Question

Can i find out if a column is a primary or foreign key through Oracle’s ALL_TAB_COLS view?

select * 
from all_tab_cols 
where table_name = 'ALL_TAB_COLS'
;

1   SYS ALL_TAB_COLS    OWNER   VARCHAR2            30          N   1       <Long>                                  CHAR_CS 30  NO  NO      30  B   NO  YES NO  NO  1   1
2   SYS ALL_TAB_COLS    TABLE_NAME  VARCHAR2            30          N   2       <Long>                                  CHAR_CS 30  NO  NO      30  B   NO  YES NO  NO  2   2
3   SYS ALL_TAB_COLS    COLUMN_NAME VARCHAR2            30          N   3       <Long>                                  CHAR_CS 30  NO  NO      30  B   NO  YES NO  NO  3   3
4   SYS ALL_TAB_COLS    DATA_TYPE   VARCHAR2            106         Y   4       <Long>                                  CHAR_CS 106 NO  NO      106 B   NO  YES NO  NO  4   4
5   SYS ALL_TAB_COLS    DATA_TYPE_MOD   VARCHAR2            3           Y   5       <Long>                                  CHAR_CS 3   NO  NO      3   B   NO  YES NO  NO  5   5
6   SYS ALL_TAB_COLS    DATA_TYPE_OWNER VARCHAR2            30          Y   6       <Long>                                  CHAR_CS 30  NO  NO      30  B   NO  YES NO  NO  6   6
7   SYS ALL_TAB_COLS    DATA_LENGTH NUMBER          22          N   7       <Long>                                          NO  NO      0       NO  YES NO  NO  7   7
8   SYS ALL_TAB_COLS    DATA_PRECISION  NUMBER          22          Y   8       <Long>                                          NO  NO      0       NO  YES NO  NO  8   8
9   SYS ALL_TAB_COLS    DATA_SCALE  NUMBER          22          Y   9       <Long>                                          NO  NO      0       NO  YES NO  NO  9   9
10  SYS ALL_TAB_COLS    NULLABLE    VARCHAR2            1           Y   10      <Long>                                  CHAR_CS 1   NO  NO      1   B   NO  YES NO  NO  10  10
11  SYS ALL_TAB_COLS    COLUMN_ID   NUMBER          22          Y   11      <Long>                                          NO  NO      0       NO  YES NO  NO  11  11
12  SYS ALL_TAB_COLS    DEFAULT_LENGTH  NUMBER          22          Y   12      <Long>                                          NO  NO      0       NO  YES NO  NO  12  12
13  SYS ALL_TAB_COLS    DATA_DEFAULT    LONG            0           Y   13      <Long>                                  CHAR_CS 0   NO  NO      0       NO  YES NO  NO  13  13
14  SYS ALL_TAB_COLS    NUM_DISTINCT    NUMBER          22          Y   14      <Long>                                          NO  NO      0       NO  YES NO  NO  14  14
15  SYS ALL_TAB_COLS    LOW_VALUE   RAW         32          Y   15      <Long>                                          NO  NO      0       NO  YES NO  NO  15  15
16  SYS ALL_TAB_COLS    HIGH_VALUE  RAW         32          Y   16      <Long>                                          NO  NO      0       NO  YES NO  NO  16  16
17  SYS ALL_TAB_COLS    DENSITY NUMBER          22          Y   17      <Long>                                          NO  NO      0       NO  YES NO  NO  17  17
18  SYS ALL_TAB_COLS    NUM_NULLS   NUMBER          22          Y   18      <Long>                                          NO  NO      0       NO  YES NO  NO  18  18
19  SYS ALL_TAB_COLS    NUM_BUCKETS NUMBER          22          Y   19      <Long>                                          NO  NO      0       NO  YES NO  NO  19  19

Answer 1

No – you can’t since this information is not part of that view, see http://download.oracle.com/docs/cd/B13789_01/server.101/b10755/statviews_1179.htm

To find out the primary key column(s) of a table see http://www.techonthenet.com/oracle/questions/find_pkeys.php – the information is in the Views all_constraints + all_cons_columns .

To find foreign key information try:

SELECT cols.table_name, cols.column_name, cols.position, cons.status, cons.owner
FROM all_constraints cons, all_cons_columns cols
WHERE cons.constraint_type = 'R'
AND cons.constraint_name = cols.constraint_name
ORDER BY cols.table_name, cols.position;