Oracle 21c

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create table customer (custnum int primary key)
create table widget (stocknum int primary key)
create table purchased (
    custnum int,
    stocknum int, 
    pdate date,
    primary key (custnum, stocknum, pdate),
    foreign key (custnum) references customer,
    foreign key (stocknum) references widget
); 
select constraint_name
from user_cons_columns
where table_name = 'PURCHASED'
and column_name = 'CUSTNUM';


CONSTRAINT_NAME


SYS_C00113067

SYS_C00113068


select uc.constraint_name
from user_constraints uc
join user_cons_columns ucc on ucc.constraint_name = uc.constraint_name
where uc.table_name = 'PURCHASED'
and uc.constraint_type = 'R'
and ucc.column_name = 'CUSTNUM';


CONSTRAINT_NAME


SYS_C00113068


select ucr.constraint_name
from user_constraints ucp
join user_constraints ucr on ucr.r_constraint_name = ucp.constraint_name
where ucp.table_name = 'CUSTOMER'
and ucp.constraint_type = 'P'
and ucr.table_name = 'PURCHASED'
and ucr.constraint_type = 'R';


CONSTRAINT_NAME


SYS_C00113068