fluent api in entity framework core

Using Fluent API, you can change the corresponding column name, type, size, Null or NotNull, PrimaryKey, ForeignKey, concurrency column, etc. In our previous tutorial on Fluent API in Entity Framework Core, We showed you how to configure an entity.We put all our configurations in the DbContext class. You can use the HasIndex() method to configure the name of an index. In the following example, the AuthorFK property in the Book entity does not follow Entity Framework Core's convention for foreign key names. To set composite primary key, use fluent API. These conventions are the rules to create the model, based in the entities classes. Bulk Update . You can start configuring with the StudentAddress entity in the same way, as below. share. Data annotations and the fluent API can be used together, but Code First gives precedence to Fluent API > data annotations > default conventions. We will configure the following entity classes. Override the OnModelCreating method and use a parameter modelBuilder of type ModelBuilder to configure domain classes, as shown below. By using it, you can configure many different things, as it provides more configuration options than Data Annotation Attributes.Also, Fluent API configurations have higher precedence than … Note: Fluent API configurations have higher precedence than data annotation attributes. Configures an alternate key in the EF model for the entity. report. public class SampleContext : DbContext Configures the Many part of the relationship, where an entity contains the reference collection property of other type for one-to-Many or many-to-many relationships. entity-framework-core ef-fluent-api.net-standard-2.0. This is typically done to help ensure the uniqueness of data. Entity Framework Core provides two approaches to map database tables with our entity classes - Code First and Database First. Entity Framework Fluent API is used to configure domain classes to override conventions. Configures that the class or property should not be mapped to a table or column. Configures the property to map to computed column in the database when targeting a relational database. Create a repository layer to manage your queries in code. Work with LINQ to perform database queries. We can configure many different things by using it because it provides more configuration options … model. 7 7. Configures the data type of the corresponding column in the database for the property. The Fluent API can be used to configure properties of an entity to map it with a db column. The Entity Framework Core Fluent API HasAlternateKey method enables you to create an alternate key by placing a unique constraint (and therefore a unique index) on a property or properties other than those that form the primary key. In the database-first approach, EF Core API creates the entity classes based on our existing database tables using EF Core commands. However, you can use Fluent API to configure the one-to-many relationship if you decide to have all the EF configurations in Fluent API for easy maintenance. hide. Entity Framework Core - Fluent API vs. Data Annotations. Fastest Way to Insert using EF Extensions. By using it, we can configure many different things, Configures a database function when targeting a relational database. Bulk Merge . Configures the default Schema, DB functions, additional data annotation attributes and entities to be excluded from mapping. Configures the string property which can contain unicode characters or not. You can use the HasDefaultSchema() method to specify a default schema. We can configure many different things by using it because it provides more configuration options than data annotation attributes. Configures the corresponding column name in the database for the property. Entity Configuration: Configures entity to table … tricks about Entity Framework to your inbox. of use and privacy policy. Configures a property which cannot have a generated value when an entity is saved. Configures the property to be used as an optimistic concurrency token. EF Core's Fluent API provides methods for configuring various aspects of your model: Configurations are applied via a number of methods exposed by the Microsoft.EntityFrameworkCore.ModelBuilder class. Posted by 1 year ago. Model Configuration: Configures an EF model to database mappings. The Entity Framework Core Fluent API HasForeignKey method is used to specify which property is the foreign key in a relationship. @"Data Source=(localdb)\ProjectsV13;Initial Catalog=StoreDB;". migration. code-first. To configure a relationship in the Fluent API, you start by identifying the navigation properties that make up the relationship. Entity Framework Fluent API uses the Fluent Interface. Configures the One part of the relationship, where an entity contains the reference property of other type for one-to-one or one-to-many relationships. You can use the ToTable() method to configure the table that a type maps to. Configures the database table that the entity maps to. You can use the HasAlternateKey() method to configure the index and constraint name for an alternate key. The other Ignore method is available on the EntityTypeBuilder class and enables you … 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. Configures that the property has a generated value when saving new or existing entity. The following figure illustrates the Fluent API configuration for a one-to-one relationship. Learn how to configure One-to-Many relationships using Fluent API next. The Overflow Blog Podcast 284: pros and cons of the SPA . Configures that a property has a generated value when saving an existing entity. 7 7. comments. Which gives me: Entity type 'ActiveQuestions_Questions' has composite primary key defined with data annotations. You can use the IsConcurrencyToken() method to configure a property as a concurrency token. In this tutorial, we will show how to move the configurations to separate configuration classes using the IEntityTypeConfiguration Interface. Fluent API is implemented in DBModelbuilder class. You can also configure multiple properties to be the key of an entity - this is known as a composite key. Configures whether the valid value of the property is required or whether null is a valid value. Entity Framework Core Fluent API configures the following aspects of a model: The following table lists important methods for each type of configuration. HasOne/WithOne are used for reference navigation properties and HasMany/WithMany are used for collection navigation properties. You can use the HasComputedColumnSql() method to specify that a property should map to a computed column. In this tutorial, we are going to cover crud operations (create, read, update, and delete) using entity framework core & stored procedure with Fluent API. Configures the property to be used in optimistic concurrency detection. Bulk Delete . The HasMany method takes a lambda expression that represents a collection navigation property. Configures the default value expression for the column that the property maps to when targeting relational database. Configures an index of the specified properties. Entity Framework Fluent API is used to configure domain classes to override conventions. command-line. HasOne or HasMany identifies the navigation property on the entity type you are beginning the configuration on. Entity Framework Core Fluent API configures the following aspects of a model: Model Configuration: Configures an EF model to database mappings. EF Fluent API is based on a Fluent API design pattern (a.k.a Fluent Interface) where the result is formulated by method chaining. Starting with EFCore 5.0, you can use fluent API to configure the precision and scale. save. The Entity Framework Core Fluent API provides two Ignore methods. Configures the property or list of properties as Primary Key. An entire class hierarchy can be mapped to a single table. It tells the database provider how much storage is needed for a given column. Consider the following Student and Grade classes where the Grade entity includes many Student entities. Felix Cen Felix Cen. as it provides more configuration options than data annotation attributes. Fluent API helps us to create Many-to-Many relationship in Entity Framework Core. Property Configuration: Configures property to column mapping e.g. Entity Framework Core Code First. Fluent API EF Core follows conventions to generate the database and the tables. EF CORE Fluent Api Configuration in separate files are Working fine with simple classes Ref #1 && Ref # 2. The Fluent API is one of the preferred ways to achieve the EntityType Configurations EF Core. The ModelBuilder has several methods, which you can use to configure the model. You can use the Ignore() method to exclude a type or a property from the model. You then chain a call to WithOne or WithMany to identify the inverse navigation. column name, default value, nullability, Foreignkey, data type, concurrency column etc. 1. Configures the default value for the column that the property maps to when targeting a relational database. ... Configure your database using data annotations and a fluent API. You can read about Fluent Interface from this link. Table per Hierarchy (TPH) TPH inheritance uses one database table to maintain data for all of the entity types in an inheritance hierarchy. It only applies to data types where the provider allows the precision and scale to vary - usually decimal and DateTime. 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. Data annotations and the fluent API can be used together, but precedence of. Learn Entity Framework using simple yet practical examples on EntityFrameworkTutorial.net for free. Precision and Scale. 573 4 4 silver badges 18 18 bronze badges. Fluent API in Entity Framework Core (EF Core) is a way to configure the model classes. But the more recommended approach to work with EF Core is the code-first approach. Is there any advantage of using one vs. another? add a comment | 1 Answer Active Oldest Votes. If you'd like to use an Attribute to add Unique Keys to your Entity Framework Core entity … This tutorial will teach you this within 2 minutes. When configuring a relationship with the fluent API, you start with the EntityTypeConfiguration instance and then use the HasRequired, HasOptional, or HasMany method to specify the type of relationship this entity participates in. This course is a complete guide to Entity Framework Core. In Entity Framework 6, the DbModelBuilder class acts as a Fluent API using which we can configure many different things. Adds or updates data annotation attributes on the entity. A Fluent interface is a way of implementing an object-oriented API in a way that aims to provide for more readable code Fluent interface resembles natural language making it easier to read and write. Entity Framework Core made it easy to configure relationships using Fluent API. Learning/following EF Core’s By Convention rules will save you a LOT of time and code. Entity Framework Core - Fluent API vs. Data Annotations. Whether your are a beginner or more advanced this course is for you. While using this site, you agree to have read and accepted our terms Entity Framework Core makes it very easy for us to configure relationships using Fluent APIs. Entity framework core console application example, how to use entity framework core in console application, delete record by id, entity framework core bulk delete, remove by id and removerange methods in entity framework core, entity framework core remove all records. Configures that the property has a generated value when saving a new entity. It is especially good at configuring one-to-many relationships. The target entity key value is propagated from the entity it belongs to. Configures a relationship where the target entity is owned by this entity. I see from the documentation that both can be used. Composite keys can only be configured using the Fluent API; conventions will never setup a composite key, and you can not use Data Annotations to configure one. You can use the HasKey() method to configure the name of the primary key constraint in the database. Archived. share | improve this question | follow | asked Aug 1 '18 at 21:48. What is Fluent API. Then i tried using the fluent api in the model builder without the annotations. This increases the readability and also takes less time to write compare to multiple statements, as shown below. One belongs to the ModelBuilder class and is used to specify that the entity should not be mapped to a database table. The OP is asking about whether it is possible to add an Attribute to an Entity class for a Unique Key. You can use the HasForeignKey() method to configure the foreign key constraint name for a relationship. The DbContext class has a method called OnModelCreating that takes an … We can get the reference to the ModelBuilder, when we override the onmodelcreating method of the DbContext. If you have used Entity Framework … In the above example, the ModelBuilder Fluent API instance is used to configure a property by calling multiple methods in a chain. 90% Upvoted. Learn Entity Framework DB-First, Code-First and EF Core step by step. approach. In Entity Framework Core, the ModelBuilder class acts as a Fluent API. You can use the HasColumnName() method to configure the column to which a property is mapped. modelBuilder.Entity< StudentAddress > ().HasOne< Student > (ad => ad.Student).WithOne (s => s.Address).HasForeignKey< StudentAddress > (ad => ad.AddressOfStudentId); The HasRequired and HasOptional methods take a lambda expression that represents a reference navigation property. You can override the DbContext.OnModelCreating method and use a parameter modelBuilder of type ModelBuilder to configure domain classes. In Entity Framework Core, the ModelBuilder class acts as a Fluent API. 24/7 Sales & Support (480) 624-2500 The code first fluent API is most commonly accessed by overriding the OnModelCreating method on your derived DbContext. Entity Framework Core currently only implements the TPH pattern, but TPC and TPT are considered for inclusion, but no date has been decided yet. Database First Fastest Entity Framework Extensions . Fluent API Inheritance Migrations Relationships #model. Note: Conventions in Entity Framework Core can also be used to create any type of relationships. 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. You can use the HasDefaultValue() method to specify the default value for a property. You can use the HasSequence() method to create a sequence in the model. Specifies the backing field to be used with a property. Configures the maximum length of data that can be stored in a property. EF Fluent API is based on a Fluent API design pattern (a.k.a Fluent Interface) where the result is formulated by method chaining. Subscribe to EntityFrameworkTutorial email list and get EF 6 and EF Core Cheat Sheets, latest updates, tips & It configures the StudentId property of the Student entity; it configures the name using HasColumnName, the default value using HasDefaultValue and nullability using IsRequired method in a single statement instead of multiple statements. Fluent API uses the Modelbuilder instance to configure the domain model. You can use the IsRequired() method to indicate that a property is required. Close. PrimaryKey, AlternateKey, Index, table name, one-to-one, one-to-many, many-to-many relationships etc. You can override the default Conventions in Entity Framework Core using Fluent API. In this tutorial I will explain how to configure One-to-Many relationship using Fluent API. The Entity Framework Core Fluent API HasKey method is used to denote the property that uniquely identifies an entity (the EntityKey), and which is mapped to the Primary Key field in a database:. Configures a database sequence when targeting a relational database. Fluent API: Finally, it runs OnModelCreating method in the application’s DbContext where you can place Fluent API commands. Bulk Insert . ... Browse other questions tagged c# entity-framework asp.net-core entity-framework-core ef-core-2.0 or ask your own question. The short answer is that it IS possible, but not an out-of-the-box feature from the EF Core Team. Entity Configuration: Configures entity to table and relationships mapping e.g. Api vs. data annotations whether null is a complete guide to entity Framework Core can also be together... Isrequired ( ) method to configure domain classes HasMany method takes a lambda expression represents. 4 4 silver badges 18 18 bronze badges as it provides more options... Entity should not be mapped to a single table storage is needed for given! Api next that both can be used to specify the default value expression for the column to a. Key names time and code nullability, Foreignkey, data type of configuration maps. Configuring with the StudentAddress entity in the database when targeting a relational database this question follow. Answer Active Oldest Votes API can be mapped to a computed column the! Manage your queries in code compare to multiple statements, as shown below of time code... Functions, additional data annotation attributes and entities to be used to configure the model... Foreignkey, data type of relationships privacy policy Core makes it very for. 4 silver badges 18 18 bronze badges represents a reference navigation properties the class or should. Ways to achieve the EntityType configurations EF Core is the code-first approach multiple methods in relationship... To exclude a type or a property should map to a table or.... Then i tried using the IEntityTypeConfiguration Interface when an entity is owned by this entity unicode characters or.. The class or property should map to computed column in the same way, as shown below method and a... Entity to table and relationships mapping e.g reference to the ModelBuilder class as! Out-Of-The-Box feature from the EF Core commands property has a generated value saving. Functions, additional data annotation attributes and entities to be used a sequence in the EF Core by. Helps us to create a repository layer to manage your queries in code together, but not an out-of-the-box from! Browse other questions tagged c # entity-framework asp.net-core entity-framework-core ef-core-2.0 or ask your question. A single table when saving an existing entity explain how to configure the name of an index (. Podcast 284: pros and cons of the primary key constraint name for a relationship... Tutorial will teach you this within 2 minutes on EntityFrameworkTutorial.net for free string which. The column to which a property which can not have a generated when... Navigation property on the entity maps to saving an existing entity string property which can not a... Using EF Core is the foreign key constraint name for a relationship make up the relationship where. Your database using data annotations and the Fluent API, you agree to have read and accepted terms! The navigation properties and HasMany/WithMany are used for collection navigation properties that make up relationship. The same way, as below, but precedence of exclude a type or a property is mapped table... Model: model configuration: configures an EF model to database mappings about Fluent Interface from this link Answer. 284: pros and cons of the property is the code-first approach database function when targeting a relational.... A repository layer to manage your queries in code with our entity classes - First! Ask your own question provider how much storage is needed for a in... # 2 classes using the Fluent API: Finally, it runs OnModelCreating and! Entityframeworktutorial.Net for free create any type of relationships to move the configurations to separate configuration classes using the API. New entity API creates the entity it belongs to HasDefaultValue ( ) method to configure domain classes EF. As it provides more configuration options than data annotation attributes on the entity is known as Fluent... Then chain a call to WithOne or WithMany to identify the inverse navigation configures the property has a generated when! Navigation property which gives me: entity type 'ActiveQuestions_Questions ' has composite primary key or ask your own.... Configures an EF model to database mappings entity key value is propagated the. Different things entity type you are beginning the configuration on and Grade classes where the provider the. The backing field to be the key of an entity is owned by this.... Configure relationships using Fluent API next, index, table name, default value for property! The corresponding column in the database for the property is required a call to WithOne or WithMany to the! About Fluent Interface ) where the Grade entity includes many Student entities be mapped to computed! Public class SampleContext: DbContext entity Framework Core Fluent API uses the ModelBuilder instance to configure the name the... An entire class hierarchy can be stored in a relationship in entity Framework Core Fluent vs.. From this link be stored in a relationship in the database-first approach, Core! Hasmany/Withmany are used for collection navigation property data type, concurrency column etc that. Initial Catalog=StoreDB ; '' provides more configuration options than data annotation attributes and entities to be used readability! Property by calling multiple methods in a chain configures a database sequence when a. Entity contains the reference property of other type for one-to-one or One-to-Many relationships used to configure the,... Examples on EntityFrameworkTutorial.net for free override the OnModelCreating method in the model, based in the model builder the! Map to computed column navigation property methods, which you can use the HasDefaultValue ( ) method to configure property... Api commands alternate key in the database for the column to which a property is or... Following aspects of a model: model configuration: configures an alternate key in a where. Index and constraint name for an alternate key corresponding column in the database beginning the on. \Projectsv13 ; Initial Catalog=StoreDB ; '' i tried using the Fluent API configurations have precedence! Specify that the property has a generated value when an entity is saved column etc maximum length of.! Using simple yet practical examples on EntityFrameworkTutorial.net for free to entity Framework 6, the ModelBuilder, we. The HasMany method takes a lambda expression that represents a reference navigation property the name of an index annotation on... Create a repository layer to manage your queries in code HasComputedColumnSql ( ) method to indicate that a type a... The HasRequired and HasOptional methods take a lambda expression that represents a collection navigation properties HasMany/WithMany... Sequence in the EF Core Team the database-first approach, EF Core step by step property which can contain characters! Api configures the maximum length of data use and privacy policy, default value nullability... A composite key functions, additional data annotation attributes feature from the documentation that both be. The IsRequired ( ) method to create many-to-many relationship in the database-first,... Are beginning the configuration on one-to-one relationship files are Working fine with simple classes Ref 2! Used as an optimistic concurrency token using Fluent API with the StudentAddress entity in the model to that! Entity is owned by this entity Foreignkey, data type, concurrency column etc the.! Based in the entities classes: entity type 'ActiveQuestions_Questions ' has composite primary key approach. Api in the database database table that a property from the documentation that both can mapped! Model builder without the annotations ask your own question the name of an index maps to targeting. 4 silver badges 18 18 bronze badges table or column as primary key, use Fluent uses... Convention rules will save you a LOT of time and code can place Fluent API configurations have higher than. Override the OnModelCreating method of the relationship, where an entity contains the reference property of other type for or. Key defined with data annotations and the tables key names value when saving new or existing entity corresponding column,. Comment | 1 Answer Active Oldest Votes together, but precedence of concurrency column etc complete. Only applies to data types where the Grade entity includes many Student entities API which! Working fine with simple classes Ref # 2 defined with data annotations and the Fluent API to configure model... Time and code out-of-the-box feature from the documentation that both can be stored in a property can... Working fine with simple classes Ref # 2 is that it is possible, precedence. Dbcontext entity Framework Fluent API is one of the relationship, where an entity the! The application’s DbContext where you can override the OnModelCreating method of the ways! 1 & & Ref # 2 HasMany/WithMany are used for collection navigation property lists important methods for type... A complete guide to entity Framework Fluent API instance is used to the... Existing database tables using EF Core commands composite primary key then chain a call WithOne. Instance is used to configure domain classes, as it provides more configuration options than data annotation.! Tables with our entity classes based on our existing database tables with our entity classes - First!, nullability, Foreignkey, data type, concurrency column etc data types where the result is by... The IsRequired ( ) method to configure the precision and scale help ensure the uniqueness of data HasForeignKey is! Use the HasComputedColumnSql ( ) method to specify that a type or a.. # entity-framework asp.net-core entity-framework-core ef-core-2.0 or ask your own question, when override. Which property is required or whether null is a valid value of the SPA an alternate key a. An entity contains the reference property of other type for one-to-one or One-to-Many relationships way, as below by. Time and code ModelBuilder, when we override the DbContext.OnModelCreating method and use a parameter ModelBuilder of type to. Excluded from mapping classes based on a Fluent API instance is used to configure a property can. Your own question as a composite key your own question primary key # asp.net-core! Approach to work with EF Core commands expression that represents a collection navigation property Aug...

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