Models now require a primary key. This is partially to keep the code …

…from becoming a tangled mess, and partially to ensure all Model convenience features work both now and in the future. Closes #1597

system/Exceptions/ModelException.php

@@ -0,0 +1,13 @@
+<?php namespace CodeIgniter\Exceptions;
+
+/**
+ * Model Exceptions.
+ */
+
+class ModelException extends FrameworkException
+{
+	public static function forNoPrimaryKey(string $modelName)
+	{
+		return new static(lang('Database.noPrimaryKey', [$modelName]));
+	}
+}

system/Language/en/Database.php

@@ -25,4 +25,5 @@
    'parseStringFail'       => 'Parsing key string failed.',
    'featureUnavailable'    => 'This feature is not available for the database you are using.',
    'tableNotFound'         => 'Table `{0}` was not found in the current database.',
+   'noPrimaryKey'          => '`{0}` model class does not specify a Primary Key.',
 ];

system/Model.php

@@ -36,6 +36,7 @@
  * @filesource
  */
 
+use CodeIgniter\Exceptions\ModelException;
 use Config\Database;
 use CodeIgniter\I18n\Time;
 use CodeIgniter\Pager\Pager;
@@ -1093,6 +1094,14 @@ protected function builder(string $table = null)
 			return $this->builder;
 		}
 
+		// We're going to force a primary key to exist
+		// so we don't have overly convoluted code,
+		// and future features are likely to require them.
+		if (empty($this->primaryKey))
+		{
+			throw ModelException::forNoPrimaryKey(get_class($this));
+		}
+
 		$table = empty($table) ? $this->table : $table;
 
 		// Ensure we have a good db connection

tests/_support/Database/Migrations/20160428212500_Create_test_tables.php

@@ -88,6 +88,11 @@ public function up()
 
 		//No Primary Key
 		$this->forge->addField([
+			'id'    => [
+				'type'          => 'INTEGER',
+				'constraint'    => 3,
+				$unique_or_auto => true,
+			],
 			'key'   => [
 				'type'       => 'VARCHAR',
 				'constraint' => 40,

tests/_support/Models/SecondaryModel.php

@@ -6,7 +6,7 @@ class SecondaryModel extends Model
 {
 	protected $table = 'secondary';
 
-	protected $primaryKey = null;
+	protected $primaryKey = 'id';
 
 	protected $returnType = 'object';
 

tests/system/Database/Live/ModelTest.php

@@ -247,11 +247,13 @@ public function testFirstWithNoPrimaryKey()
 
 		$this->db->table('secondary')
 				 ->insert([
+					 'id'    => 1,
 					 'key'   => 'foo',
 					 'value' => 'bar',
 				 ]);
 		$this->db->table('secondary')
 				 ->insert([
+					 'id'    => 2,
 					 'key'   => 'bar',
 					 'value' => 'baz',
 				 ]);
@@ -519,14 +521,12 @@ public function testValidationWithSetValidationMessages()
 			'description' => 'some great marketing stuff',
 		];
 
-		$model->setValidationMessages(
-			[
-				'name' => [
-					'required'   => 'Your baby name is missing.',
-					'min_length' => 'Too short, man!',
-				],
-			]
-		);
+		$model->setValidationMessages([
+			'name' => [
+				'required'   => 'Your baby name is missing.',
+				'min_length' => 'Too short, man!',
+			],
+		]);
 
 		$this->assertFalse($model->insert($data));
 
@@ -979,6 +979,7 @@ public function testUpdateNoPrimaryKey()
 
 		$this->db->table('secondary')
 				 ->insert([
+					 'id'    => 1,
 					 'key'   => 'foo',
 					 'value' => 'bar',
 				 ]);
@@ -1103,4 +1104,16 @@ public function testValidationIncludingErrors()
 
 		$this->assertEquals('Minimum Length Error', $model->errors()['name']);
 	}
+
+	/**
+	 * @expectedException        CodeIgniter\Exceptions\ModelException
+	 * @expectedExceptionMessage `Tests\Support\Models\UserModel` model class does not specify a Primary Key.
+	 */
+	public function testThrowsWithNoPrimaryKey()
+	{
+		$model = new UserModel();
+		$this->setPrivateProperty($model, 'primaryKey', '');
+
+		$model->find(1);
+	}
 }

user_guide_src/source/models/model.rst

@@ -14,7 +14,7 @@ instance of the database connection and you're good to go.
 
 ::
 
-        <?php namespace App\Models;
+    <?php namespace App\Models;
 
 	use CodeIgniter\Database\ConnectionInterface;
 
@@ -70,9 +70,9 @@ This ensures that within the model any references to ``$this->db`` are made thro
 connection.
 ::
 
-         <?php namespace App\Models;
+    <?php namespace App\Models;
 
-       use CodeIgniter\Model;
+    use CodeIgniter\Model;
 
 	class UserModel extends Model
 	{
@@ -122,6 +122,9 @@ This is the name of the column that uniquely identifies the records in this tabl
 does not necessarily have to match the primary key that is specified in the database, but
 is used with methods like ``find()`` to know what column to match the specified value to.
 
+.. note:: All Models must have a primaryKey specified to allow all of the features to work
+    as expected.
+
 **$returnType**
 
 The Model's CRUD methods will take a step of work away from you and automatically return