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Our steps have a description but don't actually have any content. Let's fix that!
blank=True - A field can be blank (not filled in) in the admin and any other forms based on the model.
default='something' - If no value is supplied for the field, the default 'something' will be put into the record.
If you said migrate when I asked what
else we have to do, you're right.
0:00
Good job remembering that dance.
0:04
You really do get used to
the steps pretty quickly.
0:05
Okay, let's see about adding that field.
0:08
Since we have some existing
rows in the database,
0:10
we're going to have to do something extra.
0:12
You know what, let's just do it.
0:13
Let's open up our models.py.
0:18
Let's add another text
field to the step model.
0:21
So, it doesn't matter where we put this.
0:23
It's not going to care.
0:26
So we're going to put it in here,
and this will be models.textfield.
0:29
Now we want to be sure and
0:33
call it content, because that's the name
we've been using in our template.
0:35
Yeah we can change it here and
0:39
change the template, but
who's gonna remember to do all that?
0:40
So, since we changed the data model,
we've changed the database.
0:43
Right?
Or, we want to.
0:49
Then, we should also change
the database with a migration.
0:51
So, we're gonna CONTROL- C to quit.
0:58
And, if you remember how to do this,
you're gonna makemigrations for courses.
1:03
And, we're gonna run this,
and we just got a message.
1:10
We haven't gotten this message before.
1:13
Let's read this and see what this says.
1:14
So we're trying to add a non-nullable
field content to step without a default.
1:16
Can't do that, the database needs
something to populate existing rows, so
1:23
please provide a fix.
1:26
I have to provide a one off default now,
1:27
which would be set on all
of the existing rows.
1:29
Or quit, and add a default in models.py.
1:31
The problem is that we've added
this field, our content field, and
1:35
it can't be null.
1:38
Since this is just listed as a text field,
there has to be something in that field.
1:39
Or Django has to know what to do with it,
if there's nothing in that field.
1:43
That would be fine if we didn't have
existing rows in the database, but we do.
1:47
We have some steps that
we've already made.
1:51
So, Django doesn't know what to do with
the rows that are already in the database.
1:54
Our database doesn't know what to
let Django do with the rows that
1:58
are already in the database.
2:00
So basically Django and
2:01
the database have thrown up their
hands,and going hey tell us what to do.
2:02
So we can either provide
an existing default for
2:07
all the ones that have
already been put in.
2:10
And that'll only happen now.
2:13
It won't happen when we run
it on another database.
2:14
Or, we can quit, and
we can set a default in the model.
2:17
And that will happen no matter what.
2:22
I think we should quit and
change the model.
2:25
So, I'll hit control two,
I guess I should hit two, but whatever.
2:27
Most of the time we would
let our field be nullable.
2:33
Which means that it can hold no data.
2:36
But since this is a text field,
that creates
2:38
a weird way of having two false values for
empty text, or character fields.
2:41
We don't want that.
2:46
We want one single obvious explicit
way of having a false value.
2:47
So, let's just set that.
2:52
What we're gonna do is we're gonna
come over here to our tex' field, and
2:54
we're gonna set, blank equals true.
2:57
And that controls the form in our admin.
2:59
So, it says, hey,
you don't have to get a value here.
3:03
And the default,
if they don't put anything in,
3:06
is going to be an empty string.
3:09
So the worst case scenario,
3:11
the nobody provided any data scenario,
is an empty string.
3:14
Which is fine,
an empty string is a little bit of data.
3:18
And it can be blank in the form,
we don't have to have value in the form.
3:20
Okay, so,
let's try making this migration again.
3:25
Cool, it made the migration.
3:31
And now we can go ahead and
migrate our model.
3:32
There we go.
Done and it's okay.
3:41
No problems.
3:43
So, let's go add some content
to our step in the admin.
3:44
So that means we need to run server again.
3:48
And let's see,
we're looking at using the shell.
3:52
So let's refresh this page.
3:56
Now we have a content field for
each of these.
3:59
So here's using the shell,
here's our content.
4:02
So let's add in a little
bit of stuff here.
4:04
So we'll say launch the shell with python.
4:07
You can exit the shell by entering exit or
Quit.
4:16
You can also exit the shell
by pressing Ctrl+D.
4:27
Okay.
4:33
So let's go save that.
4:34
And let's come over here and
refresh our page.
4:38
And here's each of our lines.
4:40
And, if we inspect one of these.
4:42
We see <p> tags around it.
4:48
So that's great,
we got paragraphs just like we wanted.
4:49
You might want to go back
through our other templates, and
4:53
put the line breaks filter into places
where we printed out the descriptions.
4:55
You know something we've been
missing through this entire course?
4:58
We don't have a single link anywhere.
5:01
We should use anchor tags.
5:03
They're a great part of HTML.
5:04
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