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- [Instructor] Hi and
welcome back to the course.

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In this video, we're going
to do the last method

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of our item resource,

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and then in the next
one, we do the item list.

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The last method is put and
that has to insert an item

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or update an item.

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So the first thing we have to do is,

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just as we've done here,

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find if the item already
exists or not, okay?

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So let's do that.

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Let's say that the item
is not the next item

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available in this filter,

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which is what we used to be.

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Now this is self.find_by_name,

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as we have used in the past.

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I'm also going to move the
item outside this item here

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and put it over there

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and you'll see why in just a moment.

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This item is a dictionary representing

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sort of the updated item,

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the item with a new price.

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Obviously it cannot have the same name,

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so I'm gonna call it updated_item instead.

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If it had the same name,

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it would just override the previous one

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and then that wouldn't make a lot of sense

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when it comes to checking if it is none.

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It wouldn't be none if it's a dictionary.

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Okay so if the item is none,

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meaning it wasn't found on the database,

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then what we're going to do,

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is we're going to say
self.insert the item.

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Sorry, the updated_item,
not the item itself.

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And if the item was not none,

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it means that it exists already.

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What we're gonna do is self.update,

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the updated_item.

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Okay, of course this
self.update doesn't exist,

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so we're also going to
have to create that one,

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which is another classmethod,

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called update(cls, item).

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Let's have a wee look
at how that may be done.

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Updating in SEQUEL is
going to be very similar

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to our other methods,

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so I'm just gonna copy this
there so I don't bore you.

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And all we're doing, once again,

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is setting up a connection,
creating a cursor,

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creating a query, and
then running the query

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using the cursor,

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and finally committing the connection

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to save things to disc and
closing that connection.

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Okay?

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Now the query is no longer
going to be delete from items.

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It is going to be update items.

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Now we're gonna update the items table,

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but we don't want to
update the entire table.

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We have to set a column.

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We're going to set the
price column to be equal to

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one of these parameters.

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And remember, this is going
to update the items table.

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So it's gonna set every price in the table

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to be this parameter,

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unless we have a name equals something.

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So now it's only gonna update the one

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where the name is equal
to the question mark.

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Then we're gonna execute the query,

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but it's gonna have two
parameters, the price and the name.

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And they have to be in
order, remember that.

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So item price goes first.

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And item name goes after.

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Remember this method is
receiving an item parameter,

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which is a dictionary of name and price.

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Okay.

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So now we've got the insertion
or the updates of the item.

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And all that's left is making sure

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that we are dealing with any
potential unexpected issues

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so we're gonna surround these

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with try except blocks.

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Now we're gonna return a message saying

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an error occurred inserting the item.

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And we're gonna do the same for this.

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But instead of inserting,
it's gonna be update.

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Remember to return the error 500.

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That's very important.

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And at the end, don't return item

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because that's the item
we found originally.

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What we want to return is
the updated_item, okay?

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And that's it, really.

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The put method, as you
can see, is fairly simple.

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All we are doing is finding
the item in the database

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and, if it exists, we're updating it,

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and if it doesn't, we're inserting it.

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And because we've extracted
the code to do these things

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outside of any specific method,

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it means it can be re-used.

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And that's a really useful thing.

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That's everything in this video.

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We now can update our items.

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You can go ahead in
Postman and try it out,

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but believe me, it does work.

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It does do what you'd expect.

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In the next video, we're
going to go over the item list

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and how we can retrieve all
our items from the database

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and there we're gonna
perform some final checks

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in Postman as well.

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I'll see you in the next video.