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Now we're almost done with the module,

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we learned a lot about querying operators and also about cursors,

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now let's talk about how we can shape the data which we do get back into the form we needed in. Because

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in the example of our movies, we have all that data for every document we return, that might simply be too

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much data,

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not only is it a lot of redundant data that we transfer over the wire

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if we don't need it, it also makes it harder for it to work with the data

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if we have to manually parse all that. Now with projection, we can control which data is returned.

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Let's say we are only interested in the name, the genres, the runtime and the rating and all the rest does

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not matter to us. If that is the case, I can write a query here without any criteria,

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let's say we fetch all documents in a pretty way

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but now I actually need to pass a second argument to find.

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Now for that, I also need to pass a first one and if I don't want to specify any criteria, any filter,

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I just add empty curly braces like this.

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The second argument to find then allows us to configure how values are projected,

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so how we actually extract the data fields

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and here we have a very simple syntax. If we want to get the name and the genres and the runtime and the

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rating,

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then we simply add name and add a one, that means the name field is something I want to include, the genres,

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that's also something I want to include as is the runtime,

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now last but not least, I also want to include the rating.

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Now all fields that I don't mention here with a one or that I explicitly add with a zero, like let's

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say image are not included but I don't need to add image zero here,

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it will be excluded by default.

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So if I hit enter, now I get a reduced version,

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you'll see that the ID is always included though and that is one exception, the ID is always included

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even if you don't specify it with a one. If you want to exclude the ID, that is possible but you have

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to explicitly set _ID to zero,

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that is not required for any other field but for the ID, it is

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and now we have our data without the ID.

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So now we return just the fields for every document that we are interested in

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which is of course very very helpful.

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You can also project on embedded documents, like for rating, you could say for the rating,

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I'm only interested in the average field and then you would simply use the path notation, rating.average

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and set this to one,

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however this will result in the same result because rating was an embedded document with only the average.

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So we can use a different example of course, in our data structure

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if I go up a bit, we see that we also have the schedule and let's say we're only interested in the time.

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Well schedule is an embedded document so we can just get the time

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by adding schedule.time and set this to one

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and now we will notice, the time is included but schedule also had an array of the days and that is

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now not included,

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so projection can also be used on embedded documents.

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Now projection can also work with arrays and help us a bit with array data that we include,

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now let me show you how that works.