INSERT INTO <USER>.<ДРУГАЯТАБЛИЦА> ...

alter table OSTATOK_KRED add(...

SQL> create table emp_test
   2   (
   3    emp_id number constraint pk_emp_test primary key,
   4    emp_name varchar2( 30 )
   5   )
   6   ;

Table created.

SQL> create table orders_test
   2   (
   3    order_id number,
   4    emp_id number
   5   )
   6   ;

Table created.

SQL> 
SQL> alter table orders_test add constraint fk_orders_test foreign key(emp_id) references emp_test(emp_id);

Table altered.

SQL> create unique index u_orders_test on orders_test(emp_id);

Index created.

SQL> insert into emp_test values( 1 ,'First emp');

 1  row created.

SQL> select (select object_name from dba_objects where object_id= l.object_id) obj from v$locked_object l;

OBJ
---------------------------------------------------------------------------------------------------------------
ORDERS_TEST
EMP_TEST

SQL> alter table orders_test add (add_filed varchar2( 200 ));
alter table orders_test add (add_filed varchar2( 200 ))
*
ERROR at line  1 :
ORA- 00054 : resource busy and acquire with NOWAIT specified

CREATE TABLE t1( i iNT );
CREATE TABLE t2( j INT );

ALTER TABLE t2
    ADD CONSTRAINT pk_t1 PRIMARY KEY( j );
	
ALTER TABLE t1
    ADD CONSTRAINT ref_t1_t2 FOREIGN KEY (i) REFERENCES t2(j);
	 
INSERT INTO t2(j) VALUES( 1 );

ALTER TABLE t1
    ADD j2 INT;

ROLLBACK;

DROP TABLE t1;
DROP TABLE t2;

Table created.
Table created.
Table altered.
Table altered.
 1  row created.
Table altered.
Rollback complete.
Table dropped.
Table dropped.

SQL> CREATE TABLE t1( i iNT );

Table created.

SQL> CREATE TABLE t2( j INT );

Table created.

SQL> 
SQL> ALTER TABLE t2
   2       ADD CONSTRAINT pk_t1 PRIMARY KEY( j );

Table altered.

SQL>  
SQL> ALTER TABLE t1
   2       ADD CONSTRAINT ref_t1_t2 FOREIGN KEY (i) REFERENCES t2(j);

Table altered.

SQL>   
SQL> INSERT INTO t2(j) VALUES( 1 );

 1  row created.

SQL> ALTER TABLE t1
   2       ADD j2 INT;
ALTER TABLE t1
*
ERROR at line  1 :
ORA- 00054 : resource busy and acquire with NOWAIT specified