一、如何进入sqlite3交互模式进行命令操作？

1、确认sqlite3是否已经安装

进去python命令行，执行

>>> import sqlite3
>>>

没有报错，说明sqlite3已经成功安装了

2、如何进入sqlite3命令行

sqlite3 /path/to/dbname

直接执行sqlite3 加数据库名即可

 ~ sqlite3 ~/Downloads/django_test/cmdb/db.sqlite3 
sqlite3SQLite version 3.14.0 2016-07-26 15:17:14
Enter ".help" for usage hints.
sqlite>

3、.tables ：查看所有表

sqlite> .tables
auth_group                  django_content_type       
auth_group_permissions      django_migrations         
auth_permission             django_session            
auth_user                   ucloud_project            
auth_user_groups            ucloud_region             
auth_user_user_permissions  ucloud_uhost              
django_admin_log            ucloud_zone

4、查询表中总的数据条目数

select count() from TableName;

例如：

sqlite> select count() from ucloud_zone;
11
sqlite> select count() from ucloud_uhost;
147
sqlite> select count() from ucloud_project;
10

5、执行多条查询语句

sqlite> select
   ...> (select count(1) from ucloud_uhost) as uhost,
   ...> (select count(1) from ucloud_project) as project,
   ...> (select count(1) from ucloud_region) as region
   ...> ;
147|10|8

6、格式化输出

您可以使用下列的点命令来格式化输出为本教程下面所列出的格式：

sqlite>.header on
sqlite>.mode column
sqlite>.timer on
sqlite>

更多命令查看：

http://www.runoob.com/sqlite/sqlite-commands.html

二、python如何执行sqlite查询命令

python执行sqlite命令的流程：

1、cx = sqlite3.connect("db.sqlite3)

创建或打开数据库文件，如果数据库文件不存在，则创建，存在，则打开该文件。cx为数据库连接对象，它可以有以下操作： commit()–事务提交 rollback()–事务回滚 close()–关闭一个数据库连接 cursor()–创建一个游标

2、cursor = cx.cursor()

定义了一个游标。游标对象有以下的操作： execute()–执行sql语句 executemany–执行多条sql语句 close()–关闭游标 fetchone()–从结果中取一条记录 fetchmany()–从结果中取多条记录 fetchall()–从结果中取出多条记录 scroll()–游标滚动 关于对象的方法可以去 Python 主页上查看DB API的详细文档

3、 cursor.execute("""
... select
... (select count(1) from ucloud_uhost) as uhost
... """)

cursor.execute(sql语句)是执行sql语句

4、cursor.close()

关闭游标

下面是操作数据库的过程

>>> import sqlite3
>>> from django.db import connections
cx = sqlite3.connect("/Users/cengchengpeng/Downloads/django_test/cmdb/db.sqlite3")
cursor = cx.cursor()
>>> cursor
<sqlite3.Cursor object at 0x10b24cb20>
>>> cursor.execute("""
... select
... (select count(1) from ucloud_uhost) as uhost,
... (select count(1) from ucloud_project) as project,
... (select count(1) from ucloud_zone) as zone
... """)
<sqlite3.Cursor object at 0x10b24cb20>
>>> cursor.description
(('uhost', None, None, None, None, None, None), ('project', None, None, None, None, None, None), ('zone', None, None, None, None, None, None))
>>> columns = [_[0].lower() for _ in cursor.description]
>>> columns
['uhost', 'project', 'zone']
>>> for _ in cursor:
...     print _
... 
(147, 10, 11)
>>> results = [dict(zip(columns, _)) for _ in cursor]
>>> results
>>> results
[{'project': 10, 'zone': 11, 'uhost': 147}]
>>> cursor.close()

写python脚本，来执行sqlite语句

#coding:utf-8
from django.db import connections

def open_sql_dict(sql, connection_name='default'):
    dbs = connections[connection_name]
    cursor = dbs.cursor()
    cursor.execute(sql)
    columns = [_[0].lower() for _ in cursor.description]
    results = [dict(zip(columns, _)) for _ in cursor]
    cursor.close()
    return results

这里脚本里面，用到了zip()方法和dict()方法