Oracle Droptyp, wenn existiert

DECLARE
    existing_type number;
BEGIN
    SELECT count(*) into existing_type
    FROM ALL_TYPES
    WHERE TYPE_NAME = 'type_name' AND OWNER = 'schema_name';
    IF existing_type = 1 then
        EXECUTE IMMEDIATE 'DROP TYPE schema_name.type_name';
    END IF;
END;
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