1 00:00:05,140 --> 00:00:05,500 All right. 2 00:00:05,500 --> 00:00:06,310 Welcome back. 3 00:00:06,310 --> 00:00:11,230 We're going to continue off right where we left off last time and first thing we need to do is make 4 00:00:11,230 --> 00:00:14,100 sure that we set our flask application variable correctly. 5 00:00:14,230 --> 00:00:22,600 Since I renamed my file to be models not pie I'm going to set a flask app equal to models of Pi and 6 00:00:22,600 --> 00:00:24,220 this is something you're always going to have to do. 7 00:00:24,220 --> 00:00:28,150 In case you play around the name of your actual application file. 8 00:00:28,150 --> 00:00:29,310 So I will set that. 9 00:00:29,320 --> 00:00:34,480 Remember if you're on a Mac OS or Linux you use export instead of set and you shouldn't see anything 10 00:00:34,480 --> 00:00:36,330 output from that. 11 00:00:36,330 --> 00:00:39,030 So here we see flasks at next. 12 00:00:39,050 --> 00:00:42,250 I'm going to say flask D-B in it. 13 00:00:42,290 --> 00:00:45,260 So I'm going to initiate my actual database. 14 00:00:45,260 --> 00:00:49,940 And if you've done that they should be able to expand this and see the migrations folder. 15 00:00:49,940 --> 00:00:53,920 So those migrations fall there and then we have these options right here. 16 00:00:53,960 --> 00:01:01,340 So the next thing I need to do is say flask and then I'm going to actually set my migrations and the 17 00:01:01,340 --> 00:01:08,430 way we do that is by typing Flast DBI migrate and then optimally you can add a message flag. 18 00:01:08,440 --> 00:01:11,870 So dash em and I would recommend that you always do this. 19 00:01:11,900 --> 00:01:17,570 So say initial migration enter. 20 00:01:17,860 --> 00:01:22,680 That's going to set the migration file and then to actually make sure everything gets run you say flask. 21 00:01:22,690 --> 00:01:27,960 The upgrade enter and now we have everything connected. 22 00:01:28,000 --> 00:01:29,430 So now we're ready to go. 23 00:01:29,440 --> 00:01:34,300 What I'm going to do is in the same folder that models that pi is in. 24 00:01:34,330 --> 00:01:37,480 So right now I have it all located under flask examples. 25 00:01:37,480 --> 00:01:44,220 I'm going to create a new file and I'm just going to call it basic dot pi and you really can call us 26 00:01:44,230 --> 00:01:45,340 whatever you want. 27 00:01:45,340 --> 00:01:56,260 So I have here now my file basic thought PI and this is a file where I'm going to create entries into 28 00:01:56,260 --> 00:02:00,550 the tables and then I'm actually going to print out the results. 29 00:02:00,550 --> 00:02:03,470 So again you can call this file pretty much whatever you want. 30 00:02:03,730 --> 00:02:09,010 So let's start off by saying from models. 31 00:02:09,210 --> 00:02:12,670 Imports then wanted to import D-B. 32 00:02:12,750 --> 00:02:17,370 I'm going to import my puppy model the owner model and the toy model. 33 00:02:17,740 --> 00:02:23,700 So I always start off by creating loops creating two puppies. 34 00:02:23,860 --> 00:02:31,120 So it's great to put the objects will say rufous is a puppy objects where we say puppy area or we need 35 00:02:31,120 --> 00:02:32,300 to pass and the puppy name. 36 00:02:32,360 --> 00:02:38,170 So say Rufus if you take a look back at the models were essentially just related to the IT method right 37 00:02:38,170 --> 00:02:38,710 now. 38 00:02:38,740 --> 00:02:44,140 So puppy just needs a name to start off with and then later on we can add owners to the puppies. 39 00:02:44,140 --> 00:02:48,270 So say Rufus is a puppy and let's make Fido a puppy as well. 40 00:02:49,360 --> 00:02:50,340 We say puppy. 41 00:02:50,500 --> 00:02:54,370 And then we pass on the name Fido next. 42 00:02:54,400 --> 00:02:57,230 I'm going to add puppies to the database. 43 00:02:57,260 --> 00:02:59,760 So the way we do that we'll say ad puppies. 44 00:03:01,150 --> 00:03:02,960 To D-B. 45 00:03:03,050 --> 00:03:08,280 Remember we can grab that database and then create a session. 46 00:03:08,350 --> 00:03:13,840 And if I have a list of objects I want to pass I can say at all in this case and want to add rufous 47 00:03:13,930 --> 00:03:21,650 and phyto they'll say D-B session and I'm going to commit those changes. 48 00:03:21,650 --> 00:03:25,010 So once those changes have been saved I'm going to check on this. 49 00:03:25,020 --> 00:03:33,490 So we'll check it by saying Prince will say puppy queery all. 50 00:03:33,720 --> 00:03:37,680 And that's going to allow us to return all the puppies in the database. 51 00:03:37,790 --> 00:03:43,910 So remember as I mentioned previously we're actually creating scripts that add new entries into our 52 00:03:43,910 --> 00:03:44,780 database. 53 00:03:44,780 --> 00:03:50,480 If you run the script multiple times you may get errors because you may be adding duplicates or trying 54 00:03:50,480 --> 00:03:52,270 to delete something that doesn't exist. 55 00:03:52,280 --> 00:03:53,110 So keep that in mind. 56 00:03:53,120 --> 00:03:58,970 I write this script in a way that's meant to be only run once I'm going to collapse my left hand tab 57 00:03:58,970 --> 00:04:01,100 here and continue on. 58 00:04:01,100 --> 00:04:08,150 So here I should see rufous and phyto and remember the puppies the way they're printed out and represented 59 00:04:08,600 --> 00:04:13,940 it should be something like Hey puppy name is Rufus and has no idea puppy name is Fido and has no owner 60 00:04:13,940 --> 00:04:14,270 yet. 61 00:04:14,480 --> 00:04:17,930 So that's what's going to be printed out when you check on all those puppies. 62 00:04:18,500 --> 00:04:22,580 So now I'm willing to just grab Rufus from the database. 63 00:04:23,000 --> 00:04:32,000 So I'll say Rufus is now equal to puppy queery so we can actually Graham are basically treating this 64 00:04:32,060 --> 00:04:40,190 as an Aurum and then I use the filter underscore by Methot off of this or the name is equal to. 65 00:04:40,550 --> 00:04:42,770 And I will say Rufus here. 66 00:04:43,610 --> 00:04:50,820 And what happens is we actually get back a list of items so one way to do this is to say first. 67 00:04:50,900 --> 00:04:54,660 So give me back the first puppy whose name is Rufus. 68 00:04:54,680 --> 00:04:57,620 And in this case it should just be this Rufus. 69 00:04:57,620 --> 00:05:03,470 If you have multiple puppies whose name you think is Rufus The other alternative is to say all. 70 00:05:03,560 --> 00:05:08,060 And I'll return a list of all the puppies whose name is Rufus and if he's just one of the first item 71 00:05:08,060 --> 00:05:11,660 off of that then you could do something like indexing to zero. 72 00:05:12,050 --> 00:05:18,880 So right now I'm just going to say give me that first puppy that I'm going to create an owner for Rufus. 73 00:05:19,090 --> 00:05:21,460 So let's create an owner object. 74 00:05:23,500 --> 00:05:31,690 I will say Jose variable is an owner and the owner has the name Jose. 75 00:05:32,040 --> 00:05:38,010 And then remember I just grabbed Rufus and Rufus is a puppy inside the database. 76 00:05:38,010 --> 00:05:41,040 It was the first puppy whose name was Rufus inside that database. 77 00:05:41,040 --> 00:05:46,700 And if we take a look back at Rufus who is a puppy Rufus object that has an ID attribute. 78 00:05:46,890 --> 00:05:53,580 And if I take a look at the owners when I create an owner and is supply the name of the owner and then 79 00:05:53,640 --> 00:05:55,130 also the puppy ID. 80 00:05:55,410 --> 00:06:00,060 So then that means I need to grab Rufus's ID or some other puppies ID. 81 00:06:00,090 --> 00:06:06,930 So since I already have Rufus as an object I'm going say that this owner's Jose and the puppy ID is 82 00:06:06,930 --> 00:06:09,230 going to be rufous ID. 83 00:06:09,390 --> 00:06:12,690 So that's the id attribute off Rufus right here. 84 00:06:12,840 --> 00:06:14,780 Who's the first puppy objects returned. 85 00:06:14,790 --> 00:06:19,960 When I filtered by name is equal to Rufus which is this puppy that I created a peer. 86 00:06:19,980 --> 00:06:28,620 So I just created owner Jose with a rufous Id not going to give some toys to Rufus So let's give Rufus 87 00:06:28,620 --> 00:06:32,740 some toys. 88 00:06:32,740 --> 00:06:38,380 Now this is a one to many relationships we can give multiple toys to Rufus so create two toys will say 89 00:06:38,380 --> 00:06:43,050 toy one and let's take a look at the method for toy. 90 00:06:43,050 --> 00:06:49,510 If we go back to models of Pi scroll up toys they have an item name and a puppy ID for who they belong 91 00:06:49,510 --> 00:06:50,350 to. 92 00:06:50,350 --> 00:06:51,380 So the first toy. 93 00:06:51,550 --> 00:06:53,640 Let's just say it's a chew toy. 94 00:06:54,900 --> 00:06:56,500 And we'll also have it belong to Rufus. 95 00:06:56,500 --> 00:07:04,440 Say Rufus thought Id And I'll create another toy object toy too and we'll say this is a toy I'll say 96 00:07:04,440 --> 00:07:11,020 it's a ball and it's also going to belong to Rufus connected by Rufus's ID. 97 00:07:11,040 --> 00:07:11,450 OK. 98 00:07:11,610 --> 00:07:14,740 So once we have all that when you commit those changes. 99 00:07:14,740 --> 00:07:19,350 So you actually commit the owners and these two toys to our database and the way we're going to do that 100 00:07:19,500 --> 00:07:26,280 is just by simply saying D-B session and then I'm going to add all and we pass and that list will say 101 00:07:26,340 --> 00:07:29,670 add Jose add toy one and add toy to. 102 00:07:29,820 --> 00:07:32,940 Notice how flexible this add all method is. 103 00:07:32,950 --> 00:07:38,400 I'm passing in different object types but the session is not going to complain because it understands 104 00:07:38,490 --> 00:07:44,460 that these particular objects relate to particular tables because they inherit from db that model. 105 00:07:44,490 --> 00:07:49,040 So a lot of that logic is taken care of for you already on the backend which is why we're able just 106 00:07:49,050 --> 00:07:52,770 to say D-B session and all of these items to my tables. 107 00:07:53,640 --> 00:07:53,910 All right. 108 00:07:53,910 --> 00:07:55,900 Once we've done that we want to commit those changes. 109 00:07:56,800 --> 00:08:03,490 Well say D-B session commit and now we're going to grab rufous again. 110 00:08:03,510 --> 00:08:10,060 So let's grab Rufus after those admissions. 111 00:08:10,780 --> 00:08:22,350 So I'll say rufous again and say Rufus is equal to puppy do a query and say filter by where the name 112 00:08:22,530 --> 00:08:24,990 is equal to Rufus. 113 00:08:25,080 --> 00:08:31,490 Let's make sure that's a stream Rufus and then grabbed the first puppy that happens to be true. 114 00:08:32,320 --> 00:08:35,270 And then print outs Rufus 115 00:08:37,990 --> 00:08:44,280 so we should expect is when you print out rufous here Rufus now has an owner attached to it Jose. 116 00:08:44,470 --> 00:08:51,900 So the first time that I print rufous in fact I'm going to rafter call him or print rufous again so 117 00:08:52,260 --> 00:08:56,370 I print both puppies I should see Rufus and phyto with no owners. 118 00:08:56,370 --> 00:09:00,660 Then I grab Rufus already from the database and I print him again by himself. 119 00:09:00,660 --> 00:09:02,650 So I should see Rufus hasna owner. 120 00:09:02,670 --> 00:09:05,300 I create the owner object create the two toys. 121 00:09:05,460 --> 00:09:07,450 Commit them and add them to the database. 122 00:09:07,590 --> 00:09:14,070 And then when I read grab Rufus from the database and I print them out then I should see from up here 123 00:09:14,460 --> 00:09:19,680 that self-taught is true meaning I should see puppy name as Rufus and owner is Jose. 124 00:09:19,740 --> 00:09:23,520 So that's what I would expect on this print statement on 9:31. 125 00:09:23,970 --> 00:09:29,190 And recall that these puppies if you go back to models they also have a report toys method. 126 00:09:29,400 --> 00:09:30,440 So I'm going to copy that. 127 00:09:30,510 --> 00:09:36,030 And then I should see here are my toys and I should see a shoe tall Go chew toy and a ball. 128 00:09:36,030 --> 00:09:36,620 There you go. 129 00:09:38,030 --> 00:09:45,850 So we're going to say Prince Rufus and we'll say report toys. 130 00:09:47,110 --> 00:09:51,820 So let's take a look at that report toys and I think right now is just printing it. 131 00:09:51,820 --> 00:09:57,460 Let's see if that works we may need to actually just make that into a return but that will probably 132 00:09:57,460 --> 00:09:57,830 work great. 133 00:09:57,850 --> 00:10:03,530 There let's say this and see if we have any issues running it say Python basic thought pi. 134 00:10:03,580 --> 00:10:07,660 So I should see a bunch of print statements enter here. 135 00:10:07,660 --> 00:10:09,270 There we go. 136 00:10:09,300 --> 00:10:14,950 So it says here puppy name is rufous and has no owner yet puppy name is Fido and has no owner yet. 137 00:10:15,300 --> 00:10:17,750 Then puppy name is rufous has no owner yet. 138 00:10:17,790 --> 00:10:23,850 Then puppy names Rufus owners Jose here at my toys chew toy and ball and at the end they got none because 139 00:10:23,850 --> 00:10:25,580 I'm kind of just printing out the results of this. 140 00:10:25,590 --> 00:10:30,400 I think this should've just been rufous that report toys because inside a model's section are returning 141 00:10:30,400 --> 00:10:32,150 anything it's already pretty enough for you. 142 00:10:32,190 --> 00:10:36,250 So we didn't need to actually say none there or we didn't need a print. 143 00:10:36,270 --> 00:10:36,840 All right. 144 00:10:36,840 --> 00:10:39,960 So that's the very basics of actually having the relationship. 145 00:10:39,960 --> 00:10:46,120 So the main things and notice here is we're able to now connect this puppy to a list of toys. 146 00:10:46,110 --> 00:10:50,110 So that's a one to many relationship and we're also able to connect an owner objects. 147 00:10:50,220 --> 00:10:54,120 And that's a one to one leader and we'll discuss more complex relationships. 148 00:10:54,150 --> 00:10:59,520 And if you're interested in them right now you can always check out the sequel alchemy code or documentation 149 00:10:59,640 --> 00:11:01,580 to get those sort of examples there. 150 00:11:01,770 --> 00:11:05,880 And as a quick reminder you can always delete things from the database by using D-B that session that 151 00:11:05,920 --> 00:11:08,580 delete and then deleting the puppy from it. 152 00:11:09,000 --> 00:11:12,030 OK so we've discussed already quite a lot of detail. 153 00:11:12,210 --> 00:11:18,090 How do create models now what we need to do is start talking about how we actually connect these models 154 00:11:18,420 --> 00:11:24,290 to the views because we haven't actually seen this in regards to a Web site. 155 00:11:24,300 --> 00:11:29,550 So now that we understand everything is going off the models the databases school light and migrations. 156 00:11:29,670 --> 00:11:34,870 Let's take all of that knowledge and connect it to what we already understand about serving templates. 157 00:11:34,980 --> 00:11:40,710 That way we can have pretty much our full functioning Web site where we're able to accept the form of 158 00:11:40,740 --> 00:11:47,680 input and then use these sort of at all and commit commands inside of our flask application to add a 159 00:11:47,700 --> 00:11:54,180 user form data into a database and then we can also read it and return it back on another page. 160 00:11:54,180 --> 00:11:58,810 So we're finally in the very next lecture actually going to start working on the most functional web 161 00:11:58,810 --> 00:12:00,160 site we've done so far. 162 00:12:00,210 --> 00:12:01,790 I'm really excited for that next step. 163 00:12:01,800 --> 00:12:04,070 It's really a huge leap forward in your abilities. 164 00:12:04,170 --> 00:12:09,000 So we'll see you in the next lecture where we begin to discuss databases in views either.