1 00:00:00,180 --> 00:00:07,290 In this video, we are going to develop dynamic DB query and scan operations for our product Lambda 2 00:00:07,290 --> 00:00:10,920 Microservices using Dynamic DB Client SDK package. 3 00:00:11,370 --> 00:00:16,500 Before we start, it is good to remember you can create operations on Dynamic DB. 4 00:00:16,710 --> 00:00:19,470 To do so, please check the documentation. 5 00:00:19,470 --> 00:00:21,840 See that scan operation in Amazon? 6 00:00:21,840 --> 00:00:28,750 Dynamic DB reads every item in a table, so that means it is very costly and we should await these dynamic 7 00:00:28,750 --> 00:00:31,300 DB scan operations as soon as possible. 8 00:00:31,320 --> 00:00:38,010 And here you can see the an example CLI command that we can also provide these slide command operations. 9 00:00:38,010 --> 00:00:40,320 So you can comment on dynamic DB. 10 00:00:40,350 --> 00:00:46,350 Here you can see the table name and we can also give additional feature expression over the table name. 11 00:00:46,350 --> 00:00:52,200 But nevertheless, you can command, always overview and read every item in the table. 12 00:00:52,200 --> 00:00:54,630 So that's why it is a bit dangerous. 13 00:00:54,630 --> 00:00:59,160 And we have also created a command to perform query operations Dynamo DB. 14 00:00:59,190 --> 00:01:01,920 It is the best practice to use query command. 15 00:01:01,950 --> 00:01:05,400 Here you can see the Dynamo DB Query Select Command. 16 00:01:05,430 --> 00:01:12,270 Again, we also provide a table name, but this time we can provide key condition, expression and expression 17 00:01:12,270 --> 00:01:14,940 attribute values for the other attributes. 18 00:01:15,240 --> 00:01:23,190 OC After understand the basics, we can go back to our code and we can see how we can implement these 19 00:01:23,190 --> 00:01:24,480 query operation. 20 00:01:24,660 --> 00:01:29,650 As you remember that we have already implemented scan operation into the get all products. 21 00:01:29,670 --> 00:01:36,510 If you go to this method, see that we perform scan command with placing these parameters, the only 22 00:01:36,510 --> 00:01:37,710 parameter is a table name. 23 00:01:37,710 --> 00:01:43,140 So that means it is reading all items in the table name and it is a bit costly. 24 00:01:43,290 --> 00:01:50,940 So if you go back to our main function and the function, so here you can see the HTTP get operations 25 00:01:50,940 --> 00:01:56,190 accommodate in this line of code we basically perform check the parameters. 26 00:01:56,190 --> 00:01:59,700 If there is a parameters, we are using the get item command. 27 00:01:59,730 --> 00:02:06,180 If there is no parameters, we are getting all products on the DB table with using scan command. 28 00:02:06,310 --> 00:02:10,530 Now I'm going to add a new HTTP get request. 29 00:02:10,560 --> 00:02:18,670 Let me show in here so you can see the expected HTTP, get request to our product Lambda Microservice 30 00:02:18,720 --> 00:02:19,440 function. 31 00:02:19,530 --> 00:02:23,820 So now this code is accommodate these two requests. 32 00:02:23,820 --> 00:02:29,820 The first one is the parameters we checking the ID information gate product by ID and the second one 33 00:02:29,820 --> 00:02:33,150 is the gate all products with performing the scan command. 34 00:02:33,150 --> 00:02:41,490 So now I'm going to expect any HTP gate method with providing both parameters and also query setting 35 00:02:41,490 --> 00:02:42,450 parameters. 36 00:02:42,450 --> 00:02:50,130 So how we can accommodate this request in this line of code, of course, we should write any if statement 37 00:02:50,130 --> 00:02:51,540 into the gate. 38 00:02:51,540 --> 00:02:58,620 BLOCK So for that purpose, I'm going to write an E flow and after that I can change the below if log 39 00:02:58,620 --> 00:02:59,410 is LC. 40 00:03:00,840 --> 00:03:03,680 Here you can see the our development codes. 41 00:03:03,690 --> 00:03:09,480 Basically, we have checking to create setting parameters and if there is a query setting parameters 42 00:03:09,480 --> 00:03:12,760 so that means it should be get products by category. 43 00:03:12,780 --> 00:03:17,180 With passing event, we are performing to get products by category. 44 00:03:17,190 --> 00:03:20,610 And in this method we will perform query command operations. 45 00:03:20,610 --> 00:03:29,580 So as you can see that we basically accommodate all these requests from more specific one to less specific 46 00:03:29,580 --> 00:03:30,060 one. 47 00:03:30,060 --> 00:03:35,970 So the code structure looking for the query setting parameter if there is a query in parameter, so 48 00:03:35,970 --> 00:03:38,370 that means get product by category. 49 00:03:38,430 --> 00:03:45,420 If there is no category in the query setting parameter, we are checking the parameters and that means 50 00:03:45,420 --> 00:03:49,230 it is a get product by ID if there is no parameters. 51 00:03:49,230 --> 00:03:54,570 So in that case, this is to get all products and to perform second command. 52 00:03:54,570 --> 00:04:00,330 So let's focus on this line of code and how we can implement these methods before we start. 53 00:04:00,330 --> 00:04:02,610 It is good to check the documentation. 54 00:04:02,610 --> 00:04:09,030 Please open the dynamic DB SDK documentation and open the query command and see that how we can perform 55 00:04:09,030 --> 00:04:10,830 query command and see the example. 56 00:04:10,830 --> 00:04:12,000 Use it in here. 57 00:04:12,000 --> 00:04:18,450 And if you go to query command input object, we will see the parameters that we can define when performing 58 00:04:18,460 --> 00:04:20,700 to query command on dynamic DB tables. 59 00:04:21,030 --> 00:04:24,000 Okay, let's go back to our we to do code. 60 00:04:24,000 --> 00:04:29,190 And if you go to get all products, you can see the second command example in here. 61 00:04:29,220 --> 00:04:36,030 After the these get all products, I'm going to develop a method which name is get products by category. 62 00:04:36,150 --> 00:04:44,400 If you can see in here, we basically will get products by category with this this line of codes. 63 00:04:44,400 --> 00:04:48,030 So first of all, I'm going to import record statements. 64 00:04:48,030 --> 00:04:51,870 Let me see what we are going to import. 65 00:04:51,870 --> 00:04:59,640 So the DB client and new query command, see that query command should be import or dynamic DB client 66 00:04:59,640 --> 00:05:00,660 SDK package. 67 00:05:00,690 --> 00:05:04,230 Go on top of the page and come here after the update command. 68 00:05:04,230 --> 00:05:10,080 I'm going to put comma and write query command into the client dynamic DB SDK package. 69 00:05:10,110 --> 00:05:17,160 If you go back to our main method, which is get product by category, you can come here and see that 70 00:05:17,160 --> 00:05:21,540 this time we can use Query Command OC before we start explaining. 71 00:05:21,540 --> 00:05:28,890 We should understand which HTTP method and which URL will be accommodated in this line of methods. 72 00:05:28,890 --> 00:05:31,920 So basically we will accommodate this request. 73 00:05:31,920 --> 00:05:38,280 So that means we will start with logging and after the track block, the first thing we should do is 74 00:05:38,310 --> 00:05:44,790 getting product ID and category information from the pet parameters and the query setting parameters. 75 00:05:44,790 --> 00:05:45,930 This is important. 76 00:05:45,930 --> 00:05:50,310 For example, we are getting queries, setting parameters category, so that means it is return back 77 00:05:50,310 --> 00:05:52,560 to form in the category variable. 78 00:05:52,560 --> 00:05:58,470 And after that we get the pet parameters ID information into the product ID variable. 79 00:05:58,560 --> 00:06:04,860 After getting these two variables, we can prepare the parameters of the query command and in the parameters 80 00:06:04,860 --> 00:06:10,260 we provide the key condition, expression, filter, expression and expression, attribute, values 81 00:06:10,260 --> 00:06:11,220 and the table name. 82 00:06:11,220 --> 00:06:19,050 So these is the query command parameters that we are defining the product ID and also category information 83 00:06:19,050 --> 00:06:23,340 to query our table looking for the category information. 84 00:06:23,370 --> 00:06:30,120 After that, we will send a dynamic client object to create a command and get back to await response 85 00:06:30,120 --> 00:06:35,520 into the item result to get these all items and return back to items into our function. 86 00:06:35,520 --> 00:06:40,530 So this is the get products by category method that we will implement this file. 87 00:06:40,560 --> 00:06:42,870 Please save the index case file. 88 00:06:42,930 --> 00:06:50,760 And as you can see that we have successfully developed the whole product microservices for performing 89 00:06:50,760 --> 00:06:56,490 CRUD operation over the dynamic DB table and response back to API gateway to the client application.