTION');
try {
while ($row = gather_data()) {
$db->query('INSERT INTO `table` (`foo`,`bar`) VALUES(?,?)', ...);
}
$db->query('COMMIT');
} catch(Exception $e) {
$db->query('ROLLBACK');
}
Here, if gather_data() just plain croaked (using E_USER_ERROR or die()) there's a chance, previous INSERT statements would have made it into your database, even if not desired and you'd have no control over what's to happen next.
I usually use the first way for simple debugging in development code. It is not recommended for production. The best way is to throw an exception, which you can catch in other parts of the program and do some error handling on.
The three styles are not drop-in replacements for each other. The first one is not an error at all, but just a way to stop the script and output some debugging info for you to manually parse. The second one is not an error per se, but will be converted into an error if you don't catch it. The last one is triggering a real error in the PHP engine which will be handled according to the configuration of your PHP environment (in some cases shown to the user, in other cases just logged to a file or not saved at all).
In a previous ticket i asked about logging PHP errors in MySQL which gives me:
function myErrorHandler($errno, $errstr, $errfile, $errline)
{
// mysql connect etc here...
$sql = "INSERT INTO `error_log` SET
`number` = ".mysql_real_escape_string($errno).",
`string` = ".mysql_real_escape_string($errstr).",
`file` = ".mysql_real_escape_string($errfile).",
`line` = ".mysql_real_escape_string($errline);
mysql_query($sql);
// Don't execute PHP internal error handler
return true;
}
// set to the user defined error handler
$new_error_handler = set_error_handler("myErrorHandler");
I can make this work but only if it is triggerred like this:
trigger_error("message here");
However, I also want the error handler to be called for all errors such as syntax errors like:
echo "foo;
But these errors are just outputted to the screen, what am i doing wrong?
You can only handle runtime errors with a custom error handler. The echo "foo error in your example happens when parsing (i.e. reading in) the source. Since PHP can not fully parse the code, it can also not run your error handler on this error.
If You're forced to test if syntax is correct, You can use php_check_syntax function, with filename parameter PHP Manual php_check_syntax
php_check_syntax also provides second parameter, witch when used will be populated by the error string, as far as i remember
That's indeed terrible way of error logging
You don't need not a single advantage of a database. Would you make a database lookup for the certain line number? Or order your results by file name?
database is a subject of many errors itself.
You've been told already that it's impossible to catch a parse error at the program logic level, because a syntactically wrong program will never run.
Let's take your code as an example. It will raise a MySQL error (because of poorly formed query) which you will never see. As well as any other errors occurred. That's what I am talking about.