Please note, this is purely for educational purposes only and I ALWAYS protect my SQL queries no matter what they are used for, it would be a majorly bad idea not to! This question specifically focuses on $_GET requests and NOT $_POST requests.  So I have recently experienced a brute force attack on one of my accounts and thought it was probably for the best to check my scripts in case I had missed anything (Luckily the attack was unsuccessful).   I came across this script from one of my older accounts:  if(isset($_GET['del'])){     $user_id = $_SESSION['userid'];     $id_pho = $_GET['del'];     $sql = "DELETE FROM new_user_favourites WHERE `user_id` = '$user_id' AND `photo_id` = '$id_pho'";     $conn-&gt;query($sql); }   I thought before I protected this script, that I would give it a bit of a test and found that even if I attempted to cause a problem to this script, using the URL, that the URL added encoded spaces %20 or speech marks %27 and these would not allow the script to process any further code?  For example, I tested:  mysite.co.uk?del='; UPDATE new_users SET account_type='1' WHERE email_address='test@test.com   Which should have sent:  $sql = "DELETE FROM new_user_favourites WHERE `user_id` = '' AND `photo_id` = ''; UPDATE new_users SET account_type='1' WHERE email_address='test@test.com'";   That would have given that user admin privileges to my site. Although because of the encoding, the result in the URL shows as:  mysite.co.uk?del=%27;%20UPDATE%20new_users%20SET%20account_type=%271%27%20WHERE%20email_address=%27test@test.com   And so the query would process like this, and fail:  $sql = "DELETE FROM new_user_favourites WHERE `user_id` = '' AND `photo_id` = '%27;%20UPDATE%20new_users%20SET%20account_type=%271%27%20WHERE%20email_address=%27test@test.com'";   Could this mean that my query is already protected from this kind of attack? Or is there a way around this for people who would wish to destroy my website? I've taken a look online for information about this but there doesn't seem to be anything?
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?
"Notice: Undefined variable", "Notice: Undefined index", and "Notice: Undefined offset" using PHP Looking for old book, SF, artificial world, different zones for different species that visitors "inhabit" Difference between sentences using 'was' and 'being'? What is the meaning of below sentences using was and being?     He committed suicide after he was severely beaten up by four teachers. He committed suicide after being severely beaten up by four teachers. Programmatically delete one entry from one field on one entity What's the proper way to programmatically delete one specific field entry for a multi-entry field from one specific entity? (that's specific fields and specific entities, not field types or instances and entity types)  Here's some possibilities I've looked into which don't work:   Loading the entity with entity_load(), setting the field entry to =null or =array(), then saving with field_attach_update(). It's the closest I've found but it leaves a zombie null field entry in the database which shows up as a blank row on forms until the form is saved and hook_field_is_empty() can kick in (hook_field_is_empty() is configured such that =null or =array() will flag as empty). Loading the entity with entity_load(), unsetting the field entry by key, then saving with field_attach_update(). This seems to do nothing - it seems that Drupal interprets the entry not being there as a sign to not modify it. (strangely I also sometimes get maximum query time expiration timeouts when trying this approach) field_attach_delete() - this is much too blunt: it kills all fields for the entity field_purge_data() - better, but still too blunt: it kills all entries of the field, not specific entries   So to clarify, I've got code that finds (and loads) an entity which has a field that has multiple entries, and finds a specific entry on that field that needs to be removed. I want to remove that entry completely, without touching any other entries or any other fields on the entity. My furnace pilot light keeps going out so I changed the thermocouple. Now the furnace will come on and heat up to the degree set on my thermostat, then the pilot light will go out and the furnace will not come back on.    Could the thermostat be bad and cause the pilot light to go out? How to render a background image in 2.8? I'm trying to "add" an 3D object onto a photo. I have added the photo to the scene in three ways so far, but none of them render (eevee):   Camera > Background Images Empty a. Add > Empty > Image (Empty gets added to current Collection) b. Add > Image > Backround (Empty gets added to Scene Collection)   These all show up in the 3D View and I was able to align the camera and the object so its perspective matches the scene in the photograph. But when I Render the scene, I only see the object, not the background image.  For the latter, it's simple: Empties are not rendered at all. There are few questions about this, since 2.8 has changed how it handles background images. The most popular seems this one (it includes references to others):      But I seem not to be able to find a method to have the background image render.  Another method might be to use the Compositor (Nodes) to Mix or Alpha Over an Image with the Render Layers. But this does not give the same alignment as achieved with the background image (also this requires that the World background does not get rendered (Alpha channel); for Eevee, this can be achieved by checking Film>Transparent).  What other options are there?  Docs: I have successfully transferred "Killing Floor" from my brother's laptop to my own via external hard drive. The problem, now that I have all the files, is that I don't know how to launch the game through Steam. All I did was copy files from his Laptop to the hard drive, then from the hard drive to my laptop, then I put the files in the "Steamapps" folder under "Steam" in my laptops hard drive. So the question is, how do I start up the game through Steam? The 'ok' on the 'Your Answer' dialog on unregistered sites is a bit too high The 'ok' on the 'Your Answer' dialog on unregistered sites is a bit too high:     You can see the top of the k is outside the actual box, increasing the margin-top by 10px in the containing div fixes it. How do I change a user name in Windows 7? $F$ is a finite field of order $q$. What is the size of $\operatorname{GL}_n(F)$ ?  I am reading Dummit and Foote "Abstract Algebra".  The following formula is given:  $(q^n - 1)(q^n - q)\cdots(q^n - q^{n-1})$.  The case for $n = 1$ is trivial.  I understand that for $n = 2$  the first row of the matrix can be any ordered pair of field elements except for $0,0$. and the second row can be any ordered pair of field elements that is not a multiple of the first row.  So for $n = 2$  there are $(q^n - 1)(q^n - q)$ invertible matrices.  For $n\geq 3$, I cannot seem to understand why  the formula works.  I have looked at Sloane's OEIS A002884.  I have also constructed and stared at a list of all $168$ $3\times 3$ invertible matrices over $GF(2)$.  I would most appreciate a concrete and detailed explanation of how say $(2^3 - 1)(2^3 - 2)(2^3 - 2^2)$ counts these $168$ matrices. Boats from Manaus, Brazil to Leticia, Colombia? I've heard of and met a few people who have done this route, and I hope to do it at the end of this year or early next year.  However, the descriptions were mostly sketchy, and I'm wondering if it's a regularly scheduled service, or more ad-hoc.  So I guess the question is, how can I find out which boats go from Manaus to Leticia, and when they go?  Ideally this wouldn't be a tour, but a 'locals' boat. Need to find the recurrence equation for coloring a 1 by n chessboard Ramanujan Summation It seems that under the light of  the following is plausible:  $$1 + {2^{2n - 1}} + {3^{2n - 1}} +  \cdots  =  - \frac{{{B_{2n}}}}{{2n}}(\Re)$$  Alas, I can't really find any concrete definition of Ramanujan Summation. Could someone provide a small explanation? If I push or hit an object in space will it rotate or move along a straight line? If I push or hit an object in space (vacuum and no gravitation) in direction what is not going trough its centroid, will it rotate or move along in straight line?   I expect that on earth it will depend on what is less difficult for the object (rotation or linear movement). So the object will do some kind of combination of both movements (rotating and also moving along the direction of impulse or force).  But how could an object "decide" what to do in space, where is not resistance? Frequency encoding is a widely used technique in Kaggle competitions, and many times proves to be a very reasonable way of dealing with categorical features with high cardinality. I really don't understand why it works.   Does it work in very specific cases where frequencies are correlated with the target or is it more general? What's the rationale behind it? Why have view counters been modified? Yesterday, I have received two : Revival, and Self-Learner. However I was only notified of the Revival badge, because apparently the Self-Learner badge is not considered "".  What badges have their notification suppressed if the user has a 200-rep account somewhere on the Stack Exchange network, i.e. they won't trigger a new item in our achievements dialog? What is Kirito's relationship with the girls of SAO? Prove $-(-a)=a$ using only ordered field axioms Anyone ever seen a "wok adapter" for induction cooktops? In theory a cheap pressed steel wok would work on an , but the "contact patch" for a traditional round bottomed wok would be so small it would be ineffective.  Has anyone seen a steel or cast-iron "wok adapter" with a flat bottom and a concave "bowl" on top to sit the wok in, serving dual purposes of supporting the wok on the stovetop and transferring the induction heat to the wok?  Could anyone speculate if this would this even work? Or wouldn't you be able to get the wok hot enough?