HasKey(c => new ) įinally, by convention, the index and constraint that are introduced for an alternate key will be named AK_ (for composite alternate keys becomes an underscore separated list of property names). Protected override void OnModelCreating(ModelBuilder modelBuilder) ![]() You can also follow the conversation on Twitter with the hashtag #dotNETMAUIAdvent.The attribute was introduced in EF Core 7.0. Remember to follow the rest of the interesting publications of the. In this case, I also used statements instead of the ORM capabilities (you can use both without any issues). You can check the rest of the code to see how to insert, update, and delete. Well, this was a long post but hopefully, useful for you. What do we get when we click on the menu and access the Employees item? First, this query is executed:Īnd the app shows the information from both tables. Then, counting data, inserting values and retrieving the first department (Kitchen). We can see some information in the Output window (in Visual Studio) as well as in the phone: It shouldn't be complicated to understand, but if you do have a question, write a comment and I'll do my best to help :-) In this post I'm not including the Views definition (because it is pretty obvious, just bindings) or the DetailsView/DetailsViewModel that I use to add, update, or delete information from the tables. The query is used by GetItemsAsync in the ViewModel, while the route is used for navigation.įor the rest of the code, please check the GitHub repository. Thanks to ActivatorUtilities, we can customize this definition by including the following arguments: a query and a route. ![]() There you have it! Each View will require a ViewModel, which is the same ( GenericListViewModel) with different generic type and arguments. This is the code of the four classes, in order of creation: ![]() I believe that the SQLite attributes are not necessary since we defined our tables using the statements, but it doesn't hurt to include them (I think). I also created a BaseTable class, which includes an Id property, and all classes inherit from this model. For example, the EmployeesAndDepartmentQuery query is a view since it includes fields from Employee (all) and Department (DepartmentName) tables. A view is a projection, a set of specific fields from a query that involves one or several tables. There are two types: models that work as tables, and models that work as views. Create the following classes and structure: I will not include it here, but you can take a look at the GitHub repository for the code. NOTE: In this folder, there is also a FileAccessHelper class which is used to access the database file. However, for Employees table, it is better to customize the data management. For example, you can create and get all items from Departments table with the CreateTable and Table methods because there is no foreign key involved. As you can infer, instead of using the ORM capabilities that are integrated in SQLite, you will manually execute queries! However, you can still use the ORM mapper for several operations. They limit the data that can be inserted into tables. Of course, the most important elements are the statements and queries. last modified JIn this part of the SQLite tutorial, we will work with constraints. ![]()
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