これは、Oracle SQL Developer からの定義です (表の列ビューに示されているとおり)。
SELECT "COLUMN_NAME", "DATA_TYPE", "NULLABLE", "DATA_DEFAULT", "COLUMN_ID", "COMMENTS" FROM(
select c.column_name, case when data_type = 'CHAR' then data_type||'('||c.char_length||decode(char_used,'B',' BYTE','C',' CHAR',null)||')'
when data_type = 'VARCHAR' then data_type||'('||c.char_length||decode(char_used,'B',' BYTE','C',' CHAR',null)||')'
when data_type = 'VARCHAR2' then data_type||'('||c.char_length||decode(char_used,'B',' BYTE','C',' CHAR',null)||')'
when data_type = 'NCHAR' then data_type||'('||c.char_length||decode(char_used,'B',' BYTE','C',' CHAR',null)||')'
when data_type = 'NUMBER' then
case when c.data_precision is null and c.data_scale is null then 'NUMBER'
when c.data_precision is null and c.data_scale is not null then 'NUMBER(38,'||c.data_scale||')'
else data_type||'('||c.data_precision||','||c.data_SCALE||')' end
when data_type = 'NVARCHAR' then data_type||'('||c.char_length||decode(char_used,'B',' BYTE','C',' CHAR',null)||')'
when data_type = 'NVARCHAR2' then data_type||'('||c.char_length||decode(char_used,'B',' BYTE','C',' CHAR',null)||')'
else data_type end data_type,
decode(nullable,'Y','Yes','No') nullable,
c.DATA_DEFAULT,column_id, com.comments
from sys.Dba_tab_Columns c,
sys.Dba_col_comments com
where c.owner = :OBJECT_OWNER
and c.table_name = :OBJECT_NAME
and c.table_name = com.table_name
and c.owner = com.owner
and c.column_name = com.column_name
order by column_id
)