XAF XAFers Community Standup, 2 May 2023

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From YouTube: XAFers Community Standup - Querying Data in XAF

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A

All right all right, hey, welcome everyone to another, safer community stand up today. We're gonna be discussing how to query data in South as always uh join our Facebook group I think we are right now around 2000 600, almost 7 700 members really excited about that. I think I watched it posted on Facebook the other day. They was like or three years anniversary on the group, and that was the day that we actually started, and it was just Jose Jose and myself.

A

So I'm really happy to see like almost three thousand other members are here with us. uh Follow the expresso.

A

Members there and follow Twitter every new uh feature, every new module everything that is coming is the theme from the express will be posted here. So it's a good place to know what is coming, for example, in 23.1 that is going to come, the scheduler that is going to come new icons on the tops and everywhere so the example for kubernetes. So we have a lot of great things here.

A

I also, yes came back, and this is one of the reasons that today we are late and a lot of things going on, but I just came back from the global MVP Summit either cannot disclose a few things due to NDA in there, but I have to say that Blazer on the net 8 will be amazing, and one thing that I can say publicly is the issue that sometimes we have with this connection is going to be improved by a lot so more on that will follow later, but really excited about that.

A

Okay, today will be a small Meetup. We are not the managing we haven't. We have been over well with a work and the new things and stuff and projects and so on, but we didn't want to leave this month without any stand up so and we're gonna be talking about querindara and stuff and I'm gonna pass the foreign.

B

Sorry from so, let's start okay, so the topic today is querying data.

B

And we have to talk about this before and I wanted to take a different approach because, as you know, xaf uses Entity framework and xpos data source, but there are other ways to query in data. That's what I wanted to show in here.

B

So usually, if you're using a normal application, you use another an Orient right. So instead of using an orm, you have any. You have other possibilities to include data in xcf. So we did a case like a few years in my team that we use mongodb and we showed the information from mongodb into an XTF application. So that's the process. I wanted to take this in this case. So there are two places where you can start interview like uh the how xaf queried the data. So usually it will come from the optical space.

B

As you know, the object space is an interface. Well, you have the complete object space and you have the interface. That is that has a few methods that allow you to query data in in xaf, both main methods, and you have methods to create Collections and methods to find single objects, and also you can query data using link and Lambda operations. So these are the two entry points that you need to somehow overwrite enable to query data for sources. Actually, that should be the name of the standard querying data from other sources.

B

So these are the signatures of the methods that we can actually override to get data from a web service, a file, another non-relational database and so on. So here you have the link for the for all the the members of the eye object space, but these are the only ones that we need.

B

Actually, there are several overloads of this method, but these are the ones that all the base version- let's say like that: okay, so we know that we have this interface, that is the entry point to really data in xaf, and these are the two basic methods that we can override for that.

B

So the next thing that we need to do is okay. Once we have those methods there are underlying orms on that you can use in xaf uh on one side we have Entity framework and on the other side we have XPO. So in here you can see how the the.

B

Hilton Street of the object space is working because you have non-persistent Olympic spaces, XP object, space, Entity framework, big spaces, so these are the ones that we can actually overwrite or handle their events to provide to data from other sources. So in in that link, you can see actually, where I got this uh chart and the functionality of each object space so depending on which type of application are you doing, you might have one or the other or all of them, because in xaf you can include basically all the object space provider.

B

There are examples that you mix the object: space provider for Entity framework and other example that you use the object space provider for XPO.

B

So, let's move forward here and also uh between those three those Bridge methods like find, object and create collection. You can usually use criteria. Operators, okay, Theory operators are the part of developer Express because they don't exist in the Microsoft world that are um a string, expressions of something that looks like uh like a where um a word sentence. So these criteria, operators, you can use in almost every Dem Express control, but they don't exist on the link part.

B

Actually, there are some really mysterious frame or a nougat packages that you can use two parts strings and create the Lambda operations or you can do it by code. There is a Lambda.

B

Or something like that, that you can create operators and are like logical operators like on or and so on, but to be honest, the one that I like the most and the one that is kind of really really working for me is the one from developer. Express yeah I, try all the open source version of this type of libraries that you pass a string sentence and it creates a Lambda operation from it, but in the end, I always end up using the one from developer Express. So in here you can see all the possible.

B

Criteria operator so of both going going back to how we started in here, you can see all the methods and members of the ayobic space, that's the abstraction that you can use for either Entity framework or XPO, or you can create your own abstraction, and this is Wikipedia language, so in here you can see on which part of developer Express components you can use it and the constants and all the functions and operations. Basically, this is the theory on how uh where sentence actually works.

B

So I guess if you are using self or hpo for some time, you already know how they work. This kind of a really primitive language and by primitive I mean actually Advanced, because this came out in NET Framework too, because there was no link or land expression at that moment, so they have to come with their own Solution on practicing expression and so on and so forth. So we will see a a little demo later and let's go back to PowerPoint. So let's continue.

B

Here so you can use those criteria, operators to decide how you will query data in that other source that um that you want to include.

B

And okay they've seen different type of source or or implementations of the iodic space is to where well, you can use something like not include something from an RM or you can reduce the overhead of querying data but introducing Anonymous types, and you can use that with Lambda and Link I guess I don't have to explain what uh link is is basically a language through query objects um in the object-oriented way.

B

So we will see an example of that and that's how we will provide the data for the soft application that I'm going to show you later.

B

And these are some things that are actually kind of new. For me, there was a different approach to do to present in the data, but there is something that is called a dynamic collection, so this is a component that is done by developer Express and it helps you to provide other to to ah xaf application. So here I include the links for the information for the class and the example that we're going to use today. So with that I would like stop with the.

B

With the light show, I'll just go to system code, so I'm using my Mac today, because I'm traveling, so I prepared them in another computer. So let's actually go there I think I. Have it open already Yes okay. So this is an official example from developer experience. That I did a few modifications, so in this example I think I have it here on top I need to reconnect I guess, because this screen was frozen.

B

Okay so let's see I think I had GitHub here. uh Is this one?

B

So basically in these? No it's not that one.

B

About one, let me get it from the.

B

From the government.

B

Because this example is been modified lately, so I always use it before, but this is a different version and they introduced some interesting parts. So, let's go back to the remote desktop.

C

B

Here, um okay, so this is the one that we wanted.

B

Okay, so in this example, what you will see is a way that you can forward any criteria that is sent by the UI, so the UI sometimes create ideas, resources, for example, when you are in in a list View and you've printed the columns or you create a criteria that you put it in degrees that that it is being forward to the object space implementation that you have and as I told you before. If we override define object and they create collection method, you can provide data from either other sources or more.

B

If I have it's going to be query in the cases, for example, that you want to reduce the amount of properties that you're going to query and create something like more efficient query. Okay, so you can download the example from here. Mine is a little bit modified. uh Let me show you the part that we that are important in here, so the first part is actually at the module level.

B

So let's go here so uh in the modules you can wire the the setup complete event from the application and that's the perfect time to actually handle another event, which is the objective object space created. So in here we are writing the application, complete event and setup complete event and the application object space created. So in here we check if this is unknown person.

B

Big space and if it's a non-person, we will adapters. This is the part that is new in previous example. uh You don't have these these adapters and I. Guess they introduced this because of laser I, don't think they will need in Windows forms. So let's go and check the article adapter, which is the one that I'm modifying.

B

So here you get the non-persistent objective space, because in this, in this case, we're going to provide information from other sources, not from not from the orm itself. At the beginning, I show you a little bit of okay, you have the object, spaces and XP object. Spaces will provide XPO data, um Entity framework object, spaces will provide HD frame or data, and you can create your own implementation or overwrite.

B

Those implementations that I mentioned before so in this case we're using a non-persistent object space, which is the perfect uh the same component that you can use to introduce new data because in xaf you always need to have something like a model like a look like a persistent class, but it's not persist anywhere. So let me show you what models we have here more than well.

B

Actually, the actual name is domain component, but let me show you the article I think this computer is I mean my connection is not super good today, but let's see okay, we have the article here. So, as you can see, is the big this class of this article is a non-persistent based. Object is decorated with the domain component attribute so use this, because that needs to include them in the model. So it knows that you should create I mean that it should create a view for them, so you cannot introduce a poker class.

B

Even if you introduce a poker class. There are some requirements that you have to have a primary key in the class or something like a limit identifier, and it always has to be decorated in this way. So.

B

Beside that, all the models are exactly like that they have the same requirements: here's the other one that we are going to use or we are using actually example and well, let's go back to the adapters. So if we check the article adapter over there, so we wire one more event here that we can actually write on the module level. But this is the new the sign pattern that they are introducing so in here, since this is a non-persistent object space, you wire the gear, the object getting event.

B

So in this object game event, you get uh some important information which is um which type is the object space requesting? For example, when you do a final object, s want to do a fine object of customer. So that's the type that you want to query, and then you pass a criteria operator so in here you get both of them, and this is also kind of new for me, because it was a different approach before now. You have this object. That is called a dynamic collection.

B

The dynamic collection is a collection that is created like anything and it's not being loaded until actually you needed to bind it to a control. So the Constructor of the dynamic collection takes the object space. You see the type, the criteria, the sorting and, if it's in transaction or not. So this is the perfect information that you might need to query any data source like that.

B

You can imagine it can be a DB implementation, it can be I, don't know a postgres Json implementation, you name it uh here without the Constructor, you have all the information that you need to build any query. You have all the necessary information. So in here for the collection we wire one more uh event, which is fetch objects, and then we pass to the getting objects. We pass this collection also in here you can just create a list of objects and attach it to this.

B

These objects property, but uh they are doing it doing it in a different way. um In this case. So let's check the the fetch objects event.

B

So in here, uh basically, we are returning a list of Articles and you can see it here. It's a static list of articles uh is being created here in this method of space demo. Data.

B

So it means that, as long as you pass the list of the type that uh because space is the coin, it will be shown on the UI level and also in here you can do something extra, depending on which type of object space are you using or which type of implementation you want to do. For example, in here in the more simple case, uh we just passed the list of Articles and we say see the um that this event is being handled like shape. Data equals true, but also you can do something like this.

B

If you want to reduce the overhead as I mentioned in the PowerPoint, uh basically you you can query the objects and say: okay, I just want to do a select new and when you do I select new of our collection. If you're using an orm, for example XPO, uh you will query only the properties that you include on the select Neo, which means um the only values that you will see are the ones that you do in this part in the in the select.

B

So if you have a class with 1000 columns or properties and in the select new, you only include two of them. um Only those two will be included in the query, so you will receive less data from the data from the database and, of course, that will make it faster and also you can do something like take. You want to get just the top 10 top 20 or whatever.

B

So this is how you can um basically reduce the overhead loading data if you are using an orm if you're using something like a web service, uh then it's up to you to decide how you will feel the ease this list. So, let's.

B

Kind of really simple example, but what I like is that it helps you to introduce other data sources to soft, not only XPO or anything. So let's run this one.

B

B

You will see here and put a breakpoint if my connection allows it.

B

Okay, so let's.

B

Application to load- let's see, usually you know the demo effect. My connection was good like one hour before.

B

So, let's wait a little bit for this to load.

B

And okay right now.

B

Going to see but again the demo effect. So let's stop this.

B

Okay: let's try it again.

B

And let me check if we have the perfect point.

C

Show me God: yes,.

B

Okay, so here is requesting the first set of data, because the first this view that is selected is the article is view. So here we have 70 articles that were randomly generated in with this code.

B

So let's continue.

B

uh And if we open here uh this is the data that didn't come from either Entity framework or XPO. It's just a simple array of objects that you can actually feel in any way that you want. So now. Let's say that you want to fill this or reduce the amount of objects that you have. What I did is like I did that, if statement, so, if there is a criteria attached to this Dynamic collection, page uh page, oblique event,.

B

uh It would enter here and here what we're doing is. Basically, we are just taking 10 objects out of those 70s. We are you're using two properties, and actually there should be more properties than that, but uh I mean you have to have a bigger object for this to make sense. But this is a really simple example.

B

We are just mapping two properties and the only one that is required is the actual article ID, because you need to have something like a unique value in order to show so, let's go here if it doesn't take forever to click. I'll just put, let's put a break from here, so we can see that we enter the the if statement. So if I do it here and then I click.

B

You will see that okay, in this case, we have the Criterion. It's a contains criteria, so you can use that to query. You know mongodb and data source that you're using to fill these objects, and also you can um you can use it to reduce the amount of properties that you want to query like we're doing here.

B

Let's run this.

B

And, of course, it's not taking anything uh demo fight, so let me just do a small change in this case. This is what I wanted to show, but um just to see that this is entering this event.

B

Let's remove this comment, unless you is a small subset of objects,.

B

I, don't know if you can hear the church but I'm in front of a church here in Italy. That's why um uh you you might hear it.

B

At this comment, this out don't see the comment. These are when you're, not using your computer.

C

This comment is out.

B

On this, video use, this smaller subset of objects with take and then pass a list to it. So, let's on it so when I create something that sends a criteria to.

B

uh What is wrong here see.

B

Well, I can delete this part actually I.

C

B

On this one, so let's use just a small subset.

B

Okay, so this is the first time that enters is showing the the first list. View.

B

And if I try to filter this is where you can manipulate the the subset of objects that you want to return so when I hit here, I will just see them because I don't know why the query that I I row there is not working right now. I guess it's a demo effect but see right now is um more pages of objects, and now we have only only one page. So in conclusion, this is how you can query other data sources in xaf.

B

You can Implement your own version of the your own, your own object space provider, your own object, space, override the implementation of create collages or find objects.

B

Or basically, just um go with the non-persistent object space And, depending on the type that you want to show against from any source that you want like a web service. uh Non-Sql object, I mean non-sql database.

B

So, uh as you can see, itself is not only XPO or LED framework. uh You can provide any type of data to an xcf application, so that was the demo and, let's see maybe someone has a question.

A

There is no questions in the chat. That's about uh I think that it shows the possibilities that we have with staff that we can query relational data. We can load that on demand, we can load the only portion of data and we can connect to different data sources, web services and you and any other.

A

So it's just really extensive, so I have a I know that today we're doing a smaller Meetup, but I have like a couple of small demos. I want to show briefly just to perfect two percent, and then we go from there. Okay, the first one that I want to present is an integration. uh We have had these questions from a couple of other students and clients a couple times about Integrations of custom components and I. Think this one is a really good example.

A

This is an integration of the dxtreme map and basically, we have here a company, sorry with two locations, a test, location and Washington with two latitude and longitude. So we have a site and that side that is Ho Chi has a location that is in Washington as well. If we open that one, we see that we have a property editor that takes that lateral, logitude and present them up and, of course, with a a little marker. And if you go to company, this is a property either it's just a property on the little View.

A

But if we go to company and we open company- and we know that service companies have two locations and we click on, then you see that this is a list editor that which will remove all the actions, New link and so on, because this is no don't apply here. But basically you see that we have two markers and we have the DF extreme map running on the system and it looks really nice.

A

So if we look at the code for just a second, we know that we have a component that basically is just a deep of ID map, and then we have a JavaScript that take care of the red that takes that a element ID map and then create a map instance. And if you see here, you can put your provider key here. Right now for being, is not needed and then we can use that anywhere in your application. So we can have a list editor, that's what we saw with the company.

A

This is a listener inside the company, okay,.

A

Of that a map integration or we can have a property either, and this property either is the one who take care of this data View Property, and then there are all the implementation, like the other string, map needs and you're gonna start uh creating all the the layers that are properties, foreign.

A

From that- and it will take that implementation- so that's the first one just to show I- think a integration with a custom controller I think this one is one that the people ask a lot about presenting things in a map control and now, let's see another quick example, and without we will finish your middle from April month, we didn't want to leave it. So let's do this one first. This is one of us doing, asking us how to put extra fields in the security.

A

So basically we have a question. Logon parameters and we're gonna, add a Boolean field and we're not gonna be able to log in. If we don't have that Boolean field check and with that a personal loan parameter, we're gonna, take or create a custom authentication standard that it will take that awesome, Authentication and then inside that in the authenticate, we're gonna make sure.

A

It has to be true if we run this.

A

And let's give it a second.

A

It's coming, you'll see that we have this Market something to login and we had and just to mentioning. But actually, if we want to have the text on the right side, we have a let's find that it controller that actually customized, that property either and put the label position to the right, and we hide the text that that property has just to make. It look like this so right now, if we try to log in without marking that it will throw on a section that you need to mark that to login.

A

So this was the first example to be able that we have an extra not secure at all, but an extra level of an extra parameter in the the security system. Now, taking this a example and improving on that, we will have then a more useful one that is actually the whole goal is now that we understand that we can create a custom parameter and create a custom authentication and make sure that ensures that that extra property have to be filled to login.

A

Now we can put something like Google capture and Google capture actually send us back a response when we uh executed, so we can use that the same way that we use that Boolean field to make sure that if there is no Brute Force attack in your side, that there is not that if there is not that level of security that someone does the culture before logging in, you won't be able to do it. So, let's give it a second.

A

Almost there and now we have a culture here so now, if we try to login without the culture, we'll do the same thing.

A

It will fail because it doesn't have the the culture enabled and now well now, I failed before, because we didn't have the user. So let's do it again, complete the captcha and now, if we click here, it will validate that we are actually a person with another robot and we will be able to login.

A

Now, let's take a quick look at the code and this will login perfectly and we can see it again. We have the JavaScript for the Google capture part and we have our Tracer component, that by sales Json ID with the Google captcha, and then we have all four layers and we're gonna have a property editor and everything is Success. We show the authentication standard provider with the awesome authentication with a question, long parameters and then we'll have extreme culture and that's what the global culture returns and then your property, and that's it.

A

If we see these examples, what improved is the possibilities that we have which have the based on? If wearing a list view or representing a collection of data, we can create list if we are doing it just for a property Properties or if we're doing things that are not tied to any other. We can use dashboard view or view items and go from there. So, uh okay, that will be all for my site. uh I appreciate everyone who joining this Meetup. We didn't want to leave April without anyone.

A

So thank you so for coming and we'll see you next month, I think that next month will be a great one, because we're gonna we're already the nearly preview for 23.1, but the next one will be a the actual 23.1 with everything that is coming so I think that a lot of great things are coming. So thank you for coming and see you in the next one. Bye.