Array of column names whose value change causes resaving of the external columns.

Gets or sets a transformation function which is called when the data is retrieved from the external storage. Can be used for example to remove default directives to layout code.

Gets or sets a transformation function which is called when the data is saved to the external storage. Can be used for example to add default directives to layout code.

Gets or sets the callback function which returns base path of the object for given column name.

Storage provider to use. If not set, the default storage provider is used.

Indicates whether to store data also in DB.

Gets or sets the name of the settings key which indicates whether to store column in external storage or not.