django执行原始sql
一、执行raw()方法
Manager.raw(raw_query, params=None, translations=None)
这种方法通过执行原始的SQL查询并返回一个RawQuerySet实例。返回的RawQuerySet实例就如QuerySet一样能够迭代。
以使用raw()方法中的translations参数进行query 字段到model字段的映射。
>>> name_map = {'first': 'first_name', 'last': 'last_name', 'bd': 'birth_date', 'pk': 'id'}>>> table1.objects.raw('SELECT * FROM some_other_table', translations=name_map)
如果需要执行参数化查询,您可以使用params参数原始()
>>> name = 'Doe'>>> Person.objects.raw('SELECT * FROM myapp_person WHERE last_name = %s', [name])
直接执行自定义SQL
Manager.raw()远远不够，可直接执行自定义SQL，直接执行UPDATE, INSERT, DELETE，而这些都是manager.raw()不能实现的。所以要直接执行自定义SQL
操作流程如下：
导入 form django.db import connection,transaction
django.db.connection：代表默认的数据库连接
django.db.transaction：代表默认数据库事务（transaction）
connection.cursor()： 获得一个游标(cursor)对象
cursor.execute(sql, [params])：执行SQL
cursor.fetchone() 或者 cursor.fetchall()：返回结果行如果执行修改操作，则调用transaction.commit_unless_managed()来保证你的更改提交到数据库。
实例如下：
def sql(request): """
----------------------------------------------
Function: 执行原始的SQL
DateTime: 2013/x/xx
---------------------------------------------- """
from django.db import connection,transaction
cursor = connection.cursor() #获得一个游标(cursor)对象
#更新操作
cursor.execute('update other_other2 set name ="李四" where id=%s',[3]) #执行sql语句
transaction.commit_unless_managed() #提交到数据库
#查询操作
cursor.execute('select * from other_other2 where id>%s' ,[1])
raw = cursor.fetchone() #返回结果行 或使用 #raw = cursor.fetchall()
#如果连接多个数据库则使用django.db.connections
from django.db import connections
_cursor = connections['other_database'].cursor() #如果执行了更新、删除等操作
transaction.commit_unless_managed(using='other_databases')
return render_to_response('other/sql.html',{'raw':raw})
django.db.connections：针对使用多个数据库
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from
django.db
import
connections
cursor
=
connections[
'my_db_alias'
].cursor()
# Your code here...
transaction.commit_unless_managed(using
=
'my_db_alias'
)
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通常我们不需要手动调用transaction.commit_unless_managed(),我们可以这样做：
调用set_dirty()自动映射到操作的字段
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<span style
=
"color: #ff0000;"
>@commit_on_success<
/
span>
def
my_custom_sql_view(request, value):
from
django.db
import
connection, transaction
cursor
=
connection.cursor()
# Data modifying operation
cursor.execute(
"UPDATE bar SET foo = 1 WHERE baz = %s"
, [value])
# Since we modified data, mark the transaction as dirty
<span style
=
"color: #ff0000;"
>transaction.set_dirty()<
/
span>
# Data retrieval operation. This doesn't dirty the transaction,
# so no call to set_dirty() is required.
cursor.execute(
"SELECT foo FROM bar WHERE baz = %s"
, [value])
<span style
=
"color: #ff0000;"
> row
=
cursor.fetchone()<
/
span>
<span style
=
"color: #ff0000;"
>
return
render_to_response(
'template.html'
, {
'row'
: row})
<
/
span>
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五、个人常用：
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def
Message(request,msg_id):
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.........
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where
=
msg_id
sql
=
'''
select t.id, t.real_name, t2.* from auth_user t join (
select max(is_red) as is_red,add_user_id,task_id from card <br> where msg_id=%s GROUP BY task_id,add_user_id)
t2 ON t2.add_user_id=t.id
'''
%
where
cursor
=
connection.cursor()
cursor.execute(sql)
fetchall
=
cursor.fetchall()
card
=
[]
for
obj
in
fetchall:
dic
=
{}
dic[
'user_id'
]
=
obj[
0
]
dic[
'real_name'
]
=
obj[
1
]
dic[
'is_red'
]
=
obj[
2
]
dic[
'add_user'
]
=
obj[
3
]
dic[
'task_id'
]
=
obj[
4
]
card.append(dic)
context[
'card'
]
=
card
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六、整体实例演示
#搜索数据
if request.method == 'POST':
type = int(request.POST.get('type',0))
s_title = request.POST.get('s_title') if not type:
type = 'type>0'
else:
type = 'type=%s' %type
if s_title:
s_title = "title LIKE '%%%%%s%%%%'" %s_title else:
s_title = 'id>0'
sql = u'''
SELECT @row := @row + 1 as row,t.* FROM(SELECT * FROM version WHERE %s AND %s) t,(SELECT @row := 0) r ORDER BY release_date''' %(type,s_title) print sql
cursor = connection.cursor()
cursor.execute(sql)
fetchall = cursor.fetchall()
#添加、更新数据now = datetime.datetime.now() if request.method == 'POST':
id = int(request.POST.get('id',0)) #编辑对应id，如果新添加的则id=0
version = request.POST.get('no')
type = int(request.POST.get('type'))
title = request.POST.get('title')
content = request.POST.get('content')
if not id: #添加
sql = 'insert into version(type,version,title,content,release_date) values(%s,%s,%s,%s,%s)'
cursor = connection.cursor()
cursor.execute(sql,[type,version,title,content,now])
transaction.commit_unless_managed() return HttpResponse('ok') else: #编辑
sql = 'update version set type=%s,version=%s,title=%s,content=%s where id=%s'
cursor = connection.cursor()
cursor.execute(sql,[type,version,title,content,id])
transaction.commit_unless_managed() return HttpResponse('ok')
#异步获取数据... if request.method == 'POST':
id = int(request.POST.get('id',0))
cursor = connection.cursor()
cursor.execute('select * from version where id =%s',[id])
raw = cursor.fetchone()
lis =[]
dic = {}
dic['type'] =raw[1]
dic['version']=raw[2]
dic['title'] = raw[3]
dic['content'] = raw[4]
lis.append(dic) return ajax.ajax_ok(lis)
#删除数据
if request.method == 'POST':
id = int(request.POST.get('id',0))
cursor = connection.cursor()
cursor.execute('delete from version where id=%s',[id])
transaction.commit_unless_managed() return HttpResponse('ok')