active-record.md 19.8 KB
Newer Older
Alexander Makarov committed
1 2 3
Active Record
=============

Larry Ullman committed
4
Active Record implements the [Active Record design pattern](http://en.wikipedia.org/wiki/Active_record).
Larry Ullman committed
5
The premise behind Active Record is that an individual [[ActiveRecord]] object is associated with a specific row in a database table. The object's attributes are mapped to the columns of the corresponding table. Referencing an Active Record attribute is equivalent to accessing
6
the corresponding table column for that record.
Larry Ullman committed
7

Larry Ullman committed
8
As an example, say that the `Customer` ActiveRecord class is associated with the
Larry Ullman committed
9
`tbl_customer` table. This would mean that the class's `name` attribute is automatically mapped to the `name` column in `tbl_customer`.
Larry Ullman committed
10
Thanks to Active Record, assuming the variable `$customer` is an object of type `Customer`, to get the value of the `name` column for the table row, you can use the expression `$customer->name`. In this example, Active Record is providing an object-oriented interface for accessing data stored in the database. But Active Record provides much more functionality than this.
Larry Ullman committed
11 12

With Active Record, instead of writing raw SQL statements to perform database queries, you can call intuitive methods to achieve the same goals. For example, calling [[ActiveRecord::save()|save()]] would perform an INSERT or UPDATE query, creating or updating a row in the associated table of the ActiveRecord class:
Alexander Makarov committed
13 14 15 16

```php
$customer = new Customer();
$customer->name = 'Qiang';
Qiang Xue committed
17
$customer->save();  // a new row is inserted into tbl_customer
Alexander Makarov committed
18 19 20 21 22 23 24
```


Declaring ActiveRecord Classes
------------------------------

To declare an ActiveRecord class you need to extend [[\yii\db\ActiveRecord]] and
Larry Ullman committed
25
implement the `tableName` method:
Alexander Makarov committed
26 27

```php
Qiang Xue committed
28 29 30
use yii\db\ActiveRecord;

class Customer extends ActiveRecord
Alexander Makarov committed
31 32 33 34 35 36 37 38 39 40 41
{
	/**
	 * @return string the name of the table associated with this ActiveRecord class.
	 */
	public static function tableName()
	{
		return 'tbl_customer';
	}
}
```

Larry Ullman committed
42 43 44 45 46 47 48
The `tableName` method only has to return the name of the database table associated with the class.

Class instances are obtained in one of two ways:

* Using the `new` operator to create a new, empty object
* Using a method to fetch an existing record (or records) from the database

Larry Ullman committed
49
Connecting to the Database
Alexander Makarov committed
50 51
----------------------

Qiang Xue committed
52
ActiveRecord relies on a [[Connection|DB connection]] to perform the underlying DB operations.
Larry Ullman committed
53 54
By default, ActiveRecord assumes that there is an application component named `db` which provides the needed
[[Connection]] instance. Usually this component is configured in application configuration file:
Alexander Makarov committed
55 56

```php
Alexander Makarov committed
57 58 59
return [
	'components' => [
		'db' => [
Alexander Makarov committed
60 61 62 63
			'class' => 'yii\db\Connection',
			'dsn' => 'mysql:host=localhost;dbname=testdb',
			'username' => 'demo',
			'password' => 'demo',
Alexander Makarov committed
64 65 66
		],
	],
];
Alexander Makarov committed
67 68
```

Larry Ullman committed
69
Please read the [Database basics](database-basics.md) section to learn more on how to configure and use database connections.
Alexander Makarov committed
70

Larry Ullman committed
71
Querying Data from the Database
Qiang Xue committed
72
---------------------------
Alexander Makarov committed
73

Qiang Xue committed
74
There are two ActiveRecord methods for querying data from database:
Alexander Makarov committed
75

Qiang Xue committed
76 77
 - [[ActiveRecord::find()]]
 - [[ActiveRecord::findBySql()]]
Alexander Makarov committed
78

Larry Ullman committed
79 80
Both methods return an [[ActiveQuery]] instance, which extends [[Query]], and thus supports
the same set of flexible and powerful DB query methods. The following examples demonstrate some of the possibilities.
Alexander Makarov committed
81 82 83 84

```php
// to retrieve all *active* customers and order them by their ID:
$customers = Customer::find()
Alexander Makarov committed
85
	->where(['status' => $active])
Alexander Makarov committed
86 87 88 89
	->orderBy('id')
	->all();

// to return a single customer whose ID is 1:
Qiang Xue committed
90 91 92
$customer = Customer::find(1);

// the above code is equivalent to the following:
Alexander Makarov committed
93
$customer = Customer::find()
Alexander Makarov committed
94
	->where(['id' => 1])
Alexander Makarov committed
95 96 97 98 99 100 101 102
	->one();

// to retrieve customers using a raw SQL statement:
$sql = 'SELECT * FROM tbl_customer';
$customers = Customer::findBySql($sql)->all();

// to return the number of *active* customers:
$count = Customer::find()
Alexander Makarov committed
103
	->where(['status' => $active])
Alexander Makarov committed
104 105 106
	->count();

// to return customers in terms of arrays rather than `Customer` objects:
Qiang Xue committed
107 108 109 110
$customers = Customer::find()
	->asArray()
	->all();
// each element of $customers is an array of name-value pairs
Alexander Makarov committed
111 112 113 114 115 116 117 118 119 120

// to index the result by customer IDs:
$customers = Customer::find()->indexBy('id')->all();
// $customers array is indexed by customer IDs
```


Accessing Column Data
---------------------

Larry Ullman committed
121
ActiveRecord maps each column of the corresponding database table row to an attribute in the ActiveRecord
Larry Ullman committed
122 123
object. The attribute behaves like any regular object public property. The attribute's name will be the same as the corresponding column
name, and is case-sensitive.
Alexander Makarov committed
124

Larry Ullman committed
125
To read the value of a column, you can use the following syntax:
Alexander Makarov committed
126 127

```php
Larry Ullman committed
128
// "id" and "email" are the names of columns in the table associated with $customer ActiveRecord object
Alexander Makarov committed
129
$id = $customer->id;
Larry Ullman committed
130
$email = $customer->email;
Alexander Makarov committed
131 132
```

Larry Ullman committed
133
To change the value of a column, assign a new value to the associated property and save the object:
Alexander Makarov committed
134 135

```
Larry Ullman committed
136 137 138
$customer->email = 'jane@example.com';
$customer->save();
```
Alexander Makarov committed
139

Larry Ullman committed
140
Manipulating Data in the Database
Qiang Xue committed
141
-----------------------------
Alexander Makarov committed
142

Qiang Xue committed
143
ActiveRecord provides the following methods to insert, update and delete data in the database:
Alexander Makarov committed
144

Qiang Xue committed
145 146 147 148 149 150 151 152 153 154
- [[ActiveRecord::save()|save()]]
- [[ActiveRecord::insert()|insert()]]
- [[ActiveRecord::update()|update()]]
- [[ActiveRecord::delete()|delete()]]
- [[ActiveRecord::updateCounters()|updateCounters()]]
- [[ActiveRecord::updateAll()|updateAll()]]
- [[ActiveRecord::updateAllCounters()|updateAllCounters()]]
- [[ActiveRecord::deleteAll()|deleteAll()]]

Note that [[ActiveRecord::updateAll()|updateAll()]], [[ActiveRecord::updateAllCounters()|updateAllCounters()]]
Larry Ullman committed
155 156
and [[ActiveRecord::deleteAll()|deleteAll()]] are static methods that apply to the whole database
table. The other methods only apply to the row associated with the ActiveRecord object through which the method is being called.
Alexander Makarov committed
157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173

```php
// to insert a new customer record
$customer = new Customer;
$customer->name = 'James';
$customer->email = 'james@example.com';
$customer->save();  // equivalent to $customer->insert();

// to update an existing customer record
$customer = Customer::find($id);
$customer->email = 'james@example.com';
$customer->save();  // equivalent to $customer->update();

// to delete an existing customer record
$customer = Customer::find($id);
$customer->delete();

Qiang Xue committed
174
// to increment the age of ALL customers by 1
Alexander Makarov committed
175
Customer::updateAllCounters(['age' => 1]);
Alexander Makarov committed
176 177
```

Qiang Xue committed
178 179 180
> Info: The `save()` method will either perform an `INSERT` or `UPDATE` SQL statement, depending
  on whether the ActiveRecord being saved is new or not by checking `ActiveRecord::isNewRecord`.

Larry Ullman committed
181 182 183 184 185 186 187 188

Data Input and Validation
-------------------------

ActiveRecord inherits data validation and data input features from [[\yii\base\Model]]. Data validation is called
automatically when `save()` is performed. If data validation fails, the saving operation will be cancelled.

For more details refer to the [Model](model.md) section of this guide.
Alexander Makarov committed
189

Qiang Xue committed
190 191
Querying Relational Data
------------------------
Alexander Makarov committed
192

Larry Ullman committed
193 194
You can use ActiveRecord to also query a table's relational data (i.e., selection of data from Table A can also pull in related data from Table B). Thanks to ActiveRecord, the relational data returned can be accessed like a property of the ActiveRecord object associated with the primary table.

Qiang Xue committed
195 196
For example, with an appropriate relation declaration, by accessing `$customer->orders` you may obtain
an array of `Order` objects which represent the orders placed by the specified customer.
Alexander Makarov committed
197

Qiang Xue committed
198
To declare a relation, define a getter method which returns an [[ActiveRelation]] object. For example,
Alexander Makarov committed
199 200 201 202 203 204

```php
class Customer extends \yii\db\ActiveRecord
{
	public function getOrders()
	{
Luciano Baraglia committed
205
		return $this->hasMany(Order::className(), ['customer_id' => 'id']);
Alexander Makarov committed
206 207 208 209 210 211 212
	}
}

class Order extends \yii\db\ActiveRecord
{
	public function getCustomer()
	{
213
		return $this->hasOne(Customer::className(), ['id' => 'customer_id']);
Alexander Makarov committed
214 215 216 217
	}
}
```

Qiang Xue committed
218 219 220 221
The methods [[ActiveRecord::hasMany()]] and [[ActiveRecord::hasOne()]] used in the above
are used to model the many-one relationship and one-one relationship in a relational database.
For example, a customer has many orders, and an order has one customer.
Both methods take two parameters and return an [[ActiveRelation]] object:
Alexander Makarov committed
222

Qiang Xue committed
223 224 225 226 227 228
 - `$class`: the name of the class of the related model(s). If specified without
   a namespace, the namespace of the related model class will be taken from the declaring class.
 - `$link`: the association between columns from the two tables. This should be given as an array.
   The keys of the array are the names of the columns from the table associated with `$class`,
   while the values of the array are the names of the columns from the declaring class.
   It is a good practice to define relationships based on table foreign keys.
Alexander Makarov committed
229

Qiang Xue committed
230 231
After declaring relations, getting relational data is as easy as accessing a component property
that is defined by the corresponding getter method:
Alexander Makarov committed
232 233

```php
Qiang Xue committed
234 235
// get the orders of a customer
$customer = Customer::find(1);
Alexander Makarov committed
236
$orders = $customer->orders;  // $orders is an array of Order objects
Qiang Xue committed
237 238 239
```

Behind the scene, the above code executes the following two SQL queries, one for each line of code:
Alexander Makarov committed
240

Qiang Xue committed
241 242 243
```sql
SELECT * FROM tbl_customer WHERE id=1;
SELECT * FROM tbl_order WHERE customer_id=1;
Alexander Makarov committed
244 245
```

Qiang Xue committed
246 247 248 249 250 251 252 253
> Tip: If you access the expression `$customer->orders` again, will it perform the second SQL query again?
Nope. The SQL query is only performed the first time when this expression is accessed. Any further
accesses will only return the previously fetched results that are cached internally. If you want to re-query
the relational data, simply unset the existing one first: `unset($customer->orders);`.

Sometimes, you may want to pass parameters to a relational query. For example, instead of returning
all orders of a customer, you may want to return only big orders whose subtotal exceeds a specified amount.
To do so, declare a `bigOrders` relation with the following getter method:
Alexander Makarov committed
254 255 256 257 258 259

```php
class Customer extends \yii\db\ActiveRecord
{
	public function getBigOrders($threshold = 100)
	{
260
		return $this->hasMany(Order::className(), ['customer_id' => 'id'])
Alexander Makarov committed
261
			->where('subtotal > :threshold', [':threshold' => $threshold])
Alexander Makarov committed
262 263 264 265 266
			->orderBy('id');
	}
}
```

Qiang Xue committed
267 268 269 270 271 272 273 274 275 276 277 278 279 280
Remember that `hasMany()` returns an [[ActiveRelation]] object which extends from [[ActiveQuery]]
and thus supports the same set of querying methods as [[ActiveQuery]].

With the above declaration, if you access `$customer->bigOrders`, it will only return the orders
whose subtotal is greater than 100. To specify a different threshold value, use the following code:

```php
$orders = $customer->getBigOrders(200)->all();
```


Relations with Pivot Table
--------------------------

Alexander Makarov committed
281
Sometimes, two tables are related together via an intermediary table called
Qiang Xue committed
282
[pivot table](http://en.wikipedia.org/wiki/Pivot_table). To declare such relations, we can customize
Alexander Makarov committed
283 284 285 286 287 288 289 290 291 292 293
the [[ActiveRelation]] object by calling its [[ActiveRelation::via()]] or [[ActiveRelation::viaTable()]]
method.

For example, if table `tbl_order` and table `tbl_item` are related via pivot table `tbl_order_item`,
we can declare the `items` relation in the `Order` class like the following:

```php
class Order extends \yii\db\ActiveRecord
{
	public function getItems()
	{
294
		return $this->hasMany(Item::className(), ['id' => 'item_id'])
Alexander Makarov committed
295
			->viaTable('tbl_order_item', ['order_id' => 'id']);
Alexander Makarov committed
296 297 298 299 300
	}
}
```

[[ActiveRelation::via()]] method is similar to [[ActiveRelation::viaTable()]] except that
Qiang Xue committed
301 302
the first parameter of [[ActiveRelation::via()]] takes a relation name declared in the ActiveRecord class
instead of the pivot table name. For example, the above `items` relation can be equivalently declared as follows:
Alexander Makarov committed
303 304 305 306 307 308

```php
class Order extends \yii\db\ActiveRecord
{
	public function getOrderItems()
	{
309
		return $this->hasMany(OrderItem::className(), ['order_id' => 'id']);
Alexander Makarov committed
310 311 312 313
	}

	public function getItems()
	{
314
		return $this->hasMany(Item::className(), ['id' => 'item_id'])
Alexander Makarov committed
315 316 317 318 319 320
			->via('orderItems');
	}
}
```


Qiang Xue committed
321 322 323 324
Lazy and Eager Loading
----------------------

As described earlier, when you access the related objects the first time, ActiveRecord will perform a DB query
Alexander Makarov committed
325 326 327 328 329 330 331 332 333 334 335 336
to retrieve the corresponding data and populate it into the related objects. No query will be performed
if you access the same related objects again. We call this *lazy loading*. For example,

```php
// SQL executed: SELECT * FROM tbl_customer WHERE id=1
$customer = Customer::find(1);
// SQL executed: SELECT * FROM tbl_order WHERE customer_id=1
$orders = $customer->orders;
// no SQL executed
$orders2 = $customer->orders;
```

Qiang Xue committed
337
Lazy loading is very convenient to use. However, it may suffer from a performance issue in the following scenario:
Alexander Makarov committed
338 339 340 341 342 343 344 345 346 347 348 349 350 351

```php
// SQL executed: SELECT * FROM tbl_customer LIMIT 100
$customers = Customer::find()->limit(100)->all();

foreach ($customers as $customer) {
	// SQL executed: SELECT * FROM tbl_order WHERE customer_id=...
	$orders = $customer->orders;
	// ...handle $orders...
}
```

How many SQL queries will be performed in the above code, assuming there are more than 100 customers in
the database? 101! The first SQL query brings back 100 customers. Then for each customer, a SQL query
Qiang Xue committed
352
is performed to bring back the orders of that customer.
Alexander Makarov committed
353

Qiang Xue committed
354
To solve the above performance problem, you can use the so-called *eager loading* approach by calling [[ActiveQuery::with()]]:
Alexander Makarov committed
355 356

```php
Qiang Xue committed
357
// SQL executed: SELECT * FROM tbl_customer LIMIT 100;
Alexander Makarov committed
358 359 360 361 362 363 364 365 366 367 368 369 370 371
//               SELECT * FROM tbl_orders WHERE customer_id IN (1,2,...)
$customers = Customer::find()->limit(100)
	->with('orders')->all();

foreach ($customers as $customer) {
	// no SQL executed
	$orders = $customer->orders;
	// ...handle $orders...
}
```

As you can see, only two SQL queries are needed for the same task.


Qiang Xue committed
372
Sometimes, you may want to customize the relational queries on the fly. This can be
Alexander Makarov committed
373 374 375 376 377 378 379 380 381
done for both lazy loading and eager loading. For example,

```php
$customer = Customer::find(1);
// lazy loading: SELECT * FROM tbl_order WHERE customer_id=1 AND subtotal>100
$orders = $customer->getOrders()->where('subtotal>100')->all();

// eager loading: SELECT * FROM tbl_customer LIMIT 10
                  SELECT * FROM tbl_order WHERE customer_id IN (1,2,...) AND subtotal>100
Alexander Makarov committed
382
$customers = Customer::find()->limit(100)->with([
Alexander Makarov committed
383 384 385
	'orders' => function($query) {
		$query->andWhere('subtotal>100');
	},
Alexander Makarov committed
386
])->all();
Alexander Makarov committed
387 388 389 390 391 392 393 394 395
```


Working with Relationships
--------------------------

ActiveRecord provides the following two methods for establishing and breaking a
relationship between two ActiveRecord objects:

Qiang Xue committed
396 397
- [[ActiveRecord::link()|link()]]
- [[ActiveRecord::unlink()|unlink()]]
Alexander Makarov committed
398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448

For example, given a customer and a new order, we can use the following code to make the
order owned by the customer:

```php
$customer = Customer::find(1);
$order = new Order;
$order->subtotal = 100;
$customer->link('orders', $order);
```

The [[link()]] call above will set the `customer_id` of the order to be the primary key
value of `$customer` and then call [[save()]] to save the order into database.


Life Cycles of an ActiveRecord Object
-------------------------------------

An ActiveRecord object undergoes different life cycles when it is used in different cases.
Subclasses or ActiveRecord behaviors may "inject" custom code in these life cycles through
method overriding and event handling mechanisms.

When instantiating a new ActiveRecord instance, we will have the following life cycles:

1. constructor
2. [[init()]]: will trigger an [[EVENT_INIT]] event

When getting an ActiveRecord instance through the [[find()]] method, we will have the following life cycles:

1. constructor
2. [[init()]]: will trigger an [[EVENT_INIT]] event
3. [[afterFind()]]: will trigger an [[EVENT_AFTER_FIND]] event

When calling [[save()]] to insert or update an ActiveRecord, we will have the following life cycles:

1. [[beforeValidate()]]: will trigger an [[EVENT_BEFORE_VALIDATE]] event
2. [[afterValidate()]]: will trigger an [[EVENT_AFTER_VALIDATE]] event
3. [[beforeSave()]]: will trigger an [[EVENT_BEFORE_INSERT]] or [[EVENT_BEFORE_UPDATE]] event
4. perform the actual data insertion or updating
5. [[afterSave()]]: will trigger an [[EVENT_AFTER_INSERT]] or [[EVENT_AFTER_UPDATE]] event

Finally when calling [[delete()]] to delete an ActiveRecord, we will have the following life cycles:

1. [[beforeDelete()]]: will trigger an [[EVENT_BEFORE_DELETE]] event
2. perform the actual data deletion
3. [[afterDelete()]]: will trigger an [[EVENT_AFTER_DELETE]] event


Scopes
------

Qiang Xue committed
449
A scope is a method that customizes a given [[ActiveQuery]] object. Scope methods are static and are defined
Alexander Makarov committed
450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485
in the ActiveRecord classes. They can be invoked through the [[ActiveQuery]] object that is created
via [[find()]] or [[findBySql()]]. The following is an example:

```php
class Customer extends \yii\db\ActiveRecord
{
	// ...

	/**
	 * @param ActiveQuery $query
	 */
	public static function active($query)
	{
		$query->andWhere('status = 1');
	}
}

$customers = Customer::find()->active()->all();
```

In the above, the `active()` method is defined in `Customer` while we are calling it
through `ActiveQuery` returned by `Customer::find()`.

Scopes can be parameterized. For example, we can define and use the following `olderThan` scope:

```php
class Customer extends \yii\db\ActiveRecord
{
	// ...

	/**
	 * @param ActiveQuery $query
	 * @param integer $age
	 */
	public static function olderThan($query, $age = 30)
	{
Alexander Makarov committed
486
		$query->andWhere('age > :age', [':age' => $age]);
Alexander Makarov committed
487 488 489 490 491 492 493 494 495
	}
}

$customers = Customer::find()->olderThan(50)->all();
```

The parameters should follow after the `$query` parameter when defining the scope method, and they
can take default values like shown above.

Qiang Xue committed
496 497 498 499 500 501

Transactional operations
------------------------


When a few DB operations are related and are executed
Alexander Makarov committed
502

503 504
TODO: FIXME: WIP, TBD, https://github.com/yiisoft/yii2/issues/226

Qiang Xue committed
505
,
506
[[afterSave()]], [[beforeDelete()]] and/or [[afterDelete()]] life cycle methods. Developer may come
Qiang Xue committed
507
to the solution of overriding ActiveRecord [[save()]] method with database transaction wrapping or
508 509 510 511 512 513 514 515 516 517 518 519
even using transaction in controller action, which is strictly speaking doesn't seems to be a good
practice (recall skinny-controller fat-model fundamental rule).

Here these ways are (**DO NOT** use them unless you're sure what are you actually doing). Models:

```php
class Feature extends \yii\db\ActiveRecord
{
	// ...

	public function getProduct()
	{
520
		return $this->hasOne(Product::className(), ['product_id' => 'id']);
521 522 523 524 525 526 527 528 529
	}
}

class Product extends \yii\db\ActiveRecord
{
	// ...

	public function getFeatures()
	{
530
		return $this->hasMany(Feature::className(), ['id' => 'product_id']);
531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568
	}
}
```

Overriding [[save()]] method:

```php

class ProductController extends \yii\web\Controller
{
	public function actionCreate()
	{
		// FIXME: TODO: WIP, TBD
	}
}
```

Using transactions within controller layer:

```php
class ProductController extends \yii\web\Controller
{
	public function actionCreate()
	{
		// FIXME: TODO: WIP, TBD
	}
}
```

Instead of using these fragile methods you should consider using atomic scenarios and operations feature.

```php
class Feature extends \yii\db\ActiveRecord
{
	// ...

	public function getProduct()
	{
569
		return $this->hasOne(Product::className(), ['product_id' => 'id']);
570 571 572 573
	}

	public function scenarios()
	{
Alexander Makarov committed
574 575 576 577 578 579
		return [
			'userCreates' => [
				'attributes' => ['name', 'value'],
				'atomic' => [self::OP_INSERT],
			],
		];
580 581 582 583 584 585 586 587 588
	}
}

class Product extends \yii\db\ActiveRecord
{
	// ...

	public function getFeatures()
	{
589
		return $this->hasMany(Feature::className(), ['id' => 'product_id']);
590 591 592 593
	}

	public function scenarios()
	{
Alexander Makarov committed
594 595 596 597 598 599
		return [
			'userCreates' => [
				'attributes' => ['title', 'price'],
				'atomic' => [self::OP_INSERT],
			],
		];
600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628
	}

	public function afterValidate()
	{
		parent::afterValidate();
		// FIXME: TODO: WIP, TBD
	}

	public function afterSave($insert)
	{
		parent::afterSave();
		if ($this->getScenario() === 'userCreates') {
			// FIXME: TODO: WIP, TBD
		}
	}
}
```

Controller is very thin and neat:

```php
class ProductController extends \yii\web\Controller
{
	public function actionCreate()
	{
		// FIXME: TODO: WIP, TBD
	}
}
```
Alexander Makarov committed
629

Qiang Xue committed
630 631 632 633 634 635 636 637 638 639
Optimistic Locks
----------------

TODO

Dirty Attributes
----------------

TODO

Alexander Makarov committed
640 641 642 643
See also
--------

- [Model](model.md)
644
- [[\yii\db\ActiveRecord]]