1 00:00:07,730 --> 00:00:08,930 In this video. 2 00:00:08,930 --> 00:00:12,530 Let's talk about mongoose schema. 3 00:00:12,710 --> 00:00:16,040 What is it and why do we care about it? 4 00:00:16,700 --> 00:00:22,520 In short, schema simply means a way of creating document. 5 00:00:22,970 --> 00:00:27,290 So it's a blueprint of creating document. 6 00:00:27,380 --> 00:00:36,470 So looking at this picture here, you can see that we have the mother who is what, directing his or 7 00:00:36,470 --> 00:00:37,970 her children here. 8 00:00:38,510 --> 00:00:44,750 So the mother will decide that this is how I want my kids to behave. 9 00:00:45,260 --> 00:00:48,310 So it's a way of world creating documents. 10 00:00:48,320 --> 00:00:53,720 So these children are called the document when it comes to MongoDB. 11 00:00:53,870 --> 00:00:56,540 So let's see more about schema. 12 00:00:56,540 --> 00:00:57,220 In that way. 13 00:00:57,230 --> 00:00:59,750 You better understand what it is. 14 00:01:00,230 --> 00:01:10,640 The first point under schema is that it defines the structure of documents in a MongoDB collection. 15 00:01:11,300 --> 00:01:12,380 Dickey time. 16 00:01:12,380 --> 00:01:17,660 Here is what we call the structure of document. 17 00:01:17,780 --> 00:01:25,580 When we say structure of documents is simply means that the way you want your document or your record 18 00:01:25,580 --> 00:01:26,390 to be. 19 00:01:26,870 --> 00:01:35,450 So let's say that we are creating a block application and as a developer you are going to decide what 20 00:01:35,450 --> 00:01:40,010 kind of fields you want to be use in your blog application. 21 00:01:40,100 --> 00:01:47,300 So let's say for a blog, you want a user to provide a title of the blog, description of the blog, 22 00:01:47,300 --> 00:01:50,870 and provide image of the post or the blog. 23 00:01:50,900 --> 00:01:55,020 So this what you call this structure the way you want it. 24 00:01:55,040 --> 00:02:02,720 But when we are working with MongoDB alone, you could see that there is no structure here, there is 25 00:02:02,720 --> 00:02:03,740 no structure. 26 00:02:03,860 --> 00:02:12,170 Anybody can send any data into MongoDB as soon as the person provide the property here inside it is 27 00:02:12,170 --> 00:02:13,490 going to create. 28 00:02:13,820 --> 00:02:17,570 But with Mongoose you are going to have a way structured. 29 00:02:17,870 --> 00:02:24,710 So like I said, if you are using MongoDB like this one and you want to accept a specific field, unless 30 00:02:24,710 --> 00:02:29,030 we implement that validation, which is more work to do. 31 00:02:29,210 --> 00:02:38,120 So for MongoDB, like this one, I can go ahead and insert any property here or whatever and I can send 32 00:02:38,120 --> 00:02:39,940 any value into that when I save. 33 00:02:39,950 --> 00:02:45,950 It is going to create this field for me, even though as a developer I didn't state that. 34 00:02:45,950 --> 00:02:52,520 But as soon as a user provides, this is going to insert and we can avoid this one when you provide 35 00:02:52,520 --> 00:02:54,140 our custom validation. 36 00:02:54,260 --> 00:03:02,750 But with Mongoose, we have this structured we are going to decide that we want this field or this field 37 00:03:02,870 --> 00:03:07,060 in the field which is not specified inside our schema. 38 00:03:07,070 --> 00:03:09,990 We are going to throw an error to the user. 39 00:03:10,040 --> 00:03:12,530 That's how schema is. 40 00:03:12,530 --> 00:03:22,210 Or about the next point by schema is that we specify the data types for each field in a document. 41 00:03:22,220 --> 00:03:27,440 So this means that we can specify any kind of data type. 42 00:03:27,440 --> 00:03:35,030 For example, if you want to create a post, you have a title which is a string, let's say image a 43 00:03:35,030 --> 00:03:35,810 string. 44 00:03:35,840 --> 00:03:43,010 Let's see what's going to be array of tags and let's say a number of posts can be a number and we can 45 00:03:43,010 --> 00:03:45,620 achieve that using Mongoose. 46 00:03:45,620 --> 00:03:54,290 But with MongoDB, I can say that the field for a student here, let's say a mount, and when I enter 47 00:03:54,290 --> 00:04:01,970 it I can say true this a number, but when I create it I added a boolean value as a value which is not 48 00:04:01,970 --> 00:04:02,720 ideal. 49 00:04:02,750 --> 00:04:05,180 That is why Mongoose is awesome. 50 00:04:05,450 --> 00:04:13,040 The next point is that it validates the commands before they are inserted in a collection, as we discussed 51 00:04:13,040 --> 00:04:14,240 about Mongoose. 52 00:04:14,420 --> 00:04:19,040 The next point is that it specify default values for fields. 53 00:04:19,040 --> 00:04:26,930 So let's say that if you want to create a record, we can provide a default value, that if the user 54 00:04:26,930 --> 00:04:32,120 don't provide that value, you want to give a default value for a particular field. 55 00:04:32,450 --> 00:04:37,820 So let's say here we can provide a field says it's merit. 56 00:04:38,300 --> 00:04:43,100 So for this value, sometimes it's more private and most users don't want to provide. 57 00:04:43,100 --> 00:04:50,210 So by default we can say that by default, if a user don't provide, you will see false or true and 58 00:04:50,210 --> 00:04:54,170 we can achieve that inside mongoose code schema. 59 00:04:54,410 --> 00:05:00,470 And next is is specify other options such as whether a field is required. 60 00:05:00,470 --> 00:05:03,320 And that is what I said about validation. 61 00:05:03,440 --> 00:05:11,330 So let's say that we have this document that we want to inject into MongoDB and we have specified a 62 00:05:11,330 --> 00:05:14,240 structure that a name is required. 63 00:05:14,240 --> 00:05:21,290 But when a user is trying to insert, the user may forgot or not even to provide the value for this 64 00:05:21,290 --> 00:05:21,860 field. 65 00:05:21,860 --> 00:05:26,870 So if the user is trying to save it, the application is going to throw an error. 66 00:05:26,870 --> 00:05:30,100 In that way the document cannot be saved. 67 00:05:30,110 --> 00:05:31,460 That is awesome. 68 00:05:32,210 --> 00:05:37,700 So before we end up this video, let's talk about model. 69 00:05:37,730 --> 00:05:40,040 What is a model? 70 00:05:40,080 --> 00:05:45,560 Well, models are instance of a schema. 71 00:05:45,980 --> 00:05:53,510 So what comes back after we have created our schema is what we call the model. 72 00:05:53,690 --> 00:06:04,310 So we can say that the schema is a class of which we can create an instance of object out of the schema. 73 00:06:04,490 --> 00:06:09,230 So we call this one the first one as the schema. 74 00:06:09,740 --> 00:06:10,790 And then. 75 00:06:11,080 --> 00:06:14,860 Schema, we can create instances of the schema. 76 00:06:15,130 --> 00:06:21,160 So let's say that the name of a schema is person, schema person. 77 00:06:21,790 --> 00:06:25,730 So we can create many persons out from this schema. 78 00:06:25,750 --> 00:06:30,670 We can have person one, person two, and person three has that. 79 00:06:30,970 --> 00:06:34,550 So a model is an instance of a schema. 80 00:06:34,570 --> 00:06:37,150 So with that schema, there will be no model. 81 00:06:37,180 --> 00:06:41,890 So it's a model that is going to help us to interact with MongoDB. 82 00:06:42,070 --> 00:06:45,300 For example, you can have a model for users. 83 00:06:45,310 --> 00:06:52,000 So if we want to find all users, we are not going to interact with the schema, but instead we are 84 00:06:52,000 --> 00:06:54,130 going to interact with the model. 85 00:06:54,610 --> 00:06:57,400 This is what we call collection in MongoDB. 86 00:06:57,430 --> 00:06:57,910 Right. 87 00:06:57,910 --> 00:07:01,930 And on that we can have all the method like create on that. 88 00:07:02,140 --> 00:07:05,200 But with Mongoose, we call this one model. 89 00:07:05,350 --> 00:07:10,690 And on that, I'm going to have all the methods for Mongoose or MongoDB to interact. 90 00:07:10,720 --> 00:07:16,170 The cool part is that we can use Mongoose method like find delete. 91 00:07:16,180 --> 00:07:20,080 Likewise in the MongoDB method also. 92 00:07:20,110 --> 00:07:21,580 How awesome it is. 93 00:07:21,580 --> 00:07:26,440 That's why Mongoose extends the functionality of Mongo. 94 00:07:26,440 --> 00:07:33,490 DB Now that we have all the concepts done in this video, let's go ahead and create application and 95 00:07:33,490 --> 00:07:37,540 start working with Mongoose in the next video.