SQL query to find primary key

Question

Can anyone suggest a query that would return all of the columns in the primary key of a table? Information on why I'm asking can be found below.
I'm currently using the following query, but it won't work right if there are unique indexes on the table besides the primary key.
"select column_name from all_ind_columns c, all_indexes i where c.index_owner = i.owner and c.index_name = i.index_name and i.table_owner = {me} and i.table_name = {table_name} and uniqueness = 'UNIQUE'"
The reason I'm interested in the primary key is I need to merge the contents of table A into a table B with the same structure, and before I can do this I need to delete any rows that will cause insertion to fail.

Answer 1

In the column for constrain_type P is for primary key and R is for Foreign key
COLUMN TABLE_NAME NEW_VALUE TT_TAB NOPRINT
TTITLE 'TABLE: ' TT_TAB SKIP1
break on table_name skip page on constraint_name on constraint_type
COLUMN CONSTRAINT_NAME FORMAT A35
COLUMN COLUMN_NAME FORMAT A35
COLUMN REF_TAB_COL FORMAT A35
COLUMN POSITION NOPRINT
SELECT a.table_name, A.CONSTRAINT_NAME, B.COLUMN_NAME, B.POSITION,
       a.constraint_type, NULL REF_TAB_Col
FROM USER_CONSTRAINTS A, USER_CONS_COLUMNS B
WHERE A.CONSTRAINT_TYPE='P'
  AND A.CONSTRAINT_NAME = B.CONSTRAINT_NAME
UNION
select a.table_name, A.constraint_name, C.COLUMN_NAME, C.POSITION,
       a.constraint_type, B.TABLE_NAME||'.'|| B.COLUMN_NAME
from USER_constraints A, USER_IND_COLUMNS B, USER_CONS_COLUMNS C
where A.CONSTRAINT_TYPE = 'R'
  AND A.R_CONSTRAINT_NAME = B.INDEX_NAME
  AND A.CONSTRAINT_NAME = C.CONSTRAINT_NAME(+)
ORDER BY 1,2,4 ;