sqlite3常用命令以及django如
- 2020 年 1 月 9 日
- 筆記
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
