ORA-02270 solution

Preparation
SQL>
create table A (id number, soid number);

SQL>
create table B (id number);

Action
SQL> 
alter table A
add constraint SOID_B_FK
foreign key (soid)
references B (id);

Error
ORA-02270: no matching unique or primary key for this column-list

Reason
Parent table (B) does not have any primary key for matching with child table (A)

Solution
SQL>
alter table B
add constraint ID_PK 
primary key (id);

ORA-02266 solution

Action
A table has a PK (Primary Key)
B table has a FK (Foreign Key) and referenced to A table's PK

-> User tries to truncate table A

Error
ORA-02266: unique/primary keys in table referenced by enabled foreign keys

Solution I
Disable B table's FK
SQL> alter table HR.B disable constraint FK_B;
-- e.g. schema HR

Solution II
First truncate table B
SQL> truncate table B;

Then truncate table A
SQL> truncate table A;