my changes

app/Transaction.php

@@ -1,44 +1,38 @@
-<?php namespace App;
+<?php
+namespace App;
 
 use Illuminate\Database\Eloquent\Model;
 
-class Transaction extends Model {
+class Transaction extends Model
+{
 
-	protected $fillable = [
-		'student_id',
-		'book_id',
-		'borrowed_at',
-		'returned_at',
-		'fines',
-		'status'
-	];
+    protected $fillable = [
+        'student_id',
+        'book_id',
+        'borrowed_at',
+        'returned_at',
+        'fines',
+        'status'
+    ];
 
-	public function student()
-	{
-	
-		return $this->belongsTo('App\Student');
-	
-	}
+    public function student()
+    {
+        return $this->belongsTo('App\Person', 'student_id');
+    }
 
-	public function book()
-	{
-	
-		return $this->belongsTo('App\Book');
-	
-	}
+    public function book()
+    {
+        //model, foreign key in tsis model, primary key of relation
+        return $this->belongsTo('App\Book', 'book_id', 'id');
+    }
 
-	public function scopeNotReturnedYet($query)
-	{
-		
-		return $query->where('status', 0);
-
-	}
-
-	public function scopeReturned($query)
-	{
-		
-		return $query->where('status', 1);
-
-	}
+    public function scopeNotReturnedYet($query)
+    {
+        return $query->where('status', 0);
+    }
 
+    public function scopeReturned($query)
+    {
+        return $query->where('status', 1);
+    }
 }