1 00:00:02,100 --> 00:00:04,880 So now, with all of that out of the way, 2 00:00:04,880 --> 00:00:09,370 let's dive into the first important concept I wanna cover 3 00:00:09,370 --> 00:00:10,730 in this section. 4 00:00:10,730 --> 00:00:14,050 And that's the difference between real objects 5 00:00:14,050 --> 00:00:16,250 and data structures. 6 00:00:16,250 --> 00:00:20,810 Though I also wanna already make it clear that both terms, 7 00:00:20,810 --> 00:00:25,690 real objects and data structures, are made up terms. 8 00:00:25,690 --> 00:00:28,630 These are not official terms you will find anywhere, 9 00:00:28,630 --> 00:00:30,430 but this is simply a differentiation 10 00:00:30,430 --> 00:00:32,490 which you sometimes find out there, 11 00:00:32,490 --> 00:00:35,820 which can make sense when you're working with objects. 12 00:00:35,820 --> 00:00:38,170 So what is the difference between real objects 13 00:00:38,170 --> 00:00:41,320 and data structures or data containers, 14 00:00:41,320 --> 00:00:42,743 as we could also call it? 15 00:00:43,620 --> 00:00:48,610 A real object hides its internals, its properties, 16 00:00:48,610 --> 00:00:51,390 for example, by making them private, 17 00:00:51,390 --> 00:00:56,390 and it just exposes a public API, a couple of methods, 18 00:00:56,400 --> 00:01:00,330 which allow you to do various things with this object. 19 00:01:00,330 --> 00:01:02,020 And with these methods, 20 00:01:02,020 --> 00:01:04,510 I don't just mean getters and setters 21 00:01:04,510 --> 00:01:06,270 for these hidden properties. 22 00:01:06,270 --> 00:01:08,260 I mean real abstractions, 23 00:01:08,260 --> 00:01:11,160 so methods which do more complex things 24 00:01:11,160 --> 00:01:13,010 than just setting a property 25 00:01:13,010 --> 00:01:16,090 and therefore, acting as a proxy. 26 00:01:16,090 --> 00:01:18,620 Data containers or data structures, 27 00:01:18,620 --> 00:01:23,390 on the other hand, are simple objects where the properties 28 00:01:23,390 --> 00:01:26,420 and internals are made available publicly 29 00:01:26,420 --> 00:01:31,040 and where we have almost no public API besides that, 30 00:01:31,040 --> 00:01:32,963 almost no methods. 31 00:01:33,980 --> 00:01:36,670 Therefore real objects matter a lot 32 00:01:36,670 --> 00:01:40,020 if you're following an object-oriented programming style, 33 00:01:40,020 --> 00:01:41,300 And even if you don't, 34 00:01:41,300 --> 00:01:44,560 some real objects could be helpful for encapsulating 35 00:01:44,560 --> 00:01:46,420 and grouping logic together 36 00:01:46,420 --> 00:01:50,160 and today contain your core business logic, therefore. 37 00:01:50,160 --> 00:01:53,920 On the other hand, data containers are really just that. 38 00:01:53,920 --> 00:01:56,020 These are objects which are just used 39 00:01:56,020 --> 00:01:58,343 to store and transport data. 40 00:01:59,260 --> 00:02:02,600 For real objects, as I mentioned a couple of seconds ago, 41 00:02:02,600 --> 00:02:05,700 we prefer abstractions over concretions, 42 00:02:05,700 --> 00:02:08,200 which is a fancy term which simply means 43 00:02:08,200 --> 00:02:13,200 that we wanna expose methods which define a certain task 44 00:02:13,490 --> 00:02:15,790 that should be done, and then we don't care 45 00:02:15,790 --> 00:02:19,260 about how the object executes this task. 46 00:02:19,260 --> 00:02:22,640 Whereas, a data container doesn't really have any methods, 47 00:02:22,640 --> 00:02:25,330 and therefore, there we just have the concrete data, 48 00:02:25,330 --> 00:02:26,850 which is stored inside of it, 49 00:02:26,850 --> 00:02:29,850 and we can utilize that data in the places 50 00:02:29,850 --> 00:02:32,650 where we get access to the data container. 51 00:02:32,650 --> 00:02:35,370 So we don't tell the container to do something 52 00:02:35,370 --> 00:02:37,380 as we would to do it with a real object. 53 00:02:37,380 --> 00:02:40,870 We just can use it however we need to use it. 54 00:02:40,870 --> 00:02:44,350 And for example, here we have a database class 55 00:02:44,350 --> 00:02:47,240 which could be used to create real objects 56 00:02:47,240 --> 00:02:49,700 because it's hiding its internals 57 00:02:49,700 --> 00:02:52,090 and it then has a public API 58 00:02:52,090 --> 00:02:55,600 which abstracts away the internals. 59 00:02:55,600 --> 00:02:59,580 Connect and disconnect are pretty high level methods, 60 00:02:59,580 --> 00:03:03,610 which then internally do everything to set up a connection 61 00:03:03,610 --> 00:03:05,710 or to close a connection. 62 00:03:05,710 --> 00:03:09,420 And we don't know what exactly the class will do internally 63 00:03:09,420 --> 00:03:11,790 if we just call these methods. 64 00:03:11,790 --> 00:03:14,520 That is what abstraction means. 65 00:03:14,520 --> 00:03:18,690 We just connect to a database, which is an abstract concept, 66 00:03:18,690 --> 00:03:22,170 and how exactly that works is hidden away from us 67 00:03:22,170 --> 00:03:24,310 and is not our business 68 00:03:24,310 --> 00:03:27,343 if we are using such a database object. 69 00:03:28,200 --> 00:03:31,610 On the other hand, this user credentials clause here 70 00:03:31,610 --> 00:03:33,840 could be used to simply create 71 00:03:33,840 --> 00:03:36,640 a user credentials data container. 72 00:03:36,640 --> 00:03:38,610 All the data is exposed publicly. 73 00:03:38,610 --> 00:03:42,100 We have no methods, and we could just use objects 74 00:03:42,100 --> 00:03:46,400 based on this class to pass credentials around, for example, 75 00:03:46,400 --> 00:03:50,513 for example, as a parameter to a function or a method. 76 00:03:51,590 --> 00:03:54,460 And that's the difference between real objects 77 00:03:54,460 --> 00:03:55,970 and data containers. 78 00:03:55,970 --> 00:04:00,200 We can use classes for both to define these objects, 79 00:04:00,200 --> 00:04:03,600 but then how we use them differs. 80 00:04:03,600 --> 00:04:05,090 And now of course, the question 81 00:04:05,090 --> 00:04:07,490 is why does this matter at all? 82 00:04:07,490 --> 00:04:09,003 Why should you care?