In continuation:
TOracleQuery.SqlText :=
SELECT
b.comments,
a.data_type,
a.data_default,
a.nullable,
a.column_name
FROM
all_tab_columns a,
all_col_comments b
WHERE
UPPER(a.table_name) = UPPER(:TableName)AND
(b.table_name = a.table_name) AND
(b.column_name = a.column_name)...