DBA Tips Archive for Oracle


The BECOME USER System Privilege

by Jeff Hunter, Sr. Database Administrator

The "BECOME USER" System Privilege is one that has stirred up a lot of confusion amoung DBAs and developers. Oracle unfortunately does not support or comment on the use of this system privilege. I believe that import uses it to import objects in the schemas of other users.

Oracle has an undocumented OCI function called upicui that will allow a given oracle user to become another user. This user has to have the "BECOME USER" system privilege.

Provided below is a simple example using the "upicui" function:

** Test program to test the function "upicui".
#include <stdio.h>

#include <oratypes.h>
#include <ocidfn.h>
#include <ociapr.h>

Lda_Def  Lda;
ub1      Hda[256];

main() {
  int     ret;
  char    *user="TESTUSER";   /* The user name has to be in capital letters
                               ** or the same way it appears in sys.user$

  printf("Connecting to system/manager\n");
  ret = orlon( &Lda, Hda, (text *)"system/manager", -1, (text *)0, -1, 0 );
  if (ret) {
    fprintf(stderr, "Cannot connect ret=%d \n", ret );

  printf("Become user TESTUSER\n");
  ret = upicui( Hda, 0, user, strlen(user) );
  if (ret) {
    fprintf(stderr, "Cannot connect as %s. ret=%d \n", user, ret );
Compile / Link
# gcc -c -I$ORACLE_HOME/rdbms/public upicui.c
# gcc -L$ORACLE_HOME/lib/ -L$ORACLE_HOME/rdbms/lib/ -o upicui upicui.o -lclntsh
# ./upicui
Connecting to system/manager
Become user TESTUSER

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Last modified on
Tuesday, 03-Jan-2006 15:14:36 EST
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