數據庫的增刪改查和使用流程

創建表                      列名 類型,

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

2…create table  if not exists Student  (id integer , name text default '張三' , sex text not null, age  integer)

刪除表       表名

drop table Student

插入

全部列插入       表名              值               

insert into Student values (1, ‘張三’, ’男’, 18)

部分列插入

insert into Student (name, sex) values ( 'lisi', 'nv')

主鍵 (唯一, 不能重複)

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

查詢

所有數據

select * from Student

查詢姓名這一列 / 兩列

select name from Student

select name, sex from Student

條件查詢

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

只要前 5 條

select * from Student order by id asc limit 5

修改

1列

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

多列(勿忘逗號分隔)

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

刪除

數據

delete from Student where sex = ‘男'

全部

delete from Student

使用sqlite

1.打開數據庫

2.執行sql,做出數據處理

3.關閉數據庫

操作

1.打開數據庫

2.創建一個數據操作指針 stmt

3.執行sql 語句

4.處理結果