Question: I am trying to combine 3 different lists into 1 list. I was able to do it with 2 lists, but when I added a third I started getting an error saying 

```
ValueError: attempt to assign sequence of size 22 to extended slice of size 17.  

```

Each of the different lists should alternate. If there are no more items in the list to include in 'result', it should just alternate to other 2 lists. Any advice on how to enable this?

```
    print len(reddit_feed_dic)      #22
    print len(favorites_feed_dic)   #22
    print len(user_videos)          #6

    result = [None]*(len(favorites_feed_dic)+len(reddit_feed_dic)+len(user_videos))
    print len(result)
    result[::3] = reddit_feed_dic
    result[1::3] = favorites_feed_dic
    result[2::3] = user_videos

```

Here's an example with sample data:

```
reddit_feed_dic = [r1,r2,r3, ...r22]
favorite_feed_dic = [f1,f1,f3, ...f22]
user_videos = [u1, u2 u3, ...u6]

```

I would like result to be:

```
result = [r1,f1,u1, 
            r2, f2, u2,
            r3, f3, u3,
            r4, f4, u4,
            r5, f5, u5,
            r6, f6, u6,
            r7,f7,
            r8,f8,
            r9,f9,...

            r22,f22]

```

Answer: 
To get EF to create a table you need a `DbSet<T>` in your `DbContext`, assuming you have this it will create the table. 

The one caviat to this is that if you have a foreign key to something that isn't in you context EF will also assume its part of the database and create it. I think this is the behavior you are seeing.
EF should does not have any restrictions for "standalone" tables.

When you build EF tables once, additional changes will have to be followed by

* update of Context class (subclass of `DbContext`)
* adding migration script (generates API calls which will update database with new tables etc.)
* update database (run migration script).

You can find really good tutorial [here](http://msdn.microsoft.com/en-us/data/jj193542).