Entities: Drupal 8 outline columns, support for long text?

I want to add a column to my custom field, and it should contain long text. The widget might Do you need compatibility with the text format? What is the way to store this data? Is drop the right choice?

$ outline['columns'] = array (
& # 39; name & # 39; => matrix (
& # 39; type & # 39; => & # 39; varchar & # 39 ;,
& # 39; length & # 39; => 255,
)
& # 39; revelation & # 39; => matrix (
& # 39; type & # 39; => & # 39; blob & # 39 ;,
)
& # 39; target_id & # 39; => $ schema['columns']['target_id'],
);