, WithRequiredPrincipal(), Specification of inheritance mapping (Table-Per-Hierarchy, Table-Per-Type, Table-Per-Concrete-Class) between object model and database tables, .Map(Action> ), (Quote from here) Microsoft views the Fluent API as a "advanced feature". If you are using an earlier version the information in this section does not apply. 503), Mobile app infrastructure being decommissioned, 2022 Moderator Election Q&A Question Collection, Entity Framework Code First Foreign Key issue, entity framework code first attributes in combination with fluent api configurations. Which was the first Star Wars book/comic book/cartoon/tv series/movie not to involve the Skywalkers? The usage of annotations and the Fluent API may be combined at will. For example: If you put the, MinValue is an attribute that cannot be defined via Fluent API (Programming Entity Framework: Code First) (source: deleted NAA by, From a architectural point of view, I guess. Fluent works when you can't modify the classes. Code First gives you two ways to add these configurations to your classes. All properties of Department will be mapped to columns in a table called t_ Department. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Press question mark to learn the rest of the keyboard shortcuts. When the migration is complete, you will access your Teams at stackoverflowteams.com, and they will no longer appear in the left sidebar on stackoverflow.com. How does cookie based authentication work? Index attributes are processed by including a model annotation on the model that is then turned into an Index in the database later in the pipeline. Sometimes, however, you cannot or do not want to follow those conventions and need to map entities to something other than what the conventions dictate. Does it offer the same degree of 'tweaking' as Fluent API or should I be leaving the domain model alone and separate all of this 'tweaking' to separate Fluent API classes for each domain model object? (requires less code, and all is in one place), @CounterTerrorist: I don't think so. Data annotations are a subset, and don't for example include cascading delete for relationships. Return Variable Number Of Attributes From XML As Comma Separated Values, Field complete with respect to inequivalent absolute values. The easiest way to do this is to create an instance of IndexAttribute that contains all the settings for the new index. SSH default port not changing (Ubuntu 22.10). Fluent offers features not exposed through DA. Why are taxiway and runway centerline lights off center? To see all the basic instructions and complete navigation for this series, visit Entity Framework Core with ASP.NET Core Tutorial. Fine granular tuning of relationships, especially in all cases where only one side of an association is exposed in the object model: .WithMany(), WithOptional(), WithRequiredDependent(), WithRequiredPrincipal(). For more details see, Code First Insert/Update/Delete Stored Procedures. Allow Line Breaking Without Affecting Kerning. You can also specify the schema name like this: In the TPH mapping scenario, all types in an inheritance hierarchy are mapped to a single table. In other words, there are certain model configurations that can only be done using the fluent API. Fluent API Configurations in EF 6. The annotations only cover a subset of the fluent API functionality, so there are mapping scenarios that cannot be achieved using annotations. is called, the prior co. .net c# ef-fluent-api entity-framework entity-framework-6. In some cases the key values can be converted to a supported type automatically, otherwise the conversion should be specified manually. Entity splitting uses multiple calls to the Map method to map a subset of properties to a specific table. 2. Data annotations and the fluent API can be used together, but Code First gives precedence to Fluent API . Can be done with any number of other things, too. Also, you may consider polluting your models with persistence logic such as database column names inappropriate. Super clean to have .sql scripts formally design your database and reverse engineer class files with attributes; bypasses migrations too. Want to improve this question? When working with Entity Framework Code First the default behavior is to map your POCO classes to tables using a set of conventions baked into EF. rev2022.11.7.43013. unless your requirements require you And if you program against interfaces a lot of your classes might share some common attributes so you can implement the interface and then your config classes can have some shared configurations for those interfaces that should all be set up similarly. How to help a student who has internalized mistakes? Fluent offers features not exposed through DA. rev2022.11.7.43013. add an XmlRepository and use the same Model classes). When the key isn't available in your object model, provide the name of the foreign key column in the database: .Map(conf => conf.MapKey("MyForeignKeyID")). The options on the configuration object are specific to the type being configured; IsUnicode is available only on string properties for example. Entity Framework Code First - Advantages and disadvantages of Fluent Api vs Data Annotations [closed], github.com/borisdj/EFCore.FluentApiToAnnotation, Stop requiring only one assertion per unit test: Multiple assertions are fine, Going from engineer to entrepreneur takes more than just good code (Ep. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. If a derived type includes a required property the column cannot be made non-nullable since not all types in the hierarchy will have this property. Entity splitting allows the properties of an entity type to be spread across multiple tables. The following example configures the DepartmentID and Name properties to be the composite primary key of the Department type. If Code First creates a database from this model then the column used to store this property will usually be non-nullable. MapInheritedProperties remaps all properties that were inherited from the base class to new columns in the table for the derived class. The Fluent API allows you to customize anything that DataAnnotations allows. Setting the property to be a row version automatically configures it to be an optimistic concurrency token. Traditional English pronunciation of "dives"? Identity is the default value for integer key properties when working with Code First. In a current project, I make use of both, as needed.. Stack Overflow for Teams is moving to its own domain! While EF Core supports using properties of any primitive type as the primary key, including string, Guid, byte [] and others, not all databases support all types as keys. The following example sets the DepartmentID property to System.ComponentModel.DataAnnotations.DatabaseGeneratedOption.None to indicate that the value will not be generated by the database. Therefore, the Fluent API is "superior" from the perspective of setup possibilities and flexibility. More info about Internet Explorer and Microsoft Edge, Code First Insert/Update/Delete Stored Procedures, Your class defines a property whose name is ID or Id, or a class name followed by ID or Id. Why was video, audio and picture compression the poorest when storage space was the costliest? A significant portion of the database model may be retrieved from the code when building a database using Entity Framework code-first. Using this method does not enable you to perform any conversion of the data at run time. 4 Data Annotations let you actually see how your ORM is configured without digging through a multi- thousand line function. python. Complete Playlist: https://www.youtube.com/playlist?list=PLX4n-znUpc2aiVE9O0DfgEsSTDuR7VsrtFluent API is an advanced way of specifying model configuration th. What are the advantages and disadvantages of Fluent API in comparison to Data Annotations? The fluent API is considered a more advanced feature and we would recommend using Data Annotations unless your requirements require you to use the fluent API. Something that is either complex or will grow in complexity, setting it up using fluid can save some headaches later. Call the MapInheritedProperties method to configure each derived type. By accepting all cookies, you agree to our use of cookies to deliver and maintain our services and site, improve the quality of Reddit, personalize Reddit content and advertising, and measure the effectiveness of advertising. By using it, we can configure many different things, as it provides more configuration options than data annotation attributes. 1. Data annotations and the fluent API can be used together, but precedence of Fluent API > data annotations > default conventions. Are witnesses allowed to give private testimonies? Examples of configurationscertainly not an exhaustive listthat are feasible with the Fluent API but not (as far as I can tell) with DataAnnotations. Using some Interfaces to help make configurations easier with a lot more shared logic can ease some of the challenges of going that route, too. CodeProject If you consider the DDD architecture designs, one thing you must fulfill that is isolation our Domain Model Layer. I generally use da when I can and fluent for things da can't do. You can specify multiple index annotations on a single property by passing an array of IndexAttribute to the constructor of IndexAnnotation. Currently you cannot overwrite the conventions (only disable them; MS announced to give configuration options for the conventions in future EF releases). The conventions cannot currently be changed (only disable them; MS announced to give configuration options for the conventions in future EF releases). Relationships should be fine-tuned, particularly when just one side of a connection is visible in the object model: .WithMany() In my last big project I wanted to use DA, at the end I end up with some DA and a lot of fluent because not everything can be done in DA and even if so, it's sometimes way faster to go with fluent rather than trying to figure out DA. But if you don't want to be forced by the mapping conventions when you define your object model, your only option then is the Fluent API. Not the answer you're looking for? However, if you abandon all of your customs at once,.OnModelCreating. Everything what you can configure with DataAnnotations is also possible with the Fluent API. In other words, even if in certain situations both methods can be used, in what cases should one method prevail above the other? Data Annotations attributes are .NET attributes which can be applied to an entity class or properties to override default CodeFirst conventions in EF6 and EF Core. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Just an idea: What I usually do is create a Model project with my POCOs, and then in the Repository project, create a new set of POCOs specifically for EF, and put my annotations there. For example, when using a TPH inheritance strategy data for multiple types is stored in a single table. Does protein consumption need to be interspersed throughout the day to be useful for muscle building? You can manually add these same annotations using the Fluent API. This includes customizing the index name, creating unique indexes, and creating multi-column indexes. Specification of inheritance mapping between object model and database tables (Table-Per-Hierarchy, Table-Per-Type, Table-Per-Concrete-Class): .Map(Action> ). Or do I have to handle this manually? How to split a page into four areas in tex, A planet you can take off from, but never land back. If you choose not to define a foreign key on a CLR type, but want to specify what name it should have in the database, do the following: By default strings are Unicode (nvarchar in SQL Server). The following samples are designed to show how to do various tasks with the fluent api and allow you to copy the code out and customize it to suit your model, if you wish to see the model that they can be used with as-is then it is provided at the end of this article. When creating a database using Entity Framework code-first, a lot of the database model is can be extracted from the code. Fluent does give you a lot more flexibility, and is totally worth learning. Which finite projective planes can have a symmetric incidence matrix. In other words, under what circumstances should one approach take precedence over the other, even if both may be employed in certain circumstances? The following example maps the Name CLR property to the DepartmentName database column. But in my opinion you reach the limitations of DataAnnotations very quickly (except perhaps for extremely simple object models). But in my opinion you reach the limitations of DataAnnotations very quickly (except perhaps for extremely simple object models). You can download the source code for this article on our GitHub repository. For my next project I am definitely going for fluent, I will just have to figure out how to do it nicely and more readable. When creating your model with Code First, TPH is the default strategy for the types that participate in the inheritance hierarchy. This article is designed to demonstrate how to use the fluent API to configure properties. In the following example, the HasKey method is used to configure the InstructorID primary key on the OfficeAssignment type. Creating indexes isn't natively supported by the Fluent API, but you can make use of the support for IndexAttribute via the Fluent API. The HasColumnType method enables mapping to different representations of the same basic type. Fluent API specify the model configuration that you can with data annotations as well as some additional functionality that can not be possible with data annotations. Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support. In the following example, the Name property should be no longer than 50 characters. How can I jump to a given year on the Google Calendar application on my Google Pixel 6 phone? Note By convention, an index is created in each property (or set of properties) that are used as a foreign key. But in my opinion you reach the limitations of DataAnnotations very quickly (except perhaps for extremely simple object models). Data Annotations And Fluent API : https://goo.gl/z7GMC7 EF6.1 Onwards Only - The Index attribute was introduced in Entity Framework 6.1. Why are standard frequentist hypotheses so uninteresting? Fluent API uses the Modelbuilder instance to configure the domain model. One is using simple attributes called DataAnnotations, and the second is using Code First's Fluent API, which provides you with a way to describe configurations imperatively, in code. PsychManMagicHead 3 yr. ago If Code First creates a database from this model it will also set the maximum length of the Name column to 50 characters. to use the fluent API. I now prefer Annotation, with EFCore and additional libraries. These can then be passed to the HasColumnAnnotation method on the Fluent API, specifying the name Index for the annotation. Connect and share knowledge within a single location that is structured and easy to search. 3. Properties that belong solely to a base type or derived type are stored in a table that maps to that type. There are two ways to configure scalar properties on a complex type. We can also override the default Conventions of Entity Framework Core using Fluent API when targetting the database schema as Fluent API has higher precedence than conventions and data annotations. Entity Framework Core Fluent API is used to build model based on entity classes. Starting with EF6 you can use the HasDefaultSchema method on DbModelBuilder to specify the database schema to use for all tables, stored procedures, etc. What does it mean 'Infinite dimensional normed spaces'? The Entity Framework convention for primary keys is: To explicitly set a property to be a primary key, you can use the HasKey method. There are some scenarios where Code First will not detect a complex type (for example, if you do have a property called ID, but you do not mean for it to be a primary key). You can also use the dot notation to access a property of a complex type. Is there a way to do the above using Data Annotations? We can configure many different things by using it because it provides more configuration options than data annotation attributes. What is this political cartoon by Bob Moran titled "Amnesty" about? Find all pivots that the simplex algorithm visited, i.e., the intermediate solutions, using Python, Database Design - table creation & connecting records, Replace first 7 lines of one file with content of another file. What are some tips to improve this product photo? What is this political cartoon by Bob Moran titled "Amnesty" about? You can call Property on ComplexTypeConfiguration. Fluent API is an advanced way of specifying model configuration that covers everything that data annotations can do in addition to some more advanced configuration not possible with data annotations. Entity Framework Core Fluent API configures the following aspects of a model: Model Configuration: Configures an EF model to database mappings. When working with Entity Framework Code First the default behavior is to map your POCO classes to tables using a set of conventions baked into EF. Connect and share knowledge within a single location that is structured and easy to search. Can I replace some of this with the Fluent Api? Entity Framework Fluent API is used to configure domain classes to override conventions. Data Annotations let you actually see how your ORM is configured without digging through a multi- thousand line function. I would recommend the fluent API. The following Code First model is used for the samples on this page. So, from the viewpoint of configuration options and flexibility the Fluent API is "better". The final option is to use the default mapping conventions if you can no longer fine-tune your model using DataAnnotations (by naming your properties according to those rules). If you cannot fine tune your model with DataAnnotations anymore your last resort is to follow the default mapping conventions (by naming your properties according to those rules). , WithOptional() Entity Framework Core 6, nullable strings, and functions. Hence, we may have to fall back to Fluent API to create the Composite Key. In Entity Framework Core, the ModelBuilder class acts as a Fluent API. Note: Data annotations only give you a subset of configuration options. Attribute (Data Annotations) vs Fluent Configuration So the first thing you notice when you pick up EF Core is that half the documentation tells you you can simply add an attribute to any entity to mark it as required : lots of common things you shouldnt need the same configurations for repeatedly. Find centralized, trusted content and collaborate around the technologies you use most. The following example maps two entity types that share a primary key to one table. What does the capacitance labels 1NF5 and 1UF2 mean on my SMD capacitor kit? We are going to use all three ways: by Convention, Data Annotations, and Fluent API, to create those relationships. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. The code first fluent API is most commonly accessed by overriding the OnModelCreating method on your derived DbContext. What was the significance of the word "ordinary" in "lords of appeal in ordinary"? When the migration is complete, you will access your Teams at stackoverflowteams.com, and they will no longer appear in the left sidebar on stackoverflow.com. Edit: Microsoft considers the Fluent API as an "advanced feature" (Quote from here): The fluent API is considered a more recommend using Data Annotations In the following example, the Department entity is split into two tables: Department and DepartmentDetails.