Accessing Databases with Object-Oriented PHP
Illustration by Don Barnett

Fetching the result


From:

Accessing Databases with Object-Oriented PHP

with David Powers

Start your free trial now, and begin learning software, business and creative skills—anytime, anywhere—with video instruction from recognized industry experts.

Start Your Free Trial Now

Video: Fetching the result

MySQL improved has five different methods for fetching the results of a select query. The most commonly used is fetch_assoc which gets the next row as an associative array. If you prefer to work with an indexed array, use the fetch_row method. The third method fetch_array offers you a choice. You can have an indexed array, an associative array or both. By default it returns an array that uses both the column name and its number counting from zero as the array keys.
Expand all | Collapse all
  1. 13m 33s
    1. Welcome
      1m 4s
    2. What you should know before watching this course
      2m 8s
    3. Using the exercise files
      4m 56s
    4. Setting SQLite permissions
      1m 11s
    5. A quick primer on using PHP objects
      4m 14s
  2. 10m 12s
    1. Overview of PHP database APIs
      4m 5s
    2. Using prepared statements
      4m 24s
    3. Using transactions
      1m 43s
  3. 48m 57s
    1. Creating a database source name
      2m 3s
    2. Connecting to a database with PDO
      7m 27s
    3. Looping directly over a SELECT query
      3m 49s
    4. Fetching a result set
      8m 3s
    5. Finding the number of results from a SELECT query
      7m 14s
    6. Checking if a SELECT query contains results
      3m 32s
    7. Executing simple non-SELECT queries
      6m 2s
    8. Getting error messages
      7m 17s
    9. Using the quote() method to sanitize user input
      3m 30s
  4. 39m 51s
    1. Binding input and output values
      2m 36s
    2. Using named parameters
      9m 51s
    3. Using question marks as anonymous placeholders
      2m 35s
    4. Passing an array of values to the execute() method
      5m 20s
    5. Binding results to variables
      7m 53s
    6. Executing a transaction
      6m 54s
    7. Closing the cursor before running another query
      4m 42s
  5. 21m 20s
    1. Generating an array from a pair of columns
      2m 44s
    2. Setting an existing object's properties with a database result
      4m 42s
    3. Creating an instance of a specific class with a database result
      6m 1s
    4. Reusing a result set
      7m 53s
  6. 38m 14s
    1. Connecting to a database with MySQLi
      5m 57s
    2. Setting the character set
      1m 57s
    3. Submitting a SELECT query and getting the number of results
      4m 4s
    4. Fetching the result
      7m 35s
    5. Rewinding the result for reuse
      3m 20s
    6. Handling non-SELECT queries
      5m 27s
    7. Getting error messages
      5m 47s
    8. Sanitizing user input with real_escape_string()
      4m 7s
  7. 27m 49s
    1. Initializing and preparing a statement
      4m 17s
    2. Binding parameters and executing a prepared statement
      5m 55s
    3. Binding output variables
      5m 6s
    4. Executing a MySQLi transaction
      7m 5s
    5. Dealing with "commands out of sync" in prepared statements
      5m 26s
  8. 24m 7s
    1. Buffered and unbuffered queries
      4m 19s
    2. Using real_query()
      6m 1s
    3. Freeing resources that are no longer needed
      2m 31s
    4. Submitting multiple queries
      6m 41s
    5. Creating an instance of a class from a result set
      4m 35s
  9. 3m 31s
    1. PDO and MySQLi compared
      3m 31s

please wait ...
Watch the Online Video Course Accessing Databases with Object-Oriented PHP
3h 47m Intermediate Jul 07, 2014

Viewers: in countries Watching now:

Now that PHP has true object-oriented capabilities, it's best practice to access databases using PDO (PHP Data Objects) and MySQLi. These methods produce database-neutral code that works with over a dozen systems, including MySQL, SQL Server, PostgreSQL, and SQLite. Learn how to use PDO and MySQLi to perform basic select, insert, update, and delete operations; improve security with prepared statements; and use transactions to execute multiple queries simultaneously. Author David Powers also covers advanced topics like instantiating custom objects, and compares PDO to MySQLi so you can decide which method is right for you.

Topics include:
  • Connecting to a database with PDO or MySQLi
  • Fetching a result set
  • Executing simple non-SELECT queries
  • Sanitizing user input
  • Binding input and output values
  • Passing an array of values to the execute() method
  • Working with advanced PDO fetch methods
  • Executing a MySQLi transaction
  • Freeing resources that are no longer needed
  • Submitting multiple queries
  • Creating an instance of a class from a result set
Subject:
Developer
Software:
PHP
Author:
David Powers

Fetching the result

MySQL improved has five different methods for fetching the results of a select query. The most commonly used is fetch_assoc which gets the next row as an associative array. If you prefer to work with an indexed array, use the fetch_row method. The third method fetch_array offers you a choice. You can have an indexed array, an associative array or both. By default it returns an array that uses both the column name and its number counting from zero as the array keys.

Consequently each value is listed twice. The fetch_all() method returns the complete result set as a multidimensional array, using the column numbers as the array keys for each row. But you also have the option of using the column names, or both. The final method, fetch_object(), returns the row as an object. If you pass in the name of a class it'll create an instance of that class using the current rows values as its properties.

We'll look at fetch_object in chapter seven but let's see the other four methods in action. This is mysqli_fetch_assoc.php. Which you can find in the chapter 5 05_ 04 folder of the exercise files, where you'll also find the other files used in this video. This page contains the finished code from the previous video. So let's use the fetch_assoc method to display the results.

We need to scroll down to between the two table rows. Insert a new line on line 35, add some php blocker in it. Add a while loop. We'll store each row as row. Then we access the result object and call it's fetch assoc method. The closing brace needs to go after the table row, and what this will do is the result object will return each row as an associative array, which will be stored in row.

We can use that to display it in the table cells. So let's add a PHP block in there. A row, and then the column name. The first one that we want is name. And then we can copy that. And replace the non-breaking space in the next two rows. And then just quickly edit the column names. So the second one called name is meaning and the third one is gender. So, if we save that and then view it in a browser.

There are all the results being displayed. So, we are accessing each row using the column names. So let's take a quick look at fetch row. What I'm going to do is I'm going to make a copy of this page. So save as mysqli_fetch_row.php. I then scroll down to the while loop. And instead of calling the fetch assoc method, we'll call the fetch row method. And this will return each row as an indexed array. So we need to make sure which order we're getting the results from in the database. So let's scroll to the top. Make sure name, meaning, and gender are in that order.

We need to count from 0. So name will be 0. Meaning will be 1. And gender will be 2. If we save that, and view it in a browser. We get exactly the same result as before. So the only difference there is whether you prefer to work with an indexed array or an associative array. Let's see how the fetch array method differs. So, if you open, mysqli_fetch_array. This gives an example of how it works. It submits exactly the same query and stores it as a result, and then the code on lines 13 down to 20 gets the first three rows from that result set using fetch array. The first time, on line 14, fetch array is used in its default mode. Then on line 16, a MySQLI constant, who's being passed as an argument to fetch array.

And similarly on line 18, a different MySQLI constant has been passed as an argument. So, let's take a quick look in the browser, to see what the results are. The first row we get both, we get both numbers of columns and names of columns as the indexes. The second one we get the name, in other words, this is an associative array and in the third one we get the column number, so it's an indexed array.

So if we look back again at this page, the code on line 16 is working exactly the same as if we called fetch assoc except it takes more code to do it. And on line 18, is exactly the same as fetch row again. More code. The only reason you might want to use the fetch array method is if you want to use it in its default state where it returns both column numbers and column names. But most of the time I think you'd prefer to use either fetch assoc or fetch row.

Finally, let's take a look at fetch all. So, open mysql_fetch_all.php. This submits exactly the same query and stores it in a result object. And on line 15, the fetch all method is called. This returns a multi-dimensional array of all the results, not one row at a time, but everything together. So let's take a quick look in a browser to see what this returns. And by default, it returns an indexed array. So, a multidimensional indexed array. However, you do have the choice. You can pass either My SQLI_both or My SQLI_assoc as the argument to change the array type. So let's copy both. And just put it in there as the argument. Save that, and refresh the browser. This time, the multidimensional array contains both the column numbers and the column names as the indices.

And. If we change this to MYSQLI_ASSOC and save it, we get a multidimensional associative array. Using the fetch all method can take up a lot of memory because it builds a multidimensional array from the whole result set. But there's rarely any reason to use it because MySQLI let's you rewind a database result for reuse, and we'll cover that next.

There are currently no FAQs about Accessing Databases with Object-Oriented PHP.

 
Share a link to this course

What are exercise files?

Exercise files are the same files the author uses in the course. Save time by downloading the author's files instead of setting up your own files, and learn by following along with the instructor.

Can I take this course without the exercise files?

Yes! If you decide you would like the exercise files later, you can upgrade to a premium account any time.

Become a member Download sample files See plans and pricing

Please wait... please wait ...
Upgrade to get access to exercise files.

Exercise files video

How to use exercise files.

Learn by watching, listening, and doing, Exercise files are the same files the author uses in the course, so you can download them and follow along Premium memberships include access to all exercise files in the library.


Exercise files

Exercise files video

How to use exercise files.

For additional information on downloading and using exercise files, watch our instructional video or read the instructions in the FAQ .

This course includes free exercise files, so you can practice while you watch the course. To access all the exercise files in our library, become a Premium Member.

* Estimated file size

Are you sure you want to mark all the videos in this course as unwatched?

This will not affect your course history, your reports, or your certificates of completion for this course.


Mark all as unwatched Cancel

Congratulations

You have completed Accessing Databases with Object-Oriented PHP.

Return to your organization's learning portal to continue training, or close this page.


OK
Become a member to add this course to a playlist

Join today and get unlimited access to the entire library of video courses—and create as many playlists as you like.

Get started

Already a member ?

Exercise files

Learn by watching, listening, and doing! Exercise files are the same files the author uses in the course, so you can download them and follow along. Exercise files are available with all Premium memberships. Learn more

Get started

Already a Premium member?

Exercise files video

How to use exercise files.

Ask a question

Thanks for contacting us.
You’ll hear from our Customer Service team within 24 hours.

Please enter the text shown below:

The classic layout automatically defaults to the latest Flash Player.

To choose a different player, hold the cursor over your name at the top right of any lynda.com page and choose Site preferences from the dropdown menu.

Continue to classic layout Stay on new layout
Exercise files

Access exercise files from a button right under the course name.

Mark videos as unwatched

Remove icons showing you already watched videos if you want to start over.

Control your viewing experience

Make the video wide, narrow, full-screen, or pop the player out of the page into its own window.

Interactive transcripts

Click on text in the transcript to jump to that spot in the video. As the video plays, the relevant spot in the transcript will be highlighted.

Learn more, save more. Upgrade today!

Get our Annual Premium Membership at our best savings yet.

Upgrade to our Annual Premium Membership today and get even more value from your lynda.com subscription:

“In a way, I feel like you are rooting for me. Like you are really invested in my experience, and want me to get as much out of these courses as possible this is the best place to start on your journey to learning new material.”— Nadine H.

Thanks for signing up.

We’ll send you a confirmation email shortly.


Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

Keep up with news, tips, and latest courses with emails from lynda.com.

Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

   
submit Lightbox submit clicked
Terms and conditions of use

We've updated our terms and conditions (now called terms of service).Go
Review and accept our updated terms of service.