How to make an external database query iterable?

问题:

I have the following code:

settings.py

DATABASES = {     'default': {         'ENGINE': 'django.db.backends.mysql',          'NAME': 'tectcom',                              'USER': 'test',                             'PASSWORD': '***146***',                          'HOST': '',                              'PORT': '',                           },      'cdr': {         'ENGINE': 'django.db.backends.mysql',         'NAME': 'ast',                              'USER': '123',                               'PASSWORD': '654',                          'HOST': '',                               'PORT': '',                          } 

views.py

def cdr_user(request):         cursor = connections['cdr'].cursor()         calls = cursor.execute('SELECT * FROM cdr')         return render_to_response("cdr_user.html",                 {'result':calls }, context_instance=RequestContext(request)) 

cdr_user.html

{% for res in result %}  {{ res.billsec }}<br />  {% endfor %} 

The table is like that:

+-------------+--------------+------+-----+---------------------+-------+ | Field       | Type         | Null | Key | Default             | Extra | +-------------+--------------+------+-----+---------------------+-------+ | calldate    | datetime     | NO   | MUL | 0000-00-00 00:00:00 |       |  | clid        | varchar(80)  | NO   |     |                     |       |  | src         | varchar(80)  | NO   |     |                     |       |  | dst         | varchar(80)  | NO   | MUL |                     |       |  | dcontext    | varchar(80)  | NO   |     |                     |       |  | channel     | varchar(80)  | NO   |     |                     |       |  | dstchannel  | varchar(80)  | NO   |     |                     |       |  | lastapp     | varchar(80)  | NO   |     |                     |       |  | lastdata    | varchar(80)  | NO   |     |                     |       |  | duration    | int(11)      | NO   |     | 0                   |       |  | billsec     | int(11)      | NO   |     | 0                   |       |  | disposition | varchar(45)  | NO   |     |                     |       |  | amaflags    | int(11)      | NO   |     | 0                   |       |  | accountcode | varchar(20)  | NO   | MUL |                     |       |  | userfield   | varchar(255) | NO   |     |                     |       |  | uniqueid    | varchar(32)  | NO   |     |                     |       |  | linkedid    | varchar(32)  | NO   |     |                     |       |  | sequence    | varchar(32)  | NO   |     |                     |       |  | peeraccount | varchar(32)  | NO   |     |                     |       |  +-------------+--------------+------+-----+---------------------+-------+ 

The problem is that I get a "Exception Value: 'long' object is not iterable"

How do I make result iterable to show it in my template? I've seen https://docs.djangoproject.com/en/dev/topics/db/sql/ and also other documentation, but I'm still lost in the code.

Thank you.

回答1:

To iterate over the result of a SQL query in Python, use cursor.fetchall() to turn it into a list of lists. There's a very handy recipe here for turning those results into an object you can easily access:

class SQLRow(object):     def __init__(self, cursor, row):         for (attr, val) in zip((d[0] for d in cursor.description), row) :             setattr(self, attr, val) 

Once you have that class, this is simple:

def cdr_user(request):     cursor = connections['cdr'].cursor()     calls = cursor.execute('SELECT * FROM cdr')     result = [SQLRow(cursor, r) for r in cursor.fetchall()]     return render_to_response("cdr_user.html",             {'result': result }, context_instance=RequestContext(request)) 

This way, the billsec attribute (and all other attributes) will still be accessible in your template.

回答2:

cursor.execute() doesn't return an iterable. It modifies the cursor object in place. Here's some documentation on this.

You need to call .fetchone() .fetchmany() or .fetchall() to retrieve the results, which should be iterables, e.g.:

def cdr_user(request):   cursor = connections['cdr'].cursor()   cursor.execute('SELECT * FROM cdr')   calls = cursor.fetchall()   return render_to_response("cdr_user.html",                             {'result':calls },                              context_instance=RequestContext(request)) 

文章来源: How to make an external database query iterable?