数据库的增删改查和使用流程

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创建表 列名 类型,

1…create table Student (id integer , name text, sex text, age integer)

2…create table if not exists Student (id integer , name text default ‘张三’ , sex text not null, age integer)

删除表 表名

drop table Student

插入

所有列插入 表名 值

insert into Student values (1, ‘张三’, ’男’, 18)

部分列插入

insert into Student (name, sex) values ( ‘lisi’, ‘nv’)

主键 (唯一, 不能反复)

create table Student (id integer primary key,name text, age integer, sex text )

查询

全部数据

select * from Student

查询姓名这一列 / 两列

select name from Student

select name, sex from Student

条件查询

select * from Student where age > 10

select * from Student where age > 10 and sex = ‘nv’

select * from Student where age between 15 and 20

升序/降序

select * from Student order by id sac / desc

仅仅要前 5 条

select * from Student order by id asc limit 5

改动

1列

update Student set age = 18 where sex = ‘男’

多列 (勿忘逗号分隔)

update Student set age = 16 , sex = ‘男’ where age < 19

删除

数据

delete from Student where sex = ‘男’

所有

delete from Student

使用sqlite

1.打开数据库

2.运行sql,做出数据处理

3.关闭数据库

操作

1.打开数据库

2.创建一个数据操作指针 stmt

3.运行sql 语句

4.处理结果

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