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README.md

@@ -47,4 +47,205 @@ in Yii1. You may attach it to your model class in the following way:
 ```php
 <?php
 
+use CActiveRecord;
+use yii1tech\ar\softdelete\SoftDeleteBehavior;
+
+class Item extends CActiveRecord
+{
+    public function behaviors()
+    {
+        return [
+            'softDeleteBehavior' => [
+                'class' => SoftDeleteBehavior::class,
+                'softDeleteAttributeValues' => [
+                    'is_deleted' => true,
+                ],
+            ],
+        ];
+    }
+}
 ```
+
+There are 2 ways of "soft" delete applying:
+- using `softDelete()` separated method
+- mutating regular `delete()` method
+
+Usage of `softDelete()` is recommended, since it allows marking the record as "deleted", while leaving regular `delete()`
+method intact, which allows you to perform "hard" delete if necessary. For example:
+
+```php
+<?php
+
+$id = 17;
+$item = Item::model()->findByPk($id);
+$item->softDelete(); // mark record as "deleted"
+
+$item = Item::model()->findByPk($id);
+var_dump($item->is_deleted); // outputs "true"
+
+$item->delete(); // perform actual deleting of the record
+$item = Item::model()->findByPk($id);
+var_dump($item); // outputs "null"
+```
+
+However, you may want to mutate regular ActiveRecord `delete()` method in the way it performs "soft" deleting instead
+of actual removing of the record. It is a common solution in such cases as applying "soft" delete functionality for
+existing code. For such functionality you should enable `\yii1tech\ar\softdelete\SoftDeleteBehavior::$replaceRegularDelete`
+option in behavior configuration:
+
+```php
+<?php
+
+use CActiveRecord;
+use yii1tech\ar\softdelete\SoftDeleteBehavior;
+
+class Item extends CActiveRecord
+{
+    public function behaviors()
+    {
+        return [
+            'softDeleteBehavior' => [
+                'class' => SoftDeleteBehavior::class,
+                'softDeleteAttributeValues' => [
+                    'is_deleted' => true
+                ],
+                'replaceRegularDelete' => true // mutate native `delete()` method
+            ],
+        ];
+    }
+}
+```
+
+Now invocation of the `delete()` method will mark record as "deleted" instead of removing it:
+
+```php
+<?php
+
+$id = 17;
+$item = Item::model()->findByPk($id);
+$item->delete(); // no record removal, mark record as "deleted" instead
+
+$item = Item::model()->findByPk($id);
+var_dump($item->is_deleted); // outputs "true"
+```
+
+
+## Querying "soft" deleted records <span id="querying-soft-deleted-records"></span>
+
+Obviously, in order to find only "deleted" or only "active" records you should add corresponding condition to your search query:
+
+```php
+<?php
+
+// returns only not "deleted" records
+$notDeletedItems = Item::model()
+    ->findAll('is_deleted = 0');
+
+// returns "deleted" records
+$deletedItems = Item::model()
+    ->findAll('is_deleted = 1');
+```
+
+However, you can use `\yii1tech\ar\softdelete\SoftDeleteQueryBehavior` to facilitate composition of such queries.
+Once being attached ite provides methods similar to scopes for the records filtering using "soft" deleted criteria.
+For example:
+
+```php
+<?php
+
+// Find all "deleted" records:
+$deletedItems = Item::model()->deleted()->findAll();
+
+// Find all "active" records:
+$notDeletedItems = Item::model()->notDeleted()->findAll();
+```
+
+You may easily create listing filter for "deleted" records using `filterDeleted()` method:
+
+```php
+<?php
+
+// Filter records by "soft" deleted criteria:
+$items = Item::model()
+    ->filterDeleted(Yii::app()->request->getParam('filter_deleted'))
+    ->findAll();
+```
+
+This method applies `notDeleted()` scope on empty filter value, `deleted()` - on positive filter value, and no scope (e.g.
+show both "deleted" and "active" records) on negative (zero) value.
+
+> Note: `yii1tech\ar\softdelete\SoftDeleteQueryBehavior1 has been designed to properly handle joins and avoid ambiguous
+column errors, however, there still can be cases, which it will be unable to handle properly. Be prepared to specify
+"soft deleted" conditions manually in case you are writing complex query, involving several tables with "soft delete" feature.
+
+By default `yii1tech\ar\softdelete\SoftDeleteQueryBehavior` composes filter criteria for its scopes using the information from
+`yii1tech\ar\softdelete\SoftDeleteBehavior::$softDeleteAttributeValues`. Thus, you may need to manually configure filter conditions
+in case you are using sophisticated logic for "soft" deleted records marking. For example:
+
+```php
+<?php
+
+use CActiveRecord;
+use yii1tech\ar\softdelete\SoftDeleteBehavior;
+
+class Item extends CActiveRecord
+{
+    public function behaviors()
+    {
+        return [
+            'softDeleteBehavior' => [
+                'class' => SoftDeleteBehavior::class,
+                'softDeleteAttributeValues' => [
+                    'statusId' => 'deleted',
+                ],
+                'deletedCondition' => [
+                    'statusId' => 'deleted',
+                ],
+                'notDeletedCondition' => [
+                    'statusId' => 'active',
+                ],
+            ],
+        ];
+    }
+
+    // ...
+}
+```
+
+> Tip: you may apply a condition, which filters "not deleted" records, to the search query as default, enabling
+  `yii1tech\ar\softdelete\SoftDeleteBehavior::$autoApplyNotDeletedCondition`.
+
+```php
+<?php
+
+use CActiveRecord;
+use yii1tech\ar\softdelete\SoftDeleteBehavior;
+
+class Item extends CActiveRecord
+{
+    public function behaviors()
+    {
+        return [
+            'softDeleteBehavior' => [
+                'class' => SoftDeleteBehavior::class,
+                'softDeleteAttributeValues' => [
+                    'is_deleted' => true,
+                ],
+                'autoApplyNotDeletedCondition' => true,
+            ],
+        ];
+    }
+
+    // ...
+}
+
+$notDeletedItems = Item::model()->findAll(); // returns only not "deleted" records
+
+$allItems = Item::find()
+    ->deleted() // applies "deleted" condition, preventing default one
+    ->findAll(); // returns "deleted" records
+
+$allItems = Item::find()
+    ->filterDeleted('all') // filter all records, preventing default "not deleted" condition
+    ->all(); // returns all records
+```