ORACLE 테이블 명세 쿼리

-- 테이블 명세가 필요한 데이터베이스로 접근을 하여 아래 쿼리를 실행

SELECT
  A1.TABLE_COMMENTS  TABLE_COMMENTS,
  A1.TABLE_NAME      TABLE_NAME,
  A1.COLUMN_COMMENTS COLUMN_COMMENTS,
  A1.COLUMN_NAME     COLUMN_NAME,
  (CASE WHEN B1.CONSTRAINT_TYPE = 'P'
    THEN 'Y' END)    PK_FLAG,
  (CASE WHEN B1.CONSTRAINT_TYPE = 'R'
    THEN 'Y' END)    FK_FLAG,
  A1.NULL_FLAG,
  A1.DATA_TYPE,
  A1.DATA_LENGTH
FROM (SELECT
        B.COMMENTS    TABLE_COMMENTS,
        A.TABLE_NAME  TABLE_NAME,
        C.COMMENTS    COLUMN_COMMENTS,
        A.COLUMN_NAME COLUMN_NAME,
        (CASE A.NULLABLE
         WHEN 'Y'
           THEN 'Y'
         END)         NULL_FLAG,
        A.DATA_TYPE   DATA_TYPE,
        (CASE
         WHEN A.DATA_TYPE IN('CHAR', 'VARCHAR2')
           THEN '(' || A.DATA_LENGTH || ')'
         WHEN A.DATA_TYPE = 'NUMBER'
              AND A.DATA_SCALE = 0
              AND A.DATA_PRECISION IS NOT NULL
           THEN '(' || A.DATA_PRECISION || ')'
         WHEN A.DATA_TYPE = 'NUMBER'
              AND A.DATA_SCALE <> 0
           THEN '(' || A.DATA_PRECISION || ',' || A.DATA_SCALE
                || ')'
         END
        )             DATA_LENGTH,
        A.COLUMN_ID
      FROM USER_TAB_COLUMNS A
        , USER_TAB_COMMENTS B
        , USER_COL_COMMENTS C
      WHERE (A.TABLE_NAME = B.TABLE_NAME)
            AND (A.TABLE_NAME = C.TABLE_NAME
                 AND A.COLUMN_NAME = C.COLUMN_NAME
            )) A1
  , (SELECT
       A.TABLE_NAME,
       A.COLUMN_NAME,
       B.CONSTRAINT_TYPE
     FROM USER_CONS_COLUMNS A
       , USER_CONSTRAINTS B
     WHERE (A.CONSTRAINT_NAME = B.CONSTRAINT_NAME)
           AND B.CONSTRAINT_TYPE IN ('P', 'R')) B1
WHERE (A1.TABLE_NAME = B1.TABLE_NAME (+)
       AND A1.COLUMN_NAME = B1.COLUMN_NAME (+))
ORDER BY A1.TABLE_NAME, A1.COLUMN_ID;