# Class yii\db\ForeignKeyConstraint

Inheritance | yii\db\ForeignKeyConstraint » yii\db\Constraint » yii\base\BaseObject
Implements | yii\base\Configurable
Available since version | 2.0.13
Source Code | https://github.com/yiisoft/yii2/blob/master/framework/db/ForeignKeyConstraint.php

ForeignKeyConstraint represents the metadata of a table `FOREIGN KEY` constraint.

## Public Properties

Hide inherited properties

Property | Type | Description | Defined By
--- | --- | --- | ---
$columnNames | string[]|null | List of column names the constraint belongs to. | yii\db\Constraint
$foreignColumnNames | string[] | List of referenced table column names. | yii\db\ForeignKeyConstraint
$foreignSchemaName | string|null | Referenced table schema name. | yii\db\ForeignKeyConstraint
$foreignTableName | string | Referenced table name. | yii\db\ForeignKeyConstraint
$name | string|null | The constraint name. | yii\db\Constraint
$onDelete | string|null | Referential action if rows in a referenced table are to be deleted. | yii\db\ForeignKeyConstraint
$onUpdate | string|null | Referential action if rows in a referenced table are to be updated. | yii\db\ForeignKeyConstraint

## Public Methods

Hide inherited methods

Method | Description | Defined By
--- | --- | ---
__call() | Calls the named method which is not a class method. | yii\base\BaseObject
__construct() | Constructor. | yii\base\BaseObject
__get() | Returns the value of an object property. | yii\base\BaseObject
__isset() | Checks if a property is set, i.e. defined and not null. | yii\base\BaseObject
__set() | Sets value of an object property. | yii\base\BaseObject
__unset() | Sets an object property to null. | yii\base\BaseObject
canGetProperty() | Returns a value indicating whether a property can be read. | yii\base\BaseObject
canSetProperty() | Returns a value indicating whether a property can be set. | yii\base\BaseObject
className() | Returns the fully qualified name of this class. | yii\base\BaseObject
hasMethod() | Returns a value indicating whether a method is defined. | yii\base\BaseObject
hasProperty() | Returns a value indicating whether a property is defined. | yii\base\BaseObject
init() | Initializes the object. | yii\base\BaseObject

## Property Details

$foreignColumnNames public property

List of referenced table column names.

public string[] $foreignColumnNames = null
$foreignSchemaName public property

Referenced table schema name.

public string|null $foreignSchemaName = null
$foreignTableName public property

Referenced table name.

public string $foreignTableName = null
$onDelete public property

Referential action if rows in a referenced table are to be deleted.

public string|null $onDelete = null
$onUpdate public property

Referential action if rows in a referenced table are to be updated.

public string|null $onUpdate = null