not permanent insert into stud values('myname')

Hello ,

following is a part of my code , can any body tell me why it works fine ,
but 'myname' does not remain permanent in the table although I'm loging in as postgres
and see 'myname' in the result when I run the program ?

thanks ,
Rony .

--------------------- C code -------------------
res = PQexec(conn,"insert into stud values('myname')");
PQclear(res);
res = PQexec(conn,"select * from stud");
 
for (i=0;i<PQntuples(res);i++) {
  printf("\n answer is %s",PQgetvalue(res,i,0));

---------------------- output -----------------------
#a.out
answer is rony
answer is myname
#
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