oracle 创建表时,表名称会自动转换成大写,oracle 对表名称的大小写不敏感。
oracle 表命名规则:
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-- 创建表: student_info 属主: scott (默认当前用户)
create table scott.student_info ( sno number(10) constraint pk_si_sno primary key, sname varchar2(10), sex varchar2(2), create_date date );
-- 添加注释 comment on table scott.student_info is '学生信息表'; comment on column scott.student_info.sno is '学号'; comment on column scott.student_info.sname is '姓名'; comment on column scott.student_info.sex is '性别'; comment on column scott.student_info.create_date is '创建日期';
-- 语句授权,如:给 hr 用户下列权限 grant select, insert, update, delete on scott.student_info to hr; |
插入验证数据:
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-- 插入数据 insert into scott.student_info (sno, sname, sex, create_date) values (1, '张三', '男', sysdate); insert into scott.student_info (sno, sname, sex, create_date) values (2, '李四', '女', sysdate); insert into scott.student_info (sno, sname, sex, create_date) values (3, '王五', '男', sysdate);
-- 修改 update scott.student_info si set si.sex = '女' where si.sno = 3;
-- 删除 delete scott.student_info si where si.sno = 1;
-- 提交 commit;
-- 查询 select * from scott.student_info; |
1. '增加' 一列或者多列
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alter table scott.student_info add address varchar2(50); alter table scott.student_info add (id_type varchar2(2), id_no varchar2(10)); |
2. '修改' 一列或者多列
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alter table scott.student_info modify address varchar2(100); alter table scott.student_info modify (id_type varchar(20), id_no varchar2(20)); |
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alter table scott.student_info rename column address to new_address; |
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alter table scott.student_info rename to new_student_info ; alter table scott.new_student_info rename to student_info; |
3. '删除' 一列或者多列,删除多列时,不需要关键字 column
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alter table scott.student_info drop column sex; alter table scott.student_info drop (id_type, id_no); |
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-- 删除表结构 drop table scott.student_info; |
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-- 清空表数据 truncate table scott.student_info; |
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'dba_xx' > all_xx > user_xx ('dba_xx' DBA 用户才有权限) |
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select * from dba_tables; -- all_tables、user_tables |
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select * from dba_tab_comments; |
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select * from dba_tab_cols t order by t.column_id; |
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select * from dba_col_comments; |