1.add ALTER TABLE table_name ADD( column datatype [DEFAULT EXPR][,column datatype…]);
- A. x, `1 K3 C8 l8 ]; B9 K n SQL>ALTER TABLE test ADD id NUMBER;
+ B& C% C/ _* s& o/ o) J' A7 D- i 2.modify
5 Z( H! Z ]; @1 y SQL>ALTER TABLE test MODIFY id VARCHAR2(15);
6 i0 |: ~# x6 P$ B W H7 y% V 3.delete3 g7 x5 i, V; e
SQL> ALTER TABLE test DROP COLUMN id;
; H' _4 S' E. W7 |+ {! h; C4 k 4.rename col
) Q: s' X" V3 n# I) c4 p. O( ] SQL>ALTER TABLE test RENAME COLUMN id TO nid;. A/ z3 H1 W" ?: L' p F' }% t
5.rename table
) K9 o0 ]. S& d# g3 L( e1 B SQL>RENAME test TO test1;2 T- n1 N8 k2 T% \
6.add comment, F% y4 K. B9 r v7 _( n
SQL>COMMENT ON TABLE test IS 'for test';5 U* P5 Z' S0 J6 i- N
SQL>COMMENT ON TABLE test.id IS 'id number' |