$db public property The DB connection that this command is associated with public yii\db\Connection $db = null

__toString() public method Builds the full string for the column's schema public string __toString ( )

__construct() public method Create a column schema builder instance giving the type and value precision. public void __construct ( $type, $length = null, $db = null, $config = [] )$type string Type of the column. See $type. $length integer|string|array Length or precision of the column. See $length. $db yii\db\Connection The current database connection. See $db. $config array Name-value pairs that will be used to initialize the object properties

unsigned() public method (available since version 2.0.7) Marks column as unsigned. public $this unsigned ( )

unique() public method Adds a UNIQUE constraint to the column. public $this unique ( )

null() public method (available since version 2.0.9) Adds a NULL constraint to the column public $this null ( )

notNull() public method Adds a NOT NULL constraint to the column. public $this notNull ( )

getTypeCategory() protected method (available since version 2.0.8) Returns the category of the column type. protected string getTypeCategory ( )return string A string containing the column type category name.

first() public method (available since version 2.0.8) Adds an FIRST constraint to the column. Note: MySQL, Oracle and Cubrid support only. public $this first ( )

defaultValue() public method Specify the default value for the column. public $this defaultValue ( $default )$default mixed The default value.