So I have a UTF8MB4 database on phpMyAdmin for MySQL, and I'm using PDO in PHP for interacting with my database, and I really want to know, just to be 100% sure that the 'bindValue' function really escapes data, I've heard that the SQL Query and the data is sent differently but I want to know if it's true, is there any way 'bindValue' can be bypassed where SQL injection can occur?  Example Code:  $db = new PDO(...);  //Notice how I'm not sanitizing $_GET, is this okay? $query = $db-&gt;prepare("SELECT * FROM table WHERE Username = :username"); $query-&gt;bindValue(":username", $_GET["username"]); $query-&gt;execute(); echo "Rows: " . $query-&gt;rowCount();  while($row = ...) {     echo $row["Username"]; }
If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening?
Getting "Authentication is required" when trying to access the Play Store Over the past week, whenever I try  to open the Play Store/Market app on my phone, the app thinks for a while and then displays this error message:     Authentication is required. You need to sign into your Google Account.   But I am indeed signed into my Google account, as seen in other Google applications running on the phone, and as seen if I open the menu in the Market app and click the "Accounts" button.  I suspect this might be related to the fact that over the past few months I've had two different Google accounts synced to this device, and I have recently removed one of them from the phone. No other Google application has had any problems with removing one account.  Does anyone know how I can solve this issue? I can still install applications by using the market website (now "Google Play"), but this is still a big inconvenience. I also think I stopped getting updates. So from what I remember it was on cable TV. The main hero was a TV actor zapped to a alien planet. It had a evil overlord with a virgin priestesses. She wants to get laid but he refuses because the next priestesses is only three. Regardless it's a parody things include a man who was maimed by the evil overlord wants revenge the hero eventually screws the virgin priestesses it cuts to scenes of a train going into a tunnel and a volcano erupting. Any way to sync directory structure when the files are already on both sides? I have two drives with the same files, but the directory structure is totally different.  Is there any way to 'move' all the files on the destination side so that they match the structure of the source side? With a script perhaps?    For example, drive A has:    /foo/bar/123.txt /foo/bar/234.txt /foo/bar/dir/567.txt   Whereas drive B has:  /some/other/path/123.txt /bar/doo2/wow/234.txt /bar/doo/567.txt   The files in question are huge (800GB), so I don't want to re-copy them; I just want to sync the structure by creating the necessary directories and moving the files.  I was thinking of a recursive script that would find each source file on the destination, then move it to a matching directory, creating it if necessary. But -- that's beyond my abilities!  Another elegant solution was given here: The characteristic and minimal polynomial of a companion matrix of a monic polynomial $f \in \mathbb F\left[x\right]$ in $1$ variable $x$ over a field $\mathbb F$ plays an important role in understanding the structure of finite dimensional $\mathbb F[x]$-modules.  It is an important fact that the characteristic polynomial and the minimal polynomial of $C(f)$ are both equal to $f$. This can be seen quite easily by induction on the degree of $f$.  Does anyone know a different proof of this fact? I would love to see a graph theoretic proof or a non inductive algebraic proof, but I would be happy with anything that makes it seem like more than a coincidence! I am a physics Master's student.  I have good grades, with CGPA above 9(/10)(However, all courses in my university are graded on a curve so the actual marks are significantly lower than 90%). This has been my marks throughout my undergraduate and graduate courses and I was happy because this was above average. Also, my summer projects in UG were usually computational and any difficulty I had in theoretical aspects I attributed it to my inexperience in advanced Physics.   However, recently I have started to work on pure theoretical project and while reading for the project I realized that I consistently miss some details from each topic. I understand the general idea, can re-derive most of the equations(with some effort) however when I discuss things with my professor or when I read further topics I realize that I have missed certain key-details. This is exactly similar to the case of me missing a few key questions in my exams and getting that 9 grade point instead of 10(or at-least I think so). I was not worried about this before but now I realize that there is some flaw in the way I study (but I do not know what).   Since I want to apply for Physics PhD I realized that I will need to have solid concepts and it would be best to correct my mistakes but I do not know how or even what could be the reason for my imperfect understanding.  Any direct suggestion would help or even certain general guidelines on what I can do.    Things I've tried recently -   1) I've started to written down almost everything I read. This is slightly laborious but is certainly helping. It also helps me to gloss over the things I read previously when I come back the next day.  2) I completely avoid smartphone when I'm library/study room so that I won't get distracted. Not sure if it helps me solve the above problem but certainly helps me study better in general.  3) I've tried to read the topics from several sources. The books I am reading is somewhat like a collection of research papers and hence does not have a exercises. So I though reading from various sources might help get better ideas but it's not really helping because most other sources are too high level as an introductory text. But this will probably help me in cases where it's practical to do this.  4) Somewhat similar to point (1)- I am trying reread, whenever I can, what I've done until that point. But not sure how much this will help me in filling the gaps. Today is the release of Ubuntu 21.04 (Hirsute Hippo). And I can't update to this version. And also I selected ‘Notify me of a new Ubuntu version’ and changed it to ‘For any new version' on the Updates tab on Software &amp; Update, but it's still not working. In addition, in the terminal, I've written: sudo do-release-upgrade -c  And output was: Checking for a new Ubuntu release No new release found.  What should I do? Assigning integer to finite CW complex such that following hold. How to find image coordinates of the rendered vertex? I have a simple mesh of a cube.  I would like to know what are the coordinates of each vertex in the rendered image (i.e. for each 3d vertex I'd like to know it's pixel coordinates).  Is there a way to do this?  Clarification:  I'm experimenting with a pose estimation algorithm (i.e. finding out the 3d pose of the object) from a (set of) 2d image(s).  Instead of taking an image of a real object with a real camera I synthetically render the image of a cube using blender.  In this way I know the pose of the object and the intrinsics of the camera, so I can easily validate the results of the pose estimation algorithm. Pose estimation algorithms usually require to provide them with world points on the object and the corresponding image points.  So what I'm looking for is a way to produce a dump of correspondences of the 3d point &lt;--> image point as a byproduct of the rendering procedure. Thanks, Alex Are the foods in the Star Wars Universe the same as ours'? Do they have strawberries or potatoes or something? I know that they might have some food other than the food that we also have, but I'm wondering if they have any food like ours'. Evaluate: $\lim_{n\to\infty}\left({2\sqrt n}-\sum_{k=1}^n\frac1{\sqrt k}\right)$ Why are second order linear PDEs classified as either elliptic, hyperbolic or parabolic? Is there a geometric interpretation of second order linear partial differential equations which explains why they are classified as either elliptic, hyperbolic or parabolic, or is this just a naming convention? That is, do they have any relation with actual ellipses, hyperbolas and parabolas? How do I get the number of days between two dates in JavaScript? If RSA is limited to 117-200 bytes or so, is that a very limited use case? Am I missing something, or is RSA very very limiting when it comes to ecrypting data when it comes to the actual message size?  I have read that you can only encrypt a message of around 117 to 200 bytes in size (depending on your key size: 1024 or 2048 bits). Is this correct?  If so, I think I have read people suggesting on using it for larger files. I guess they are just repeating the process many times over and over in blocks of 117 bytes? Capture characters from standard input without waiting for enter to be pressed I would like to open 4 Notepad++ windows at once, in the same pannel. Currently, I am only able to split it into two, and would like to know if there is a plugin that enables 4 views at at same time, or 3.   thanks How do I read the manifest file for a webapp running in apache tomcat? Why does Math.Floor(Double) return a value of type Double? SF Short Story: alien apes invade during nuclear war Does $\sum\limits_{k=1}^n 1 / k ^ 2$ converge when $n\rightarrow\infty$? I can prove this sum has a constant upper bound like this: $$\sum_{k=1}^n \frac1{k ^ 2} \lt 1 + \sum_{k=2}^n \frac 1  {k (k - 1)} = 2 - \frac 1 n \lt 2$$ And computer calculation shows that sum seems to converge to 1.6449.  But I still want to know:  Does this sum converge? Is there a name of this sum (or the series $\frac{1}{k^2} $)? How to see download count of an Android app on Google Play store? I cannot see the download counts of one app on Google Play.   How can we know that number of one app?