Оператор ALTER TABLE в ORACLE

alter table t1 add newcol varchar2(#cc66cc;">100);
 

alter table t1 add ( 
newcol_1 varchar2(#cc66cc;">100),
newcol_2 varchar2(#cc66cc;">100)
);
 

ALTER TABLE t1  MODIFY newcol varchar2(#cc66cc;">150);
 

alter table t1 MODIFY ( 
newcol_1 varchar2(#cc66cc;">150),
newcol_2 varchar2(#cc66cc;">150)
);
 

alter table t1 drop column newcol;
 

alter table t1 rename column oldcol to newcol;
 

alter table t1 rename to t2;
 

alter table t1 DISABLE constraint constraint_name;
 

ALTER TABLE table_name DROP CONSTRAINT constraint_name;
 

ALTER TABLE table_name ADD CONSTRAINT constraint_name UNIQUE (col_name);