Lean Mapper Query is a concept of a query object for Lean Mapper library which helps to build complex queries using automatic joins (idea taken from NotORM library). Look at the suggested base classes. For Czech documentation have a look at the wiki.
- it behaves as an
SQLpreprocessor, hence most SQL expressions are available - automatic joins using dot notation (
@book.tags.name) - ability to query both repositories or entities
- support for implicit filters
It can be installed via Composer.
composer require mbohuslavek/leanmapper-query:@dev
Suppose we have following repositories:
class BaseRepository extends LeanMapper\Repository
{
public function find(IQuery $query)
{
$this->createEntities($query
->applyQuery($this->createFluent(), $this->mapper)
->fetchAll()
);
}
}
class BookRepository extends BaseRepository
{
}and following entities:
/**
* @property int $id
* @property string $name
*/
class Tag extends LeanMapper\Entity
{
}
/**
* @property int $id
* @property Author $author m:hasOne
* @property Tag[] $tags m:hasMany
* @property DateTime $pubdate
* @property string $name
* @property bool $available
*/
class Book extends LeanMapper\Entity
{
}
/**
* @property int $id
* @property string $name
* @property Book[] $books m:belongsToMany
*/
class Author extends LeanMapper\Entity
{
}We build a query:
$query = new LeanMapperQuery\Query;
$query->where('@author.name', 'Karel');Now, if we want to get all books whose author's name is Karel, we have to do this:
$bookRepository = new BookRepository(...);
$books = $bookRepository->find($query);Database query will look like this:
SELECT [book].*
FROM [book]
LEFT JOIN [author] ON [book].[author_id] = [author].[id]
WHERE ([author].[name] = 'Karel')You can see it performs automatic joins via dot notation. It supports all types of relationships which are known to Lean Mapper.
It is very easy to use SQL functions. We can update query like this:
$query->where('DATE(@pubdate) > %d', '1998-01-01');
$books = $bookRepository->find($query);and change the database query into following:
SELECT [book].*
FROM [book]
LEFT JOIN [author] ON [book].[author_id] = [author].[id]
WHERE ([author].[name] = 'Karel') AND (DATE([book].[pubdate]) > '1998-01-01')You can extend Query and define own methods.
class BookQuery extends LeanMapperQuery\Query
{
public function restrictAvailable()
{
$this->where('@available', TRUE)
->orderBy('@author.name');
return $this;
}
}
/////////
$query = new BookQuery;
$query->restrictAvailable();
$books = $this->bookRepository->find($query);It is also possible to query an entity property (currently only those properties with BelongsToMany or HasMany relationships). Let's build BaseEntity:
class BaseEntity extends LeanMapperQuery\Entity
{
protected static $magicMethodsPrefixes = array('find');
protected function find($field, IQuery $query)
{
$entities = $this->queryProperty($field, $query);
return $this->entityFactory->createCollection($entities);
}
}
/*
* ...
*/
class Book extends BaseEntity
{
}Note that BaseEntity extends LeanMapperQuery\Entity to make the following possible.
We have defined the find method as protected because with specifying the method name in $magicMethodsPrefixes property you can query entities like this:
$book; // previously fetched instance of an entity from a repository
$query = new LeanMapper\Query;
$query->where('@name !=', 'ebook');
$tags = $book->findTags($query);The magic method findTags will eventually call your protected method find with 'tags' as the 1 argument.
The resulting database query looks like this:
SELECT [tag].*
FROM [tag]
WHERE [tag].[id] IN (1, 2) AND ([tag].[name] != 'ebook')The first condition in where clause [tag].[id] IN (1, 2) is taken from the entity traversing (tags are queried against this particular book entity's own tags).
If we slightly modify our BaseRepository and BaseEntity we can simplify working with query objects. To achieve this look at the suggested base classes. It makes the following possible.
$books = $bookRepository->query()
->where('@author.name', 'Karel')
->where('DATE(@pubdate) > ?', '1998-01-01')
->find();
// or...
$tags = $book->queryTags()
->where('@name !=', 'ebook')
->find();Copyright (c) 2013 Michal Bohuslávek
Licensed under the MIT license.
