Entity Framework Fluent API

Entity Framework Fluent API

Then, we create a single master class that implements all interfaces, so its methods can simply return the this instance. That way, we not only concentrate the API logic in a single class, but we also avoid multiple object instantiations in a single chain. This alternative design still gives the benefits of a fluent API, assuming the master class is not visible to the user. A relationship, in the context of databases, is a situation that exists between two relational database tables, when one table has a foreign key that references the primary key of the other table. When working with Code First, you define your model by defining your domain CLR classes. By default, the Entity Framework uses the Code First conventions to map your classes to the database schema.

You can refer to this link to the repo containing the full code for this class. This would let the object either call the same methods again or use the WithCommand method to short circuit and get out of the loop. Here each method would be returning the same object and at last the GenerateDockerFile() would return the text content of the docker file. If you want to see the final result, you can check this repo containing all the code that we are going to write. The intention of designing a ‘fluent’ API is to produce an API that is readable and flows.

Unfortunately, the fluent API implementation may end up messy and unmaintainable, because it is composed of multiple classes. If two FSM edges have the same label, then we have to encode them as identical methods in two different API classes. Also, as fluent methods may not return the class they are contained in, they have to instantiate a new object, and pass it any intermediate data collected in the chain. Both of these problems can be solved by encoding fluent API states as interfaces, rather than classes.

It allows you to configure default database schema to be used for tables. This schema name used for all database objects which do not have explicit schema name. Since I wrote this post this term’s been used rather widely, which gives me a nice feeling of tingly gratification. I’ve refined my ideas about fluent interfaces and internal DSLs in the book I’ve been working on. I’ve also noticed a common misconception – many people seem to equate fluent interfaces with Method Chaining.

The Fluent Interface pattern is useful when you want to provide an easy readable, flowing API. Those interfaces tend to mimic domain specific languages, so they can nearly be read as human languages. When columns must have values you can mark those columns as NOT NULL. Entity Framework code first should configure such properties with the IsRequired()method. If application tries to insert/update record with NULL values Entity Framework throws DbEntityValidationException. Probably the most important thing to notice about this style is that the intent is to do something along the lines of an internalDomainSpecificLanguage. Indeed this is why we chose the term ‘fluent’ to describe it, in many ways the two terms are synonyms.

Add new related records to an existing record

A introductory post talking about fluent apis, its pros and cons and how to design one for yourself from scratch. Besides, of course, proper documentation, the usability of an API is greatly influenced by its design. In this post we discuss fluent APIs, which are produced by a funky and popular design technique. We learn what fluent API is, how it benefits the programmer, and how to compose expressive fluent APIs.

Yet, the truly fascinating feature of Startup CTOs in static languages is their ability to enforce API protocols at compile-time. An application programming interface makes it possible to access an application from within code. In this context, an application can be a single class, a software library or module, an external tool or service , or even a physical artifact .

In Python, returning self in the instance method is one way to implement the fluent pattern. In Raku, there are many approaches, but one of the simplest is to declare attributes as read/write and use the given keyword. The type annotations are optional, but the native gradual typing makes it much safer to write How to Become a Data Analyst directly to public attributes. A common use of the fluent interface in C++ is the standard iostream, which chains overloaded operators. C# uses fluent programming extensively in LINQ to build queries using “standard query operators”. The following table lists important methods for each type of configuration.

Fluent API Configuration

The price of this fluency is more effort, both in thinking and in the API construction itself. The simple API of constructor, setter, and addition methods is much easier to write. After representing the protocol with an FSM, we can directly implement it in a fluent API. We turn every state into a class, and each edge into a method; given an edge labeled f from state X to state Y, we add method f() to class X and give the method the return type Y. To every accepting state, we also add terminating methods (build()).

You can configure data models using Data Annotations or Fluent API. Data Annotations gives the only subset of configurations, Fluent API provides full set of configuration options available for code first. In this blogpost explains how to configure entities using Fluent API of Entity Framework Core or EF6 above versions for the Code First approach. This will give you details about how to configure business rules with Fluent API methods for PrimaryKey, Unique, Index, Required, Identity, etc. Provide transactional guarantees for creating, updating or deleting data across multiple tables in a single Prisma Client query. If any part of the query fails , Prisma Client rolls back all changes.

• I haven’t seen a lot of fluent interfaces out there yet, so I conclude that we don’t know much about their strengths and weaknesses.
• If the user is not well versed in the domain, they would be lost trying to combine enigmatic methods, stitching things together until they work.
• In this example two implementations of a FluentIterable interface are given.
• One is the entry method like CreateBuilder() above or Initialize().

I’ll continue with the common example of making out an order for a customer. A line item can be skippable, meaning I’d prefer to deliver without this line item rather than delay the whole order. These benefits may seem superflous or not worth the effort required to build such an interface API and I totally get that.

Explains how to configure entities using Fluent API of Entity Framework Core or EF6 above versions for the Code First approach. Now in the Dbcontext class, it’s necessary to override the method OnModelCreating. Inside this method, we are going to set the configuration for the entities using Fluent API. If you want to know more about how can you create the structure of your project, you can check the article “Creating an Application from Scratch using .NET Core and Angular — Part 1” clicking here.

Creating A Fluent API In C#.NET

Learn about facades design pattern and how to use them in Sitefinity CMS CSS Inliner Tool Email Design Reference. It is another layer, which can be described as a wrapper of the all manager classes that a developer would usually use in order to create content, pages, classification units or users. The example uses a nested include to include all posts and post categories. In 3.0.1 and later, you can include or select a count of relations alongside fields – for example, a user’s post count. In essence we create the various objects and wire them up together.

If you want to specify the join table name and the names of the columns in the table you need to do additional configuration by using the Map method. In the following example, the Course Title property is required so IsRequired method is used to create NotNull column. Similarly, Student EnrollmentDate is optional so we will be using IsOptional method to allow a null value in this column as shown in the following code. When the database is generated, you will see the tables name as specified in the OnModelCreating method.

Composite Primary Key

These classes are then added to the DbModelBuilder’s configuration in the OnModelCreating method. Prior to version 2.0 of Entity Framework Core, there was no equivalent to this approach and one had to roll one’s own solution. In the above example, the HasRequired method specifies that the Student navigation property must be Null. So you must assign Student with Enrollment entity every time you add or update Enrollment. To handle this we need to use HasOptional method instead of HasRequired method.

We also show the applicability of fluent APIs to domain-specific languages. You can see when the database is generated, the table and columns name are created as specified in the above code. Below are the Student and Enrollment which has one-to-many relationship, but the foreign key in Enrollment table is not following the default Code First conventions. So rather than going into the domain classes to add these configurations, we can do this inside of the context. Override the OnModelCreating method and use a parameter modelBuilder of type ModelBuilder to configure domain classes, as shown below.

DataType

This post will introduce these Fluent APIs, share some common benefits and pitfalls of using such an API and a short tutorial on how to design such a class yourself. Here you can see that every function returns the existing class in order to create a Fluent API chain. However, the final function “GetData” returns the main expected value. In this article we will look at creating a Fluent API class in C#.NET. In a Fluent API, we can link together different functionalities to get a particular result. We see this used many times in Entity Framework Core and when manipulating List type of items using lambda expressions.