CREATE TABLE BOOKS

(

B_ID INT NOT NULL UNIQUE,

B_NAME VARCHAR2(20),

B_PUBLISH VARCHAR2(50),

B_PRICE NUMBER DEFAULT 0.00,

B_PUBDATE DATE DEFAULT SYSDATE

);

语法：

SELECT 列名1,列名2 FROM <table_name>;

SELECT * FROM BOOKINFO;

语法:

INSERT INTO BOOKS(B_ID,B_NAME,B_PUBLISH,B_PRICE,B_PUBDATE)

VALUES(1001,‘计算机文化基础‘,‘大众出版社‘,34.6,TO_DATE(‘2017.4.3‘,‘yyyy.mm.dd‘));

INSERT INTO BOOKS(B_ID,B_NAME,B_PUBLISH,B_PRICE,B_PUBDATE)

VALUES(1002,‘计算机硬件基础‘,‘科学出版社‘,44.6,TO_DATE(‘2017.4.3‘,‘yyyy.mm.dd‘));

数据中的NULL值处理：

INSERT INTO BOOKS(B_ID,B_NAME,B_PUBLISH,B_PRICE,B_PUBDATE)

VALUES(1003,‘数据库基础‘,‘北京大学出版社‘,NULL,NULL);

注意：插入NULL值得数据，前提是表中该字段允许为空值，即创建表示，没有NOT NULL约束；

创建表时，通过DEFAULT关键字指定列的默认值；

INSERT INTO BOOKS(B_ID,B_NAME,B_PUBLISH,B_PRICE,B_PUBDATE)

VALUES(1006,‘遥感信息处理‘,‘科学出版社‘,39.0,TO_DATE(‘2017.4.3‘,‘yyyy.mm.dd‘));

INSERT INTO BOOKS(B_ID,B_NAME,B_PUBLISH,B_PRICE,B_PUBDATE) VALUES(1007,‘图形图像处理‘,NULL,29.5,DEFAULT);

UNIQUE属性在当前表中的该列中的值必须是完全唯一的，并且只能出现一次；

用户需要根据已有表和视图的记录，将其中特定的数据添加到目标表中；

INSERT INTO BOOKS(B_ID,B_NAME,B_PUBLISH,B_PRICE,B_PUBDATE)

SELECT BOOKID,BOOKNAME,PUBLISH,PRICE,PUBDATE

FROM BOOKINFO;

语法：

UPDATE <table_or_view_name>

SET column_name = {expression | default | NULL}

WHERE <search_condition>

注意:一定不要忽略WHERE子句，如果没有指明WHERE子句，则数据库表中所有的行的记录都将被更新；

UPDATE BOOKS SET B_PUBLISH=‘邮电出版社‘ WHERE B_ID=1007;

语法：

DELETE FROM <table_or_view_name>

WHERE search_condition;

DELETE FROM BOOKS WHERE B_PUBLISH=’北京’;

删除BOOKS表中的所有记录；

TRUNCATE TABLE BOOKS;