PHP with MySQL Essential Training
Illustration by Don Barnett

Selecting pages from the navigation


PHP with MySQL Essential Training

with Kevin Skoglund

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Video: Selecting pages from the navigation

In this movie, we're going to make our navigation functional. In other words, we're going to make the subjects and pages that right now we just have as a simple list. We're going to turn those into links. And we'll handle the response, when those links are clicked. So, the page that we're working with right now is manage content.PHP. Let's open that up. Here's our navigation. And here's where I've got my subject's menu name outputting. So, what I want to do is just wrap that in an HTML a href tag. And let's do the same thing down here for a page name.
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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. 1h 3m
    1. Overview
      2m 33s
    2. Working with Apache Web Server
      6m 56s
    3. Changing the document root
      7m 24s
    4. Installing to Yosemite NEW
      8m 13s
    5. Enabling PHP
      6m 16s
    6. Upgrading PHP
      3m 30s
    7. Configuring PHP
      10m 3s
    8. Installing MySQL
      5m 46s
    9. Configuring MySQL
      7m 24s
    10. 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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PHP with MySQL Essential Training from
14h 24m Beginner Jun 04, 2013 Updated May 20, 2015

Viewers: in countries Watching now:

PHP is a popular, reliable programming language at the foundation of many smart, data-driven websites. This comprehensive course from Kevin Skoglund helps developers learn the basics of PHP (including variables, logical expressions, loops, and functions), understand how to connect PHP to a MySQL database, and gain experience developing a complete web application with site navigation, form validation, and a password-protected admin area. Kevin also covers the basic CRUD routines for updating a database, debugging techniques, and usable user interfaces. Along the way, he provides practical advice, offers examples of best practices, and demonstrates refactoring techniques to improve existing code.

Topics include:
  • What is PHP?
  • Installing and configuring PHP and MySQL
  • Exploring data types
  • Controlling code with logical expressions and loops
  • Using PHP's built-in functions
  • Writing custom functions
  • Building dynamic webpages
  • Working with forms and form data
  • Using cookies and sessions to store data
  • Connecting to MySQL with PHP
  • Creating and editing database records
  • Building a content management system
  • Adding user authentication
Kevin Skoglund

Selecting pages from the navigation

In this movie, we're going to make our navigation functional. In other words, we're going to make the subjects and pages that right now we just have as a simple list. We're going to turn those into links. And we'll handle the response, when those links are clicked. So, the page that we're working with right now is manage content.PHP. Let's open that up. Here's our navigation. And here's where I've got my subject's menu name outputting. So, what I want to do is just wrap that in an HTML a href tag. And let's do the same thing down here for a page name.

I'll just drop to a new line, a href equals. And, in the A tag, bring that down to a new line as well, right? So now, these are just place holders, I don't have anything here for the href. Where should this link go? When we click on it, what should it do? The page that I want to send it to is the same page, I want it to just reload the manage content page. But, I want it to provide some information in the queries string that it can use. So, the page I'll be using is manage content.php. And then after, that I'm going to have a query string and I'm going to pass the subject ID, subject equals and then whatever its ID is.

Let's do the same thing down here for page real quick. So we'll just do manage content, but this time we're going to set the page ID equal to something. So, what is that something? The subject ID, and let's put in our PHP here. And we know that in the PHP we're going to want to echo something. What do we want to echo? The subject ID. Here it is, right here. Just copy it. Paste it in. Now remember, when we're working with query strings, it's a best practice for us to URL encode those. Now in truth, this is probably a safe value. It's just a simple integer, it comes from the database.

Well, we're still going to go ahead and use URL encode on it anyway. Now, let's do the same thing for the page, I'll just copy all that PHP and drop it right here. But instead of subject ID, it's page ID. Now let's save it, and let's go back over to our manage content page. We'll reload the page. And now when I roll over these, you'll see that they actually do highlight a little bit. They turn a slight white color, and Firefox tells me down at the bottom where the URL will go to. Let's click on a URL. It's fine to do. Let's click on About Widget Corp. And you'll see up here now it says subject equals 1.

On our mission, it says page equals 1. In our history, page equals 2. So, each one of these now is sending an ID up here in the URL string as a value. Letting it know what the current page is. So, all we need to do is read back that value and display it over here on the right-hand side. That's how we're going to respond do it. So in order to do that, let's jump up here to the top, and let's figure out what page is set. So, let's make some PHP code and let's start by saying well, let's check and see if the subject is set. If isset, and we know where that resides, it's in the GET super-global. The key for it is subject.

So if that's set, then, and let's set a variable, selected subject ID is going to be equal to, I'll just paste that in there. That takes care of when our subject is set. That will set a variable if that's set. Then, let's have an else statement, else if. I'm just going to copy this because we're going to do something similar. But instead of subject, we're going to check and see if page has been set. And depending on where the page is set, then we'll set another variable. Selected, page ID equals get and the value page.

Makes sense so far? Alright, let's drop down here to our manage content area. This is everything that's on that right side there, the lighter color, and let's just do simple echo. Echo back, selected, subject ID. And we'll do the same thing but with page ID, and we'll also put a BR tag in between them. Let's go back and let's reload our page. Now there's a problem with this. You may have spotted it, but if not, we're about to find out what it is. Reload the page, and wow, even managed content went away. The rest of the page loaded. So what happened? Well, if we View Source, Web Developer Page Source.

We look down here to see what's going on. We see that Manage Content is in fact there. But when things went crazy, because we have an error. That's what all this is. This is an error. My style sheet kept it from displaying properly. But if we take a look over here, you'll see, it tells us, notice undefined variables, selected subject ID in. And it tells us the line number where that took place. Line number 44. So we're calling selected subject ID, but it hasn't been defined. That's our problem. Let's come back over here, and let's take a look if subject is set. We're setting one variable, but we're not setting the other one. We get to the bottom, we're expecting them both to be defined so we've got a set of default value here.

That's easy enough to do. We'll just say, selected_page_id equals null. Null is perfectly valid to assign to it. This is enough to make PHP not complain. And let's do the same thing here, equals null. And there's one other case that we need to consider. When we first come to this page from our admin page. Go back there real quick and try that out, admin.php. Nothing is selected at the moment. We don't want it to blow up in that case either, so in that case will be default else. And in this case, we're going to grab these two page ID and move that up there.

Selected subject ID. Okay, so now, we have a value for both of these in every case. It's defined in every single case. So let's save it, let's go back, let's reload this page. That works. Clicking on a subject works, clicking on a page works. So, we're able to see different values down here under the managed content. Click around, see the difference. See how the numbers change, they actually jump up and down depending on whether I'm on a subject or a page. Just because I have BR tag in there. Now we have a clickable navigation, and we're able to know what page we're on.

Now, what we're doing with it is not very exciting. We're going to come back and deal with that a little bit later. First, I want us to address another issue. And that is the fact that right now, our Navigation menu doesn't highlight. Which item that we're on. It doesn't stay highlighted. It just highlights it on rollover. Right now, we have no way of knowing what page we're actually on. Our navigation doesn't show us. So, let's see how to highlight the current page in the next movie.

Find answers to the most frequently asked questions about PHP with MySQL Essential Training .

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Q: This course was revised on 6/4/2013. What changed?
A: The old version of this course was 6 years old and it was time for a complete revision, using PHP 5.4. (The tutorials will work with any version of PHP and covers any differences you might encounter). The author has also added updated installation instructions for Mac OS X Mountain Lion and Windows 8. The topics and end project are the same, but the code is slightly different. It also addresses frequently asked questions from the previous version.
Q: This course was updated on 5/20/2015. What changed?
A: We added one movie called "Changing the document root in Yosemite," which helps the Mac installation run more smoothly.
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