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Using single-page submission

From: PHP with MySQL Essential Training

Video: Using single-page submission

In the last movie, we created our edit subject form, and we populated it with the values from the current subject. Now, we're ready to see how we process that form. And we're going to do it a little bit differently than we did it last time, because we're going to do the processing on the same page. The form is going to submit to itself. Let's take a look now. Edit subject.php is what we were working with. And let's see where the form in going to submit right now. Right now, it's still submitting to create_subject.php. So we want to change that. So now that it submits to edit_subject.php. And very important. If we're going to update the subject, we need to know what subject we're updating. So we need to just put a little bit here to say subject equals and then the subject id.

Using single-page submission

In the last movie, we created our edit subject form, and we populated it with the values from the current subject. Now, we're ready to see how we process that form. And we're going to do it a little bit differently than we did it last time, because we're going to do the processing on the same page. The form is going to submit to itself. Let's take a look now. Edit subject.php is what we were working with. And let's see where the form in going to submit right now. Right now, it's still submitting to create_subject.php. So we want to change that. So now that it submits to edit_subject.php. And very important. If we're going to update the subject, we need to know what subject we're updating. So we need to just put a little bit here to say subject equals and then the subject id.

Just like we did when we were going to this page. We had a link that went to the edit subject page, and we need to keep track of that subject id all the time. We could put it in our form. We could make a hidden field in the form. Some people like to do that. I prefer to have it in the URL. And that's going to be important, because this page is going to serve a dual purpose, right? It's going to work both ways. So now, up here, we want to do our form processing. So that's going to take place after we make sure that we have a current subject, before we start displaying the form, we're going to do our form processing. Let's, as a starting point, let's grab create subject.

And let's grab what's in here. And let's, we know we're going to need validation functions. That's going to be an addition. Let's add that to the top. And then, let's grab all of this processing that we did up here, all the way down to the bottom. We don't need to close the connection. But everything else before that. We'll copy that. And we're just going to come in here and paste it right there. Now we can go through and start editing it to make it work for our new situation. This is still the same, if it's a submit, then we want to process the form. Don't worry about what it does right now inside there. Let's jump down here, and if it's not, before, we said, well, this is probably a get request, if that was the case, and we redirected them. We don't want to redirect them back to the form. The form is right here below.

So we'll just say well if it wasn't a post, if it wasn't a proper post at least, then we're going to go ahead and redisplay the form again. Right? That works well. Now let's go back up here and take a look again. Processing the form works fine, we've got our validations, I'm actually just going to move these below the validations.. And we'll do is set. There we go. So if it's not empty errors, we were redirecting before back to new subject. We're not going to do that anymore because our page is right below here.

So instead, let's say if errors are empty, then in that case, we want to do all of this form processing. Right. When loaded, validations pass, so we'll perform the updates. So if errors are empty. Then, perform update. And I'm just going to take this final curly quote and move it down here to the end. And then, let's just take all of this, and I can just indent it. There we go. So, if errors are empty, perform the update.

There's one additional field that we're going to need for our update, and that's the ID, right? And we could just use the current subject ID. I'm going to go ahead and just set a new variable, current subject ID. And that's mostly just to remind you that that we need this value, right? Because we need to submit that when we write our update statement. Now, the query that we'll do is different. We're not going to be doing an insert. Instead we're going to be doing an update. What does that look like? Well, you can go back and look at database update in your sandbox if you want a reminder.

I'm just going to paste it in here. Update subjects, set menu name equal to the menu name, position equal to the position, visible equals visible. Make sure you've got spaces at the end of these lines if you're in fact building up this query this way, where id equals, and here's the id. I also added another line, which we hadn't done before, which is called LIMIT 1. Like some of the other examples we've been looking at, it's a good idea if we want to make sure that it's only gona update one subject, that we provide LIMIT 1. It just sort of lets me know that it's only going to do one, it's a safety net for us. So then the query will take place.

Remember though, that we don't just check for the result anymore, we also check to see, did it change something. So mysqli_affected_rose is going to tell us that. It takes the connection as an argument. And if that's equal to one, if we did in fact affect one row, then we'll know that is was success. If was success, let's go ahead and keep this. Let's go ahead and use session, and we'll put in subject created and redirected them to managecontent.php. Just going to go back up here and make sure that I have my session included, I do.

And then let's come back down again. If it's failure though, we're not going to have this session message Instead, we'll just set a plain ol' message. Message equals, subject created, failed. Now, why do that? Well because once we get down here we have that message available to us. We don't have to call this function that retrieves it from our session anymore. Instead we can do something like this. Right, if the message is not empty. Then display the message. Right there, we don't have to pull from the session. And I put a little note here.

Just to remind you of that fact. Now could you put it in the session? You could, the session file is there, and you could read to it and write from it anytime you want. So you absolutely could still put it in the session and then read it back from there. If you wanted to use that same function that we had before. I just wanted to just show you that you don't need to, that we can actually just pass things straight down the page to our form because we're working on the exact same page. Now for our errors, we can display these errors, but we don't need to retrieve them from the session either. So we can just take that away and errors is now going to contain everything we need, without ever going to the session. One thing I'll tell you about it that's sort of nice is that sometimes, after a closing curly brace, like this, you lose track of what they are. You might want to just put, you know, this is end, and then what is it the end of? You come up here and just grab this bit of code, come down here and just paste it in.

Now whenever I see that, I'll know that this curly brace is the ending of if is set post command. So you might want to make a few kinds of those posted notes for yourself. Alright, let's save it, and let's try it all out. Let's go over to Firefox, and here I'm on my edit subjects page, so to begin with, let's go to About Widget Corp. Edit subject, and I'm going to just make it something different. I'll take away the P. I'll click Edit Subject Subject oops subject created, that's the wrong message I forgot to do that, that's going to be subject updated subject updated failed but it did work.

You see here about widget core change click on it we'll go edit subject and now it worked. I'll do it one more time.. Subject updated and it did change here. Now you could go back to this page if you wanted, if that made more sense to you instead of going back to a default page. Let's try setting a postion. Let's try setting position equal to five. Let's edit subject. Look at that. It dropped down here to position number five. We go back, change it from five back to one. Edit subject and now it's back up here at the top.

Now let's try to just get some errors. Let's take it away, let's have no menu name at all. And it's subject. Nope, menu name can't be blank. So we still have our validations, and you'll notice that we're on the same page. It rendered the same page to us immediately afterwards. So that's all there is to it, to this idea of single-page submission, or having two pages for submission. You can do it either way that you'd like. It's really a matter of personal style and preference, whether you want to have it broken up, or whether you want to combine them together. You should try both of them and see which one feels more natural to you.

Show transcript

This video is part of

Image for PHP with MySQL Essential Training
PHP with MySQL Essential Training

131 video lessons · 36066 viewers

Kevin Skoglund
Author

 
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  1. 4m 8s
    1. Welcome
      1m 0s
    2. Using the exercise files
      3m 8s
  2. 15m 6s
    1. What is PHP?
      3m 52s
    2. The history of PHP
      2m 51s
    3. Why choose PHP?
      4m 10s
    4. Installation overview
      4m 13s
  3. 54m 53s
    1. Overview
      2m 33s
    2. Working with Apache Web Server
      6m 56s
    3. Changing the document root
      7m 24s
    4. Enabling PHP
      6m 16s
    5. Upgrading PHP
      3m 30s
    6. Configuring PHP
      10m 3s
    7. Installing MySQL
      5m 46s
    8. Configuring MySQL
      7m 24s
    9. Text editor
      5m 1s
  4. 31m 25s
    1. Overview
      3m 27s
    2. Installing WampServer
      5m 46s
    3. Finding the document root
      2m 24s
    4. Configuring PHP
      8m 12s
    5. Configuring MySQL
      5m 45s
    6. Text editor
      5m 51s
  5. 19m 12s
    1. Embedding PHP code on a page
      6m 43s
    2. Outputting dynamic text
      5m 55s
    3. The operational trail
      2m 27s
    4. Inserting code comments
      4m 7s
  6. 1h 18m
    1. Variables
      7m 50s
    2. Strings
      4m 38s
    3. String functions
      8m 54s
    4. Numbers part one: Integers
      6m 27s
    5. Numbers part two: Floating points
      5m 25s
    6. Arrays
      10m 0s
    7. Associative arrays
      6m 37s
    8. Array functions
      6m 33s
    9. Booleans
      3m 50s
    10. NULL and empty
      5m 15s
    11. Type juggling and casting
      8m 27s
    12. Constants
      4m 43s
  7. 27m 37s
    1. If statements
      6m 0s
    2. Else and elseif statements
      4m 16s
    3. Logical operators
      7m 30s
    4. Switch statements
      9m 51s
  8. 42m 15s
    1. While loops
      8m 41s
    2. For loops
      5m 59s
    3. Foreach loops
      8m 16s
    4. Continue
      8m 28s
    5. Break
      4m 8s
    6. Understanding array pointers
      6m 43s
  9. 37m 25s
    1. Defining functions
      8m 25s
    2. Function arguments
      5m 32s
    3. Returning values from a function
      7m 33s
    4. Multiple return values
      4m 53s
    5. Scope and global variables
      6m 2s
    6. Setting default argument values
      5m 0s
  10. 20m 18s
    1. Common problems
      3m 47s
    2. Warnings and errors
      8m 36s
    3. Debugging and troubleshooting
      7m 55s
  11. 57m 57s
    1. Links and URLs
      5m 33s
    2. Using GET values
      5m 35s
    3. Encoding GET values
      8m 41s
    4. Encoding for HTML
      9m 26s
    5. Including and requiring files
      7m 40s
    6. Modifying headers
      6m 45s
    7. Page redirection
      6m 43s
    8. Output buffering
      7m 34s
  12. 1h 3m
    1. Building forms
      7m 28s
    2. Detecting form submissions
      5m 59s
    3. Single-page form processing
      7m 57s
    4. Validating form values
      10m 40s
    5. Problems with validation logic
      9m 54s
    6. Displaying validation errors
      7m 23s
    7. Custom validation functions
      6m 28s
    8. Single-page form with validations
      7m 25s
  13. 28m 5s
    1. Working with cookies
      2m 49s
    2. Setting cookie values
      5m 55s
    3. Reading cookie values
      6m 1s
    4. Unsetting cookie values
      4m 51s
    5. Working with sessions
      8m 29s
  14. 48m 39s
    1. MySQL introduction
      6m 43s
    2. Creating a database
      7m 41s
    3. Creating a database table
      7m 42s
    4. CRUD in MySQL
      5m 48s
    5. Populating a MySQL database
      7m 32s
    6. Relational database tables
      6m 40s
    7. Populating the relational table
      6m 33s
  15. 56m 4s
    1. Database APIs in PHP
      4m 51s
    2. Connecting to MySQL with PHP
      7m 45s
    3. Retrieving data from MySQL
      8m 47s
    4. Working with retrieved data
      6m 12s
    5. Creating records with PHP
      6m 58s
    6. Updating and deleting records with PHP
      9m 6s
    7. SQL injection
      3m 5s
    8. Escaping strings for MySQL
      6m 45s
    9. Introducing prepared statements
      2m 35s
  16. 35m 58s
    1. Blueprinting the application
      7m 19s
    2. Building the CMS database
      5m 14s
    3. Establishing your work area
      4m 38s
    4. Creating and styling the first page
      4m 22s
    5. Making page assets reusable
      6m 36s
    6. Connecting the application to the database
      7m 49s
  17. 32m 49s
    1. Adding pages to the navigation subjects
      5m 58s
    2. Refactoring the navigation
      6m 7s
    3. Selecting pages from the navigation
      6m 2s
    4. Highlighting the current page
      5m 26s
    5. Moving the navigation to a function
      9m 16s
  18. 1h 45m
    1. Finding a subject in the database
      9m 48s
    2. Refactoring the page selection
      10m 52s
    3. Creating a new subject form
      6m 55s
    4. Processing form values and adding subjects
      11m 20s
    5. Passing data in the session
      9m 16s
    6. Validating form values
      9m 40s
    7. Creating an edit subject form
      8m 30s
    8. Using single-page submission
      7m 44s
    9. Deleting a subject
      9m 44s
    10. Cleaning up
      10m 37s
    11. Assignment: Pages CRUD
      4m 30s
    12. Assignment results: Pages CRUD
      6m 10s
  19. 39m 26s
    1. The public appearance
      8m 52s
    2. Using a context for conditional code
      11m 37s
    3. Adding a default subject behavior
      6m 9s
    4. The public content area
      5m 51s
    5. Protecting page visibility
      6m 57s
  20. 1h 3m
    1. User authentication overview
      4m 3s
    2. Admin CRUD
      8m 41s
    3. Encrypting passwords
      7m 26s
    4. Salting passwords
      5m 42s
    5. Adding password encryption to CMS
      11m 54s
    6. New PHP password functions
      3m 13s
    7. Creating a login system
      11m 28s
    8. Checking for authorization
      5m 48s
    9. Creating a logout page
      5m 40s
  21. 2m 4s
    1. Next steps
      2m 4s

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