Array Char/VarChar Size

Given a defined table as such:

CREATE TABLE array_types (

    data_type_id serial NOT NULL,

    decimal_array decimal(16,2)[] DEFAULT NULL,
    numeric_array numeric(10,2)[] DEFAULT NULL,
    varchar_array varchar(30)[] DEFAULT NULL,
    char_array char(30)[][] DEFAULT NULL,
    PRIMARY KEY  (data_type_id)
);

How do I obtain the precision, decimal places, or character
sizing information from the database. Notice these are array
types.

danap.