fix bugs. add tests

src/Illuminate/Database/Connection.php

@@ -343,12 +343,12 @@ public function select($query, $bindings = [], $useReadPdo = true)
     }
 
     /**
-     * Run a select statement against the database and returns a cursor.
+     * Run a select statement against the database and returns a generator.
      *
      * @param  string  $query
      * @param  array  $bindings
      * @param  bool  $useReadPdo
-     * @return mixed
+     * @return \Generator
      */
     public function cursor($query, $bindings = [], $useReadPdo = true)
     {
@@ -357,16 +357,19 @@ public function cursor($query, $bindings = [], $useReadPdo = true)
                 return [];
             }
 
-            // For select statements, we'll simply execute the query and return an array
-            // of the database result set. Each element in the array will be a single
-            // row from the database table, and will either be an array or objects.
             $statement = $this->getPdoForSelect($useReadPdo)->prepare($query);
 
-            $statement->setFetchMode($me->getFetchMode());
+            if ($me->getFetchMode() === PDO::FETCH_CLASS) {
+                $statement->setFetchMode($me->getFetchMode(), 'StdClass');
+            } else {
+                $statement->setFetchMode($me->getFetchMode());
+            }
 
             $statement->execute($me->prepareBindings($bindings));
 
-            return $statement;
+            while ($record = $statement->fetch()) {
+                yield $record;
+            }
         });
     }
 

src/Illuminate/Database/Eloquent/Builder.php

@@ -304,29 +304,16 @@ public function firstOrFail($columns = ['*'])
     }
 
     /**
-     * Traverses through a result set using a cursor.
+     * Get a generator for the given query.
      *
-     * @return void
+     * @return \Generator
      */
     public function cursor()
     {
         $builder = $this->applyScopes();
 
-        $statement = $builder->query->cursor();
-
-        while ($row = $statement->fetch()) {
-            // On each result set, we will pass them to the callback and then let the
-            // developer take care of everything within the callback, which allows us to
-            // keep the memory low for spinning through large result sets for working.
-
-            if ($row === false) {
-                return;
-            }
-
-            //Hydrate and yield an Eloquent Model
-            $model = $this->model->newFromBuilder($row);
-
-            yield $model;
+        foreach ($builder->query->cursor() as $record) {
+            yield $this->model->newFromBuilder($record);
         }
     }
 

src/Illuminate/Database/Query/Builder.php

@@ -1693,15 +1693,19 @@ protected function restoreFieldsForCount()
     }
 
     /**
-     * Execute the query as a "select" statement.
+     * Get a generator for the given query.
      *
-     * @return mixed
+     * @return \Generator
      */
     public function cursor()
     {
-        $results = $this->connection->cursor($this->toSql(), $this->getBindings(), ! $this->useWritePdo);
+        if (is_null($this->columns)) {
+            $this->columns = ['*'];
+        }
 
-        return $results;
+        return $this->connection->cursor(
+            $this->toSql(), $this->getBindings(), ! $this->useWritePdo
+        );
     }
 
     /**

tests/Database/DatabaseEloquentIntegrationTest.php

@@ -112,6 +112,21 @@ public function testBasicModelRetrieval()
         $collection = EloquentTestUser::find([1, 2, 3]);
         $this->assertInstanceOf('Illuminate\Database\Eloquent\Collection', $collection);
         $this->assertEquals(2, $collection->count());
+
+        $models = EloquentTestUser::where('id', 1)->cursor();
+        foreach ($models as $model) {
+            $this->assertEquals(1, $model->id);
+        }
+
+        $records = DB::table('users')->where('id', 1)->cursor();
+        foreach ($records as $record) {
+            $this->assertEquals(1, $record->id);
+        }
+
+        $records = DB::cursor('select * from users where id = ?', [1]);
+        foreach ($records as $record) {
+            $this->assertEquals(1, $record->id);
+        }
     }
 
     public function testBasicModelCollectionRetrieval()