For your purposes, it is a light hearted look at manipulating sequences of data. The application you'll build constructs a card deck and then performs a sequence of shuffles, writing the sequence out each time. You'll also compare the updated order to the original order. This tutorial has multiple steps. After each step, you can run the application and see the progress. For download instructions, see Samples and Tutorials. NET core. You can find the installation instructions on the.
NET Core Download page. The descriptions below use Visual Studio Code which is an open source, cross-platform editor. However, you can use whatever tools you are comfortable with. The first step is to create a new application. Open a command prompt and create a new directory for your application. Make that the current directory. Type the command dotnet new console at the command prompt. This creates the starter files for a basic "Hello World" application.
If you've never used C before, this tutorial explains the structure of a C program. You can read that and then return here to learn more about LINQ. Before you begin, make sure that the following lines are at the top of the Program.
If these three lines using statements aren't at the top of the file, our program will not compile. Now that you have all of the references that you'll need, consider what constitutes a deck of cards.
Commonly, a deck of playing cards has four suits, and each suit has thirteen values. Normally, you might consider creating a Card class right off the bat and populating a collection of Card objects by hand. With LINQ, you can be more concise than the usual way of dealing with creating a deck of cards. Instead of creating a Card class, you can create two sequences to represent suits and ranks, respectively.
Place these underneath the Main method in your Program. These two methods both utilize the yield return syntax to produce a sequence as they run.
Now, use these iterator methods to create the deck of cards. Here's a look at it:. The multiple from clauses produce a SelectMany , which creates a single sequence from combining each element in the first sequence with each element in the second sequence. The order is important for our purposes.
The first element in the first source sequence Suits is combined with every element in the second sequence Ranks. This produces all thirteen cards of first suit. That process is repeated with each element in the first sequence Suits. The end result is a deck of cards ordered by suits, followed by values. It's important to keep in mind that whether you choose to write your LINQ in the query syntax used above or use method syntax instead, it's always possible to go from one form of syntax to the other.
The above query written in query syntax can be written in method syntax as:. The compiler translates LINQ statements written with query syntax into the equivalent method call syntax. Therefore, regardless of your syntax choice, the two versions of the query produce the same result.
Choose which syntax works best for your situation: for instance, if you're working in a team where some of the members have difficulty with method syntax, try to prefer using query syntax. Go ahead and run the sample you've built at this point. It will display all 52 cards in the deck. You may find it very helpful to run this sample under a debugger to observe how the Suits and Ranks methods execute. You can clearly see that each string in each sequence is generated only as it is needed.
Next, focus on how you're going to shuffle the cards in the deck. The first step in any good shuffle is to split the deck in two. Place them underneath the foreach loop:. However, there's no shuffle method to take advantage of in the standard library, so you'll have to write your own. EF Core already supports querying data from stored procedures. This feature will allow mapping the inserts, updates, and deletes generated by SaveChanges to stored procedures in the database.
Tracked by Issue Use C structs or classes as value objects. It was previously the team view that owned entities, intended for aggregate support , would also be a reasonable approximation to value objects. Experience has shown this not to be the case. Therefore, in EF7, we plan to introduce a better experience focused on the needs of value objects in domain-driven design. This approach will be based on value converters rather than owned entities.
This work is initially scoped to allow value converters which map to multiple columns. We may pull in additional support based on feedback during the release. Tracked by Issue Support more types of value generation with converters. Value proposition: DDD-style encapsulated key types can make full use of automatically generated key values.
EF Core 6. We plan to generalize and expand this support in EF7. NET or using third-party libraries. Currently raw SQL queries must return a type in the model, either with or without a key defined. Tracked by Issue Code templates for scaffolding entity types and DbContext from an existing database.
Value proposition: The code generated by dotnet ef database scaffold can be fully customized. We frequently receive requests to adjust the code generated when scaffolding reverse engineering from an existing database. We plan to address these requests in EF7 by supporting T4 templates for the generated entity types and DbContext.
Developers will be able to customize the standard templates, or create new templates from scratch. Much of the work planned for EF7 involves improving the data access experience for.
NET across different platforms and domains. This involves work in EF Core where needed, but also work in other areas to ensure a great experience across. NET technologies. This list is based on many factors, including customer data, strategic direction, and available resources. The general areas we will be working on for these platforms are outlined below. Value proposition:. NET Framework applications using distributed transactions can be ported to. The System. Transactions library in.
This code was never ported to. NET Core. In the. NET 7 timeframe, we plan to investigate and begin the process of bringing this functionality to modern. This will be initially for Windows only, and will support only database scenarios where the ADO. NET provider also supports distributed transactions. Other uses of distributed transactions, such as in WCF, will not be supported in.
Value proposition: dotnet ef commands are easy to use and work with modern platforms and technologies. NET platforms have evolved since we first introduced tooling for migrations, database scaffolding, etc. In EF7, we plan to update the tooling architecture to better support new platforms, like.
This includes providing better feedback when things go wrong, better integration with logging, performance, and new sugar. Tracked by Issue Improve experience for data binding and graphical interfaces. EF Core is designed to work well with data binding scenarios, such as those in Windows Forms and.
However, connecting the dots between these technologies is not always easy. Tracked in the. NET Data Lab repo. NET applications. SqlClient is a fully-featured ADO. It supports a broad range of SQL Server features on both. NET Core and. However, it is also a large and old codebase with many complex interactions between its behaviors. This makes it difficult to investigate the potential gains that could be made using newer. NET Core features.
We began a project last year, colloquially known as "Woodstar", to investigate the potential for a highly performing SQL Server driver for. We plan to make significant further investment into this project in the EF7 timeframe. Investment in Microsoft. SqlClient is not changing. It will continue to support new SQL Server features as they are introduced. Tracked by issues labeled with 'area-cosmos' and in the 7. We made significant improvements to the EF Core Cosmos database provider for the 6.
Finally, a more advanced sample: determining if the values of the properties of two instances of the same type are equal Borrowed and modified from this StackOverflow post :. In other words, a regular LINQ expression can be trivially parallelized across any number of threads. This is accomplished via a call to AsParallel preceding the expression.
This code will partition facebookUsers across system threads as necessary, sum up the total likes on each thread in parallel, sum the results computed by each thread, and project that result into a nice string. For jobs that do have a side effect, consider using the Task Parallel Library. Skip to main content. This browser is no longer supported.
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