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https://github.com/technicalguru/php-database

A PHP library for accessing databases easily
https://github.com/technicalguru/php-database

data database database-access datamodel datamodels mariadb mariadb-client mariadb-database mariadb-mysql mysql mysql-client mysql-database

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A PHP library for accessing databases easily

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# php-database

A PHP library for accessing databases easily. This library provides a MySQL/MariaDB flavoured database object

that abstracts many daily task in SQL writing, such as quoting, escaping, building SQL statements, WHERE

clauses, error handling and so on.



A [Data Access Object (DAO)](#how-to-use-a-database-access-object-dao) base class is also provided to 

cater for object-relational mapping tasks. The interface will make it easier to find objects by ID, create and update 

them, using special data objects of your own.



Finally, a [Query API](#query-api) is provided to support a flexible writing of restrictions - independant of any SQL dialect.



Version 1.3 is the last major 1.x release and marks the migration release. Traditional SQL writing and Query API are supported

simultanously. However, many traditional SQL methods are marked as deprecated, and they will be removed in release 2.0. 

So you shall migrate to the new Query API early.



# License

This project is licensed under [GNU LGPL 3.0](LICENSE.md). 



# Installation



## By Composer



```sh

composer require technicalguru/database

```



## By Package Download

You can download the source code packages from [GitHub Release Page](https://github.com/technicalguru/php-database/releases)



# How to use the simple Database Layer



## Creating a Database object



Create a configuration array and pass it to the constructor:



```

$config = array(

    'host'        => 'database-hostname',

    'port'        => 3306,

    'dbname'      => 'my-db-name',

    'tablePrefix' => 'test_',

    'user'        => 'user',

    'pass'        => 'password',

);

$db = \TgDatabase\Database($config);

```



Please notice that we provide a table prefix. It is a common practice to prefix all your

tablenames like `test_`. This way, you can keep several "namespaces" in your database.

The prefix will later be added to your query statements whenever you use `#__` in the

table name (see examples below).



Instead of holding the credentials with the configuration, you could use a `TgUtils\Auth\CredentialsProvider`

that holds these data. `Database`will ignore credentials in the config array then.



```

$db = \TgDatabase\Database($config, $credentialsProvider);

```



## Querying objects



```

// Query a list of objects

$arr = $db->queryList('SELECT * FROM #__devtest');



// Querying a single object

$obj = $db->querySingle('SELECT * FROM #__devtest WHERE uid='.$uid);

```



The interface delivers `stdClass` objects by default. However, you can name

your own data class so the data will be populated in such a class:



```

$arr = $db->queryList('SELECT * FROM #__devtest', 'MyNamespace\\MyDataClass');

$obj = $db->querySingle('SELECT * FROM #__devtest WHERE uid='.$uid, 'MyNamespace\\MyDataClass');

```



## Inserting, Updating and Deleting objects



You can insert your own data classes or simply use `stdClass` objects or arrays:



```

// Use a standard class object

$obj        = new stdClass;

$obj->name  = 'test-name';

$obj->email = 'test-email';

$uid = $db->insert('#__devtest', $obj);



// Use your own data class

$obj = new MyNamespace\MyDataClass($initialData);

$uid = $db->insert('#__devtest', $obj);



// Use an array

$arr = array(

   'name'  => 'test-name',

   'email' => 'test-email'

);

$uid = $db->insert('#__devtest', $arr);

```



The `Database` will automatically escape and quote strings that appear as values in your new objects.



Updating your rows is accordingly easy. You will need the table name, the new values (as object or array) and a WHERE condition:



```

// Save all object values

$obj->name = 'Some other name';

$db->update('#__devtest', $obj, 'uid='.$obj->uid);



// Save values from array only

$arr = array('name' => 'Another name');

$db->update('#__devtest', $arr, 'uid='.$uid);

```



If you want to change a single object only, you also can use `updateSingle()` which can give you back the

changed object (as `stdClass`)



```

// Update a single row

$updated = $db->updateSingle('#__devtest', array('name' => 'test-value2'), 'uid='.$uid);

```



And finally you can delete objects. You will need the table name and the WHERE condition:



```

// Delete a single row

$db->delete('#__devtest', 'uid='.$uid);

```



**Remark:** `update()`, `updateSingle()` and `delete()` now support the new [Query API](#query-api) for the

WHERE condition.



# How to use a Database Access Object (DAO)



The low-level `Database` abstraction makes object-relational mappings already  simple. However,

it is still a lot of boilerplate to write, such as table names, WHERE clauses etc. A better way

is provided by the `DAO` object. It simplifies the usage with databases a lot more.



## Creating the DAO



Create a DAO by giving it the `Database` instance and the table name:



```

$dao = \TgDatabase\DAO($db, '#__users');

```



The default constructor as above makes assumptions about your table:



1. It always returns `stdClass` objects.

1. It assumes that your table has an `int auto-increment` primary key that is named `uid`.



However, you can tell `DAO` your specifics:



```

// Uses a specific class for the data

$dao = \TgDatabase\DAO($db, '#__users', 'MyNamespace\\User`);



// Uses a specific class and another primary key attribute

$dao = \TgDatabase\DAO($db, '#__users', 'MyNamespace\\User`, 'id');

```



`DAO` can actually handle non-numeric primary keys. The usage is not recommended though as you need

to create the primary keys yourself.



## Finding objects



Finding objects will be much easier now:



```

// Get user with specific ID

$user = $dao->get(3);



// Find a singe user with a specific email address

$user = $dao->findSingle(array('email' => $email));



// Find all active admin users, ordered by name and email in ascending order

$users = $dao->find(array('group' => 'admin', 'active' => 1), array('name', 'email));

```



**Attention:** This way of describing restrictions is deprecated as of v1.3. `find()` and `findSingle()` now support 

the new Query API. Please read the [Query API](#query-api) chapter.



## Creating, Saving and Deleting objects



```

// Create a new user

$newUser = new stdClass;

$newUser->name     = 'John Doe';

$newUser->email    = '[email protected]';

$newUser->password = '123456';

$newUser->group    = 'webusers';

$newUser->active   = 1;

$newId = $dao->create($newUser);



// Update an existing user

$user = $dao->get($newId);

$user->name = 'Jane Doe';

$dao->save($user);



// Delete a user

$dao->delete($user);

// or

$dao->delete($user->uid);

```



## WHERE clauses in DAO interface



The most simple form of a WHERE clause is the condition itself:



```

$users = $dao->find('group=\'admin\'');

```



But you would need to do the quoting and escaping your self. That's why you can have an array

of all conditions that are concatenated with an `AND`:



```

$users = $dao->find(array('group' => 'admin', 'active' => 1));

```



Or, when an equals (`=`) operation is not what you need:



```

$users $dao->find(array(

    array('group', 'admin', '!='),

    array('active' , 1)

));

```



The default operator is equals (`=`), but you also can use `!=`, `<=`, `>=`, `<`,  `>`, `IN` and `NOT IN`. Latter two

require arrays of values at the second position of the array:



```

$users = $dao->find(array(

    array('group', array('admin'), 'NOT IN'),

    array('active' , 1)

));

```

**Attention:** This way of describing restrictions is deprecated as of v1.3. `find()` and `findSingle()` now support 

the new Query API. Please read the [Query API](#query-api) chapter.



## ORDER clauses in DAO interface



Wherever an ORDER clause can be given, there are two types:



```

// As string

$users = $dao->find('', 'name');

$users = $dao->find('', 'name DESC');

$users = $dao->find('', 'name DESC, email ASC');



// As array

$users = $dao->find('', array('name'));

$users = $dao->find('', array('name DESC'));

$users = $dao->find('', array('name DESC', 'email ASC'));

```



Default order sequence is ascending (`ASC`) if not specified.



**Attention:** This way of describing ordering is deprecated as of v1.3. `find()` and `findSingle()` now support 

the new Query API. Please read the [Query API](#query-api) chapter.



## Extending DAO



It is a good practice not to use `DAO` class directly but derive from it in your project.

That way you can further abstract data access, e.g.



```

class Users extends DAO {



    public function __construct($database) {

        parent::__construct($database, '#__users', 'MyNamespace\\User');

    }

    

    public function findByEmail($email) {

        return $this->findSingle(array('email' => $email));

    }

    

    public function findByDepartment($department, $order = NULL) {

        return $this->find(array('department' => $department), $order);

    }

}   

```



**Attention:** This way of describing restrictions is deprecated as of v1.3. `find()` and `findSingle()` now support 

the new Query API. Please read the [Query API](#query-api) chapter.



## Using Data Objects with DAOs



As mentioned above, you can use your own data classes. There are actually no

restrictions other than the class needs a no-argument constructor. The main

advantage is that this class can have additional methods that have some

logic. You can even define additional attributes that will not be saved in

the database by a DAO. These attributes start with an underscore.



Here is an example:



```

class User {



    // will not be saved

    private $_derivedAttribute;

    

    public function __construct() {

        // You can initialize here

    }

    

    public function getDerivedAttribute() {

        // Have your logic for the attribute here

        // or do something completely different

        

        // Return something

        return $this->_derivedAttribute;

    }

}

```



# Using a DataModel



Finally, we bring everything together. The last thing we need is a central location

for all our `DAO`s. Here comes the `DataModel`:



```

// Setup the model

$model = new \TgDatabase\DataModel($database);

$model->register('users',    $userDAO);

$model->register('products', $productDAO);



// And use it:

$products = $model->get('products')->find();

```



Of course, a better idea is to encapsulate this in your own `DataModel` subclass:



```

class MyDataModel extends \TgDatabase\DataModel {



    public function __construct($database) {

        parent::__construct($database);

    }

    

    protected function init($database) {

        // Optional step: call the parent method (it's empty, but could change)

        parent::init($database);

        

        // No create your DAOs

        $this->register('users',    new UserDAO($database));

        $this->register('products', new ProductDAO($database));

    }

}

```



You only need to implement the `init()` method. Now your final application code looks

much cleaner and can be read easily:



```

// Setup...

$database = new Database($config);

$myModel  = new MyDataModel($database);



// ...and use

$users = $myModel->get('users')->find();

```



Imagine, how much error-proned code you would have to write yourself!



# Using a DaoFactory



The `DataModel` can make use of a `DaoFactory`. Such factory will create DAOs lazily when

requested by your application. Simply create your own instance of such a factory:



```

class MyFactory implements DaoFactory {



    // code omitted for ease of understanding...



    public function createDao($name) {

        switch ($name) {

            case 'users':    return new UserDAO($this->database);

            case 'products': return new ProductDAO($this->database);

        }

        return NULL;

    }

}

```

...and use it...



```

$model = new \TgDatabase\DataModel($database, $myDaoFactory);

```



Now you don't need to overwrite the `init()` method of the `DataModel`.



The use of a `DaoFactory` is recommended when you have many DAOs to manage and your application

usually uses only a fraction of it. It also will decouple your Data Model from the DAOs.



# Query API

Version 1.3 introduces the `Query` which gives you more freedom to express SQL conditions

when searching, updating or deleting objects. It is designed using the Hibernate ORM Criteria template. So much

of the code may appear familiar to you. 



The Query API was created in addition to the Data Model and DAO API and enhances it. So you can still use

the v1.0 way of searching objects while already starting the Query API. However, it is planned to

remove the old API way of describing restrictions and orderings. Watch out for deprecation warning

messages in your log.



**Notice:** Don't worry when you were already using the v1.2 `Criteria` class. It is kept for compatibility

in the 1.x versions (`Criteria` now inherits from `Query`). Starting with v2.0, this interface will be removed.



## Creating a Query

Two ways exist: Creating a `Query` object from the `Database` object, or alternatively from the `DAO`

object:



```

// From Database object

$query = $database->createQuery('#__users');

 

// From DAO object

$query = $userDAO->createQuery();

```



You can define model classes (the objects returned from `SELECT` queries) and aliases when creating a `Query`:



```

// From Database object

$query = $database->createQuery('#__users', 'MyNamespace\\User', 'a');

 

// From DAO object

$query = $userDAO->createQuery('a');

```



As the DAO already knows about the model class, there is no need to mention it when creating from a `DAO`.



The alias is assigned to the underlying table name and will be added automatically when required in restrictions.



## Using Restrictions

Restrictions are expressions that can be used in `WHERE` clauses (and in `JOIN` - see below). The helper

class `Restrictions` is there to create them:



```

$expr1 = Restrictions::eq('name', 'myUsername');

$expr2 = Restrictions::isNotNull('email');

$query->where($expr1, $expr);

```



The most common restrictions are provided: eq, ne, lt, gt, ge, le, like, isNull, isNotNull, between. You can also

use restrictions between two properties:



```

// Check for equalitity of name and email of a user.

$expr = Restrictions::eqProperty('name', 'email');

```



And it is possible to combine restrictions with `and()` and `or()`:



```

$expr = Restrictions::or($expr1, $expr2, $expr3);

```



## Sorting the result

The `Order` class contains three static methods that produce according clauses:



```

// Ascending order

$order1 = \TgDatabase\Order::asc('columnName1');



// Descending order

$order2 = \TgDatabase\Order::desc('columnName2');



// Use plain SQL as given in argument

$order3 = \TgDatabase\Order::sql('ANY_SQL_FUNCTION() ASC');



```



`asc()` and `desc()` will automatically respect aliases and quote the

column names, whereas `sql()` simply uses the string given. 



However, you can use another alias if required:



```

$order2 = \TgDatabase\Order::desc(array('b', 'columnFromJoinedTable'));

```



Finally add these objects to your query:



```

$query->orderBy($order1, $order2);

$query->orderBy($order3);

```



## Modifying the column list: columns and projections

Query will return all columns of the queried table by default. However, you can modify

the column list:



```

// Select myColumn only

$query->select(Projections::property('myColumn'));



// Add another column

$query->select(Projections::property('anotherColumn'));

```



Please notice that the first call to `select` will remove the `*` retrieval

on the query. Any subsequent call will enhance the list. The same result can be

achieved with:



```

$query->setSelect(Projections::property('myColumn'), Projections::property('anotherColumn'));

```



And there are some shortcuts:



```

// Variant 1: flexible argument list

$query1->select(Projections::property('myColumn'), Projections::property('anotherColumn'));



// Variant 2: use #properties() method in Projections

$query1->select(Projections::properties('myColumn', 'anotherColumn'));

```



**Attention:** A call to `setSelect()` or `setProjection()` (deprecated alternative) will NOT remove

the result class definition in the query object as done before. This breaks compatibility with previous versions.

So you need to call `setResultClass(NULL)` to have `stdClass` returned.



## Getting the result

That's the most easiest part:



```

$query->list();

```



You can set restrictions on the result:



```

$query->setFirstResult(10);

$query->setMaxResults(20);

```



Or you expect a single row only:



```

$query->first();

```



## Using Projections

Basic projections - the aggregation of columns of different rows - are available:



```

$proj = Projections::rowCount();

$query->select($proj);

```



You will find projections for: count, distinct, sum, avg, min, max. Please notice that

the returned model class is not reset. You need to call `setResultClass(NULL)` to have 

`stdClass` returned when using projections.



## Subqueries and JOINs

This is most likely the biggest advance in using the Query API. The traditional API methods

were not able to use subqueries when searching for objects depending on other tables.



Let's assume you want to find all books in a database whose author name start with an A. 

The main query comes from books as it is our desired model class to be returned:



```

$query = $bookDAO->createQuery('a');

```



Next we join the authors table and add it to the main query using the respective restriction

to join them properly:



```

$authors     = $authorDAO->createQuery('b');

$restriction = Restrictions::eq(array('a','author'), array('b','uid'));

$query->join($authors, $restriction);

```



And finally we apply the search condition for the author:



```

$authors->where(Restrictions::like('name', 'A%'));

```



Another way of adding subqueries is directly via the main `Query` object:



```

$authors = $booksDAO->createQuery('a');

$authors->createJoin('#__authors', 'b', Restrictions::eq(array('a','author'), array('b','uid')));

$authors->where(Restrictions::like('name', 'A%'));

```



## Updating and deleting multiple objects

The `Query` object can also update and delete objects:



```

// Update

$restrictions = Restrictions::eq('name', 'John Doe');

$updates      = array('comment' => 'This is an unknown author');

$dao->createQuery()->where($restrictions)->update($updates);



// Delete

$restrictions = Restrictions::eq('name', 'Jane Doe');

$dao->createQuery()->where($restrictions)->delete();

```



## GROUP BY and HAVING clauses

The Query API allows to define grouping result sets and restricting the returned result with the HAVING clause:



```

// List the number of books that authors published whose names begin with 'John'

$bookQuery

	->select(Projections::property('author'), Projections::rowCount('cnt'))

	->groupBy(Projections::property('author'))

	->having(Restrictions::like('author', 'John%'))

	->setResultClass(NULL)

	->list();

```



Please notice that using `->count()` on such a query might produce unexpected results. This is still an unresolved issue.



## Useful methods 

You might want to make use of some methods that will ease your code writing:



```

// Query the authors with specific name, starting with 10th row and a max of 20 authors:

$query = $dao->createQuery('a', Restrictions::eq('name', 'John Doe'), Order::asc('uid'), 10, 20);



// Count all records (before limiting the result):

$count  = $query->count(); // returns e.g. 65

$result = $query->list();  // returns 20 objects 



// Count using the DAO

$count  = $dao->count(Restrictions::eq('name', 'John Doe'));

```



## Advantages and Limitations

The Query API further eases searching objects in a database and return model classes, using more

complex expressions and restrictions. You are able to dynamically apply restrictions depending on

the requirements of your front-end users and your application. And you don't need the DAO once you 

created the `Query` object. It is self-contained.



However, some limitations exist:



* Query API supports basic use cases so far (searching objects with basic restrictions, updates, deleting).

* Only MySQL / MariaDB SQL dialect is produced (but can be extended to other dialects easily when you stick to the API).

* A few of the limitations may be ovecome by using the `SqlExpression` and `SqlProjection` classes:



```

// Use a specific restriction not supported

$myExpr = Restrictions::sql('my-sql-fragment');



// Use a specific projection not supported

$myProj = Projections::sql('RANDOM()');

```

  

But feel free to raise an issue (see below) when you need some extension that is not yet supported.



# Contribution

Report a bug, request an enhancement or pull request at the [GitHub Issue Tracker](https://github.com/technicalguru/php-database/issues).