Data definition language
- 简写 DDL
- 数据定义语言
CREATE TABLE
- 新建表
CREATE TABLE STUDENT(
S_ID NUMBER(10),
S_NAME VARCHAR2(20),
ST_SEX VARCHAR2(3),
ST_JOIN_DATE DATE
);
ALTER TABLE
- 修改表
ADD
- 增加列
ALTER TABLE STUDENT ADD(AGE NUMBER(3));DROP COLUMN
- 删除列
ALTER TABLE STUDENT DROP COLUMN AGE;RENAME COLUMN ... TO ...
- 修改字段名
ALTER TABLE STUDENT RENAME COLUMN ST_TD TO ST_ID;MODIFY
- 修改字段属性
ALTER TABLE STUDENT MODIFY ST_HOBBY VARCHAR2(50);
RENAME ... TO ...
- 修改表名
RENAME STUDENT TO STUDENTS;
DROP TABLE
- 删除表
DROP TABLE STUDENTS;
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