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Simplifying with a Function

10:24 with Alena Holligan

Now that you’ve had a chance to try this for yourself, I’m going to show you how I solved this challenge. When it comes to programming, there is alway more than one way to do something. If you solved this challenge in a different way than what I am going to show you, GREAT! Now you’ll have two ways to accomplish this and will be able to compare those two options when you run into other similar situations.

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Example Code

functions.php

function genre_array($category = null) {
  $category = strtolower($category);
  include("connection.php");

  try {
    $sql = "SELECT genre, category"
      . " FROM Genres "
      . " JOIN Genre_Categories "
      . " ON Genres.genre_id = Genre_Categories.genre_id ";
    if (!empty($category)) {
      $results = $db->prepare($sql 
          . " WHERE LOWER(category) = ?"
          . " ORDER BY genre");
      $results->bindParam(1,$category,PDO::PARAM_STR);
    } else {
      $results = $db->prepare($sql . " ORDER BY genre");
    }
    $results->execute();
  } catch (Exception $e) {
    echo "bad query";
  }
  $genres = array();
  while ($row = $results->fetch(PDO::FETCH_ASSOC)) {
      $genres[$row["category"]][] = $row["genre"];
  }
  return $genres;
}

suggest.php

<select name="genre" id="genre">
    <option value="">Select One</option>
        <?php
        $genre_array = genre_array();
        foreach ($genre_array as $category=>$options) {
          echo "<optgroup label=\"$category\">";
          foreach ($options as $option) {
            echo "<option value=\"$option\"";
            if (isset($genre) && $genre==$option) {
              echo " selected";
            }
            echo ">$option</option>";
          }
          echo "</optgroup>";
        }
        ?>
</select>

Now that you've had a chance to try this for yourself, 0:00

I'm going to show you how I solved this challenge. 0:02

When it comes to programming, there's always more than one way to do something. 0:06

If you solve this challenge in a different way than what 0:10

I'm going to show you, great. 0:13

Now you'll have two ways to accomplish this. 0:16

And, we'll be able to compare those two options when you run into another 0:18

similar situation. 0:22

>> In the functions.php file, 0:23

I'm going to start by writing a new function to retrieve an array of genres. 0:26

Let's add this just after our single item array. 0:32

Then we can reference that function when we needed. 0:34

We'll name this genre_array. 0:44

For this challenge we want to pull all genre group by category. 0:50

But let's make this function a little more flexible. 0:54

We may want to use this to retrieve a single category. 0:56

So let's set up an optional parameter for category. 1:00

Then, if we want to select only the genre in a certain category, we can. 1:10

It's helpful to write things in such a way that their use can be extended 1:15

in the future. 1:18

This helps you out later on. 1:19

We want to make sure that our category variable is lowercase. 1:22

So let's add that to the top of our function. 1:25

Next, we need to include our connection.php file. 1:38

Now we're ready to start our try catch block. 1:48

We'll start with the sequel variable. 1:52

This will be our main select. 1:58

We'll select genre and 2:00

category from genres. 2:08

We also need to join this. 2:15

We'll join our genre's category on genre_id. 2:27

Now let's get the results for all the genre. 2:41

We also want to order by genre, so let's add that here. 2:48

When concatenating a string make sure there are spaces where needed. 2:56

You can always add more spaces without causing an issue, but 3:00

no spaces will run words together and cause things not to work. 3:04

Finally we need to execute our results. 3:10

Now, we can add our conditional for the category. 3:18

If (!empty($category)) {. 3:21

We'll duplicate this prepare line for our else statement. 3:30

Now we can add our where clause. 3:39

We now need our bind statement to replace our placeholder with our category. 4:02

This is a string, so we'll use the string-filter. 4:21

We also have our else. 4:24

And our execute is down below our else. 4:26

So we're ready to finish off our try and at our catch block. 4:29

Now I want to create an associative array. 4:48

With the key being the category and 4:50

the value set to an inner array of category genre. 4:53

We'll use the fetch within a while loop so we can format the results the way we want. 4:57

Let's start by initializing our array. 5:02

Then we can start the while loop. 5:11

We'll use our row to pull our category. 5:36

This will be our key. 5:44

Now we need to add an inner array. 5:46

This will add each genre to the appropriate category. 5:55

We're now ready to return our genres. 5:59

Now we can use this function to build our drop down. 6:06

So let's open suggest.php. 6:09

First we need to include our function.php file. 6:13

Now we're ready to modify our genre drop down. 6:24

Let's remove all the items except one opt group and one option. 6:34

We'll use those as templates. 6:40

Before our optgroup, let's open a php block. 6:59

We'll move this back a little. 7:07

Now let's start by creating a genre array. 7:12

We'll use our genre_array function. 7:18

These can have the same name because one is a variable and one is a function. 7:23

Next we'll start looping through the array with a for 7:27

each loop making sure that we grab our key for the category. 7:31

Let's move this back so it's easier to read. 7:51

We can then open our opt group, using our category. 7:56

We need to escape our double quotes and change books to category. 8:06

We need another for each loop to loop through the options. 8:17

This time we don't care about the key. 8:20

Now we can use option in our option template. 8:28

We don't need to open a php block, because we're already in a php block. 8:45

So let's close this line and we're ready for our if. 8:50

Instead of action here. 8:57

We also want to use our option. 8:59

So if our genre is set and 9:02

if genre equals our option then we want to show this as selected. 9:04

We're ready to close our inner for each. 9:25

We can then end our opt group. 9:30

And finally we'll finish our outer for each and end our php block. 9:39

Now let's preview this in the browser. 9:49

Our genre drop down is there and if we choose a genre and 9:56

hit send our genre is selected. 10:01

Fantastic. 10:05

We've moved from all this code 10:07

to this code using a function that connects to the database. 10:09

Although this didn't change the functionality of our site, 10:14

now when we add or 10:17

update genres in our database, our suggest form will be updated automatically. 10:18

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