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CakePHP Query Builder

CakePHP’s  database Query Builder provides a simple to use fluent interface for creating and operating database queries. It can be used to accomplish most database operations in your application, and works on all supported database systems.


Query builders allow us to create database queries that work with any supported database, without having to worry about differences between SQL implementations in the different database systems.


The CakePHP query builder uses PDO parameter binding to protect your application against SQL injection attacks. There is no need to clean strings being passed as bindings.


For creating a Query object in CakePHP, the easiest way is using find() from a Table object. In CakePHP, queries are lazily evaluated,  which means that they are not evaluated until any of the following actions happens: the query is iterated through a foreach, it’s called first(), all(), toList(), toArray(). 


You can check all the SQL queries that CakePHP is generating, you just need to enable the Database Logging. See here:  https://book.cakephp.org/4/en/orm/database-basics.html#query-logging


Let’s do a few samples using the Query Builder - this is the ER diagram of the database that we will be using for the queries. We have Orders, ProductsUsers and Items that will store the products sold in each order and the quantity sold.

Let’s create some queries using the Query Builder SQL Functions: https://book.cakephp.org/4/en/orm/query-builder.html#using-sql-functions. SQL Functions as part of the Query Builder are abstractions of  some commonly used SQL functions,  and they allow the ORM to choose the specific implementation your application needs based on the Database that is being used. For example, CONCAT is implemented in a different way in MySQL and Postgres, using concat() function will work if you use MySQL or Postgres

 

Imagine we want to build a report of the products sold, including the following:

  1. Display the product in the following format “Products.name - Products.description”.

  2. Total of products sold.

  3. Total of products in stock..

  4. Total amount on sold products.

First, we need to build the Query object using find(), this needs to be done from the Table. $query = Table->find();.

We want to get a report of the products sold and the current stock. Initially, we would need to build a subquery using ItemsTable where the information related to the products sold is present.  Don’t forget to use identifier() when referencing any column. This will tell us  the items sold per product. 

$itemsQuery = $this->Items->find() ->where(['Items.product_id' => $query->identifier('Products.id')]);

Now, let’s build each query needed for the information required:

  1. Let’s start displaying the  product in the following format: “Products.name - Products.description”. Using concat() we could get it:

    $query->select([

                'display_name' => $query->func()->concat([

                    $query->identifier('Products.name'), ' - ',  $query->identifier('Products.description')]),

            ]);

  2. Total of products sold. Using sum() we could get it, we just need to sum Items.quantity per each product,  this  is why we use $itemsQuery and then we sum the quantity per each product.

    $query->select([
      'quantity_sold' => $itemsQuery->select(['sum' => $itemsQuery->func()->sum($query->identifier('Items.quantity'))]),
    ]);

     

  3. To get the income, we need to multiply the Quantity of items  *  Price  and sum all of them. 

      $query->select([
              'income' => $itemsQuery->select(['sum' => $itemsQuery->func()->sum($query->newExpr('Items.quantity * Items.unit_price'))
                ])]);

     

  4. Stock. to get the stock we need to take advantage of the quantity_sold we just got in #2, and subtract it from the real quantity Products.quantity. For getting this, we would need to create a subquery in the FROM clause using the previous queries, and then subtract in the target query something like quantity - quantity_sold.

    $products = $query->cleanCopy()->select([
                'id' => 'ProductDetails.id',
                'price' => 'ProductDetails.price',
                'quantity' => 'ProductDetails.quantity',
                'display_name' => 'ProductDetails.displaye_name',
                'quantity_sold' => 'ProductDetails.quantity_sold',
                'income' => 'ProductDetails.income',
                'stock' => $query->newExpr('ProductDetails.quantity - ProductDetails.quantity_sold'),
            ])->from([
              'ProductDetails' => $query->cleanCopy()->select([
                    'id' => 'Products.id',
                    'price' => 'Products.price',
                    'quantity' => 'Products.quantity',
                    'display_name' => $query->func()->concat([$query->identifier('Products.name'), ' -  ', $query->identifier('Products.description')]),
                  'quantity_sold' => $itemsQuery->select(['sum' => $itemsQuery->func()->sum($query->identifier('Items.quantity'))]),
                  'income' => $itemsQuery->cleanCopy()->select(['sum' => $itemsQuery->func()->sum($query->newExpr('Items.quantity * Items.unit_price'))]),           ])
        ]);

     

Notice that we are using cleanCopy(), this is useful when the same Query object is affected previously by a select(), from() or where clauses, if you run this same example without using cleanCopy() you will get unexpected results. 

The SQL query generated is this:

SELECT ProductDetails.id AS id,
       ProductDetails.price AS price,
       ProductDetails.quantity AS quantity,
       ProductDetails.display_name AS display_name,
       ProductDetails.quantity_sold AS quantity_sold,
       ProductDetails.income AS income,
       (ProductDetails.quantity - ProductDetails.quantity_sold) AS stock
FROM
  (SELECT Products.id AS id,
          Products.price AS price,
          Products.quantity AS quantity,
          (CONCAT(Products.name, :param0, Products.description)) AS display_name,

     (SELECT (SUM(Items.quantity)) AS SUM
      FROM items Items
      WHERE Items.product_id = (Products.id)) AS quantity_sold,

     (SELECT (SUM(Items.quantity * Items.unit_price)) AS SUM
      FROM items Items
      WHERE Items.product_id = (Products.id)) AS income
   FROM products Products) ProductDetails


CakePHP QueryBuilder gives a ton of possibilities to create queries with clean and robust code. So go play with it and enjoy!

 

Latest articles

CakePHP Upgrade to 4 - Piece by Piece

Let's imagine you have a huge application in CakePHP 2.x (or 1.x) and you're planning to upgrade to the latest CakePHP 4.x. After doing some estimations, you realize the upgrade process is out of your scope, because you don't have the budget or developer availability to do it in 1 shot. At this point, some companies would abort the upgrade and keep working on 2.x for "some more time" until "this last release is delivered" or until "budget is available next fall", digging deeper and deeper into the rabbit hole…   There's an alternative you could follow if this is your case: proceed with the upgrade of a smaller portion of your application and let the 2 versions coexist for some time.   Warning: This is NOT for every project or company. Please carefully think about this decision as it has overhead you'll need to handle.   So, if your application has a portion that could be extracted, with a small set of dependencies from other areas of your application, or if you are creating a new feature with a limited set of dependencies with the rest of your application, this approach would be good for you.   In order to allow both applications to coexist, we are going to keep the CakePHP 1.x application as the main one, and use CakePHP 4.x as a subfolder inside of the first one. It's important to note that in order to share sessions between both applications you'll need to use a storage you can actually share, like database or cache based sessions (redis, etc). Then, you can use a configuration like this one (see below) to add a new upstream to handle your new application. Note: the upstream could be located in another server of your network, using a different PHP version etc.   We've used nginx as an example, but you can use the same approach in other web servers like Apache.   In our example we're going to use all paths starting with /api  to be managed by our new CakePHP 4.x application. upstream cake4 {      # Note this could be any server/port in your network where the cake4 application is installed          server 127.0.0.1:9090; }   # This is our CakePHP 2.x server server {     server_name example.com;       root   /var/virtual/example.com/app/webroot;     index index.php;       # All requests /api are forwarded to our CakePHP 4.x application location /api {         proxy_pass http://cake4;             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;         proxy_set_header Host $host;             proxy_http_version 1.1;         proxy_set_header Upgrade $http_upgrade;             proxy_set_header Connection "Upgrade";     }       location / {             try_files $uri $uri/ /index.php?$args;     }       location ~ \.php$ {           try_files $uri =404;           include fastcgi_params;                fastcgi_pass unix:/run/php/php7.4-fpm.sock;           fastcgi_index index.php;             fastcgi_intercept_errors on;         fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;     } }   # This is our CakePHP 4.x server server {     listen 9090;     server_name example.com;       root   /var/virtual/cake4-example.com/webroot;     index index.php;       location / {         try_files $uri $uri/ /index.php?$args;     }       location ~ \.php$ {         try_files $uri =404;             include fastcgi_params;         fastcgi_pass unix:/run/php/php7.4-fpm.sock;             fastcgi_index index.php;         fastcgi_intercept_errors on;             fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;     } }   As you can see, we have 3 blocks defined in our configuration file:

  • upstream cake4 {...} to forward requests to the CakePHP 4.x application
  • server {... 2.x ...} using a location /api to forward all these calls to the CakePHP 4.x server
  • server {... 4.x ...} using a specific port (9090) to handle requests in CakePHP 4.x
  Using this approach, you can break your application into 2 parts, and start moving features by path to CakePHP 4. You'll need to handle the changes in 2 projects for a while, and pay this overhead,  but this could be better to maintain than a CakePHP 2.x application sitting on an old PHP version. Happy baking!  

Dependency Injection with CakePHP

Dependency Injection is some of the bigger buzzwords in PHP frameworks.  Historically, CakePHP application logic didn’t support that, until the version 4.2 was released last December. You can do that on your own and have a few plugins for that. This is a new chapter of the framework, let's see how to bake it.  

Use Case

First, let’s talk about a classic Use case on real applications. Our application will include an address form, such as the shipping address for an online order, or provide information about User, Company, etc. Autocomplete can help users supply the details.   We will use the Geocoding API from Google Maps Platform, making a HTTP request for API with json output format and address parameter: https://maps.googleapis.com/maps/api/geocode/json?address=89104&key=****** And here we go, we will get this result:  

Baking a Address Service

After seeing the Use case, all we need on our backend is to make a HTTP request for API and return the JSON result for the frontend to populate related fields.   1. First, let’s exposing our application for accept “.json” requests:   2. Now, we can bake a Address Controller and let’s request an empty result: $ ./bin/cake bake controller Address --actions index   Now our app requests /address.json will return an empty JSON.   3. Let’s bake (manually) the Address Service:   Basically I’m using Cake\Http\Client to make the API request. Also I read Geocode.key from Cake\Core\Configure, we don't want to expose our key on public requests (add the key on config/boostrap.php).   4. Let’s rewrite our Controller:   5. Finally, let’s add our Service on Application.php:   That’s all bakers! Now our endpoint /address.json will support query parameters and return the result of the API request.  

The cost of shiny

I’m here selling an idea and I don't start with the cons. Unfortunately, the Dependency Injection container is an experimental feature that is not API stable yet.  The support is a bit limited, CakePHP will inject services into: constructors of Controllers and Commands and Controller actions. The core team hopefully stabilizes the feature on version 4.3, or at most 4.4. They need your help testing and finding cases, and feedback always is welcome.   I hope this post can be useful for you and your projects.  See you next time!  

Planning For Your Upgrade

Having a successful upgrade implies not only upgrading the code itself, but also identifying the different tasks that will be part of the Upgrade Plan. Making a good plan for an upgrade requires identifying the current status of the application. A good plan is based upon clear, well-defined, and easily understood objectives.   After years of experience with CakeDC making upgrades, migrating applications from CakePHP 1 to CakePHP 4 in all possible combinations, we have noticed there are a set of elements or characteristics that are useful to evaluate and identify before starting the upgrade. Having a clear understanding of these elements will be helpful to define the different tasks that will be included in the Upgrade Plan, and reduce any risk while upgrading and delivering.   Imagine that you want to run a marathon - but before starting any of the thousands of plans you can find on the internet about “How to run a Marathon”, you must know where you are. You could ask yourself:  How many miles per week are you currently running? What is the base training needed to start this program? What is the distance of your longest run in the past 3 weeks? How many days per week do you have available to exercise?, etc. This will help you to choose the plan that better fits you. It’s important to identify where you are, where you want to get and how to get where you want.    Wondering how  to evaluate where you are for the Upgrade? Evaluate the status of your application. You could consider the following points as reference:

  • What is your current CakePHP version? 
  • Identify the weaknesses and the strength of the current code by making a code review.
  • Identify the versions of the packages, plugins, libraries that your application is using. 
  • If you are using CakePHP Third Party plugins, figure out if those plugins have already been upgraded.
  • Identify any third party integration and how the upgrade could affect it. 
  • What is the unit test coverage, if any? 
  • Is there any existing documentation?
  • Is there any custom change in the CakePHP core? (I hope there is not!)
  The complexity, time, cost, and resources required to upgrade your application will depend on the status of your application. Once you know where you are, it’s the time to plan how to get where you want.  Let’s talk about this in a future article. In case you are looking for some guidance on preparing your Upgrade Plan, don’t hesitate to contact us, we could help you to identify your current status, define the plan and execute the whole plan for you. We can also work together with your team on the upgrade, helping them understand the upgraded codebase so you can maintain the project with your own team as you did before.  

We Bake with CakePHP