Merge pull request #106 from Icinga/add-belongs-to-one-relation

Introduce `BelongsToOne` relation

src/Relation/BelongsToMany.php

@@ -14,6 +14,9 @@
  */
 class BelongsToMany extends Relation
 {
+    /** @var string Relation class */
+    protected const RELATION_CLASS = HasMany::class;
+
     protected $isOne = false;
 
     /** @var string Name of the join table or junction model class */
@@ -31,9 +34,9 @@ class BelongsToMany extends Relation
     /**
      * Get the name of the join table or junction model class
      *
-     * @return string
+     * @return ?string
      */
-    public function getThroughClass()
+    public function getThroughClass(): ?string
     {
         return $this->throughClass;
     }
@@ -45,7 +48,7 @@ public function getThroughClass()
      *
      * @return $this
      */
-    public function through($through)
+    public function through(string $through): self
     {
         $this->throughClass = $through;
 
@@ -57,7 +60,7 @@ public function through($through)
      *
      * @return Model|Junction
      */
-    public function getThrough()
+    public function getThrough(): Model
     {
         if ($this->through === null) {
             $throughClass = $this->getThroughClass();
@@ -86,7 +89,7 @@ public function getThrough()
      *
      * @return $this
      */
-    public function setThrough($through)
+    public function setThrough(Model $through): self
     {
         $this->through = $through;
 
@@ -110,7 +113,7 @@ public function getTargetForeignKey()
      *
      * @return $this
      */
-    public function setTargetForeignKey($targetForeignKey)
+    public function setTargetForeignKey($targetForeignKey): self
     {
         $this->targetForeignKey = $targetForeignKey;
 
@@ -134,7 +137,7 @@ public function getTargetCandidateKey()
      *
      * @return $this
      */
-    public function setTargetCandidateKey($targetCandidateKey)
+    public function setTargetCandidateKey($targetCandidateKey): self
     {
         $this->targetCandidateKey = $targetCandidateKey;
 
@@ -174,14 +177,16 @@ public function resolve()
             }
         }
 
-        $toJunction = (new HasMany())
+        $junctionClass = static::RELATION_CLASS;
+        $toJunction = (new $junctionClass())
             ->setName($junction->getTableAlias())
             ->setSource($source)
             ->setTarget($junction)
             ->setCandidateKey($this->extractKey($possibleCandidateKey))
             ->setForeignKey($this->extractKey($possibleForeignKey));
 
-        $toTarget = (new HasMany())
+        $targetClass = static::RELATION_CLASS;
+        $toTarget = (new $targetClass())
             ->setName($this->getName())
             ->setSource($junction)
             ->setTarget($target)

src/Relation/BelongsToOne.php

@@ -0,0 +1,13 @@
+<?php
+
+namespace ipl\Orm\Relation;
+
+/**
+ * One-to-one relationship with a junction table
+ */
+class BelongsToOne extends BelongsToMany
+{
+    protected const RELATION_CLASS = HasOne::class;
+
+    protected $isOne = true;
+}

src/Relations.php

@@ -6,6 +6,7 @@
 use ipl\Orm\Exception\InvalidRelationException;
 use ipl\Orm\Relation\BelongsTo;
 use ipl\Orm\Relation\BelongsToMany;
+use ipl\Orm\Relation\BelongsToOne;
 use ipl\Orm\Relation\HasMany;
 use ipl\Orm\Relation\HasOne;
 use IteratorAggregate;
@@ -76,7 +77,7 @@ public function add(Relation $relation)
      * @param string $name        Name of the relation
      * @param string $targetClass Target model class
      *
-     * @return BelongsTo|BelongsToMany|HasMany|HasOne|Relation
+     * @return BelongsTo|BelongsToOne|BelongsToMany|HasMany|HasOne|Relation
      *
      * @throws \InvalidArgumentException If the target model class is not of type string
      */
@@ -164,6 +165,23 @@ public function belongsTo($name, $targetClass)
         return $relation;
     }
 
+    /**
+     * Define a one-to-one relationship with a junction table
+     *
+     * @param string $name        Name of the relation
+     * @param string $targetClass Target model class
+     *
+     * @return BelongsToOne
+     */
+    public function belongsToOne(string $name, string $targetClass): BelongsToOne
+    {
+        $relation = $this->create(BelongsToOne::class, $name, $targetClass);
+
+        $this->add($relation);
+
+        return $relation;
+    }
+
     /**
      * Define a many-to-many relationship
      *

src/Resolver.php

@@ -10,6 +10,7 @@
 use ipl\Orm\Exception\InvalidColumnException;
 use ipl\Orm\Exception\InvalidRelationException;
 use ipl\Orm\Relation\BelongsToMany;
+use ipl\Orm\Relation\BelongsToOne;
 use ipl\Sql\ExpressionInterface;
 use LogicException;
 use OutOfBoundsException;
@@ -564,7 +565,7 @@ public function resolveRelations($path, Model $subject = null)
 
                 $resolvedRelations[$relationPath] = $relation;
 
-                if ($relation instanceof BelongsToMany) {
+                if ($relation instanceof BelongsToMany || $relation instanceof BelongsToOne) {
                     $through = $relation->getThrough();
                     $this->setAlias($through, join('_', array_merge(
                         array_slice($segments, 0, -1),

tests/RelationsTest.php

@@ -6,6 +6,7 @@
 use ipl\Orm\Exception\InvalidRelationException;
 use ipl\Orm\Relation\BelongsTo;
 use ipl\Orm\Relation\BelongsToMany;
+use ipl\Orm\Relation\BelongsToOne;
 use ipl\Orm\Relation\HasMany;
 use ipl\Orm\Relation\HasOne;
 use ipl\Orm\Relations;
@@ -77,31 +78,34 @@ public function testHasOneReturnsOneToOneRelationship()
     {
         $relation = (new Relations())->hasOne('test', TestModel::class);
 
-        /** @noinspection PhpParamsInspection */
         $this->assertInstanceOf(HasOne::class, $relation);
     }
 
     public function testHasManyReturnsOneToManyRelationship()
     {
         $relation = (new Relations())->hasMany('test', TestModel::class);
 
-        /** @noinspection PhpParamsInspection */
         $this->assertInstanceOf(HasMany::class, $relation);
     }
 
     public function testBelongsToReturnsTheInverseRelationship()
     {
         $relation = (new Relations())->belongsTo('test', TestModel::class);
 
-        /** @noinspection PhpParamsInspection */
         $this->assertInstanceOf(BelongsTo::class, $relation);
     }
 
     public function testBelongsToManyReturnsManyToManyRelationship()
     {
         $relation = (new Relations())->belongsToMany('test', TestModel::class);
 
-        /** @noinspection PhpParamsInspection */
         $this->assertInstanceOf(BelongsToMany::class, $relation);
     }
+
+    public function testBelongsToOneReturnsOneToOneRelationship()
+    {
+        $relation = (new Relations())->belongsToOne('test', TestModel::class);
+
+        $this->assertInstanceOf(BelongsToOne::class, $relation);
+    }
 }