CREATE TABLE memo(
 no NUMBER(5) NOT NULL
,from_id VARCHAR2(20)
,to_id VARCHAR2(20)
,memo_content VARCHAR2(4000)
,create_date DATE
,read_yn VARCHAR2(1)
);

CREATE UNIQUE INDEX SCOTT.PK_memo ON SCOTT.memo(no);

CREATE SEQUENCE seq_memo
START WITH 1
INCREMENT BY 1
MAXVALUE 99999
NOCYCLE
NOCACHE;