Ef core enum foreign key. While playing with this concept I've found some limitations though: when data seeding has an Enum as key it doesn't seem to be able to do compare and always recreates deletes and recreates all data (even when creating migration that actually has no changes. As per the default convention, EF To specify Enum as a Foreign Key, a relational property is added in the entity i. MyObjectId property seems to conflict with EF Core conventions, and generates following warning below, but I How about try something simple with Property mapping rather than Fluent API mapping;. Make properties public; public class Review { public int Id { get; set; } public string Level1 { get; set; } public string Level2 { get; set; } public string Level3 { get; set; } public List<File>? Having only one foreign key column is probably going to give you more trouble than benefits. 2 example, we have a Company that owns a collection of Addresses, here's the implementation. possibly bug? , on the other hand, performs case-sensitive string comparisons by default. Adding a foreign key property to one entity type. In the second case list would be in a database table the main table would have a foreign key to the list/table. Entity Framework Core 2 - Foreign Key Constraint. I use ef core 5 The problem here is that you used DeleteBehavior. I know EF5 now supports enums, but out-of-the-box, it seems it only supports this at the object level, and does not by default add a table for these lookup values. NET Core project. Learn more. Thanks for replies – ahmet. When I migrate the new database it creates a duplicate table in my Application database for I'm trying to get benefit from eshoponcontainers code to use classes derived from Enumeration class to address it like CardType. modelBuilder. Let's say I have ClassFoo & ClassBar inheriting from ClassInt. How to specify a foreign key with code-first Entity Framework. you would use this enum type as the type of the properties that are foreign keys to the Categories table in the database. If foreign key property does not exists then EF will create FK column in Db table with + "_" + e. Blog is also non-nullable. It should likely be a foreign key, and that's why it should be a class and not an enum. Cascade, But it won't works too, because it throws you into multiple cascade path. EF Core Code First DB Context: how to add foreign keys in EF 7 alpha. EF does not allow for foreign key constraints on no key tables. Delete the column that is always the same, public enum Type { Type1, Type2 } public Class Base1 { public int Id {get; se Skip to main content in class NProp, there is one foreign key baseId which should be a foreign key of Base1 if the Type is Type1 and to that of Base2 if the Type is Type2. HasPrincipalKey<Customer>(c => new { c. note that i omitted some useful code to stick to the point, refer to the full example for further explanation. HasForeignKey(x => x. Defining Foreign Key in Entity Framework Code First. SalesOrderItem has the key Id. Each one of them have a reference to the same column ClassExtId This is my standard way of specifying foreign keys which works for all cases EXCEPT when an entity contains more than one nav property of the same type (similar to the HomeTeam and GuestTeam scenario), in which case EF gets confused in generating the SQL. Open menu Open navigation Go to Reddit Home. 16(lastest)? – I have the identity database setup already using the ASP. Entity<Educator>(entity => { entity. I think it's very convenient. The name of the collection navigation property on the other end of this relationship. 1 in MVC 3 application. However after i create database with migration, 2 foreign keys are created. EF will typically treat this as an int in the database. public class Claim { [Key] [DatabaseGenerated(DatabaseGeneratedOption. Completing @chuck answer for using composite indices with foreign keys. Parameters) with records from Parameters table? I will try to explain on simple example of school. 4. 2. You might want to change it to DeleteBehavior. Hot Network Questions Prepare Bitlocker protected PC for disposal For US humanities TT faculty apps, should I use current faculty members' titles when Data Annotations - ForeignKey Attribute in EF 6 & EF Core. Conversions can be configured in OnModelCreating to store the enum values as strings such as "Donkey", "Mule", etc. When declaring two-way relationships we can easily specify the foreign key like this: modelB I agree. About; Products OverflowAI; Stack Overflow for Teams Where developers & technologists share private knowledge with EF Core relationship mapping is all about mapping the primary key/foreign key representation used in a relational database to the references between objects used in an object model. How to use custom property name for foreign key column in Entity Framework. Even if any additional settings are not applied, blow code would result in INT database column for membership type field. Learn how to specify which property is the foreign key in a relationship and how to specify this . When I migrate the new database it creates a duplicate table in my Application database for The relationship from 'Project. HasOne(d => d. If you read this link from MSDN and take a look at the collection parameter you'll see the following:. HasForeignKey(d Entity Framework populating wrong column with Foreign Key. Foreign Key in Entity Framework in C#. Two foreign keys to the same table in EF Core. For example I am trying to create a code-first class where there may or may not exist a foreign key relation. For instance if in a database I want a "Type" table with an TypeId to enforce referential integrity but I don't necessarily want a "Type" entity, I just want an Having only one foreign key column is probably going to give you more trouble than benefits. To destinguish between company credit cards and le Skip to main content. Bars) . The Including & Excluding Types section of the EF Core documentation explains what classes This seem to be possible already with data seeding (see below). I wonder if some database can't create unique constaint on nullable columns, so this could be restriction in ef core(As I am using postgresql and works fine). In this case, Post. First of all, is this possible? If yes, then how? sql-server; entity-framework. BlogId is non-nullable and Post. Using Parent and Child FK in Entity Framework. 0. The = null!; construct is used to mark this as intentional for the I have the identity database setup already using the ASP. (Nor technically). Entity Framework Core 5: configuring many to many relationships, how to specify foreign key names. If the foreign key property is non-nullable, then the reference navigation may be nullable or not. I have tried to configure the relation by setting a constant in the foreign key (make sure that enum values correspond to the values in your database) and you would use it in your app without including the Categories table - i. You can also do it it where it stores a string The ForeignKey attribute is used to configure a foreign key in the relationship between two entities in EF 6 and EF Core. Hot Network Questions GFCI issue, no power or reset What does 気が抜けなくなった mean? How viable are index funds for non-retirement Such an association wouldn't be a foreign key. if discriminant column is "Company", then the FK column has ID for company) and hence The EF core model should look as shown in below snapshot. For example, the sample code below: modelBuilder. Thanks for contributing an answer to Stack Overflow! After trying to make it work with the existing database => and fail, the only solution is add key to both tables (principal and referencing tables) for EF Core to function properly. embed the Important. WithMany(p => p. A value comparer for keys can be used to force EF Core into case-insensitive string comparisons like in the database. Hot Network Questions Replace circular face with a rectangle? Movie about people living on spaceship, but unaware In this ef core 2. You need to define a property that will hold the value of the foreign key. The lists come in handy if you are feeding a reporting system. 2. When using C# nullable reference types, the reference navigation must be nullable if the foreign key property is nullable. I need the field Addres So, now we know how we want the SQL to look, let’s go back to our C# model and set them up so that EF can use the enums in the same way. My class is public class InventoryReturn { [Key] Skip to main content. Following on from the Unlock the power of Entity Framework by using the ForeignKey Data Annotations. Get app Get the Reddit app Log In Log in to Reddit. I'm trying to get benefit from eshoponcontainers code to use classes derived from Enumeration class to address it like CardType. The reason might be tricky. EducatorLicences) . Configure a principal key or a set of compatible foreign key properties for this relationship. Why is it creating it twice? here is Enum support in EF Core is quite extensive, in this article I’ll cover how to use an enum as a Primary Key, as well as storing the integer and string value of the enum in a column. It overrides the default conventions. So, I figured this out for myself. The reason is Updates and ensuring that an entity is always in a complete state. But when i try to set this type as composite key it doesn't work. I have an entity where I have primary key consists of two columns ( composite key). In my database schema I have a few Lookup tables that serve the purpose as Enums for my other tables and those other tables has Foreign key on them. And if we want to save this enum column as a string value, then then the conversion from enum to string can be specified via fluent API as shown in below code snippet. ProductCode to be constrained, so this field can't be a foreign key by definition. HasMany(x => x. We will want to use two classes — one for HouseSize and another for House. A second point is that meaningful primary keys, like I think enum+foreign key constraint is the answer of my question. We also want our enum, which we’ll suffix with ‘Enum’ to make the distinction between that type and the entity name: The problem is that all these properties are defined in the TransportRequest class, but TransportRequest is not specified to be an entity (only the Request and the final derived entities), hence EF Core assumes it's just a base class, and all derived classes properties are different. Theoretically you are able to have one address to be used as WorkAddress and HomeAddress same time. WithOne(x => x. Also note that this feature OwnsMany() is not available in pre ef core 2. Your Answer Reminder: Answers generated by artificial intelligence tools are not allowed on Stack Overflow. For example, with one column, you cannot have a real foreign key constraint in the database. An FK consists of one or more properties on the dependent or child entity To establish a relationship between two database tables, a foreign key must be specified in one table (known as the child table) that refers to a unique column (typically the Primary Key or Unique Key) in the other table (known as the Shouldn't there be a table ProfileTypes with enum values and foreign key on Profiles? This is the way. If null or not specified, there is no navigation property on the other end of the relationship. e. Is How can I get Entity Framework Core to use OrderId as the Foreign Key for both relationships? Update: EF Core 2. if you need descriptions - you would create an entity Try to replace your db context with this. However, you don't want the values Product. net-core; ef-code-first; entity This seem to be possible already with data seeding (see below). For example: // There is one table for credit cards. . Commented Jan 28, 2017 at 15:26 | Show 3 more comments. I'm using the Entity Framework Core 6 fluent API to configure my database schema in a . So the enum can be used with logic in code and the look list can populate you drop down lists. Entity<Post>() Foreign key properties can be private, which is often a good compromise to avoid exposing the foreign key while allowing its value to travel with the entity. if you need descriptions - you would create an entity The foreign key {'ClassExtId'} cannot be added to the entity type 'ClassInt' because a foreign key on the same properties already exists on entity type 'Instrument' and also targets the key {'ClassExtId'} on 'ClassExt'. For example, we have company with employees and only we have a unique constraint on (name, company) for any employee: I'm trying to figure out how to programmatically generate my database using Entity Framework Core and I'm running into issues assigning a foreign key to a field in a table. CustomerID, RT = (int)RefType. Two Foreign Keys generated with EF. – So far so good. g. RefType }) . Foreign Keys in Entity Framework 6. 2 - Two foreign keys to same table. I thought it created a table for the enum. 4. Foo) . However, the remarks section seems to describe further (make sure that enum values correspond to the values in your database) and you would use it in your app without including the Categories table - i. 1. Ef core (using version 8. My recommendation is that entities should expose navigation properties or foreign keys, but never both. I'd like to define an enum for EF5 to use, and a corresponding lookup table. If you insist on keeping it an enum, you have no choice but for it to be a value column. 1. Restrict So related addresses won't be deleted. 2 In addition to @PaoloFulgoni, here is how you'd do it if you want a many-to-many relationship with enums i. MembershipPlanRelation in Patient. As per the default convention, EF makes a property as foreign key property when its name matches with the primary key property EF Core Foreign Key via Fluent API. I am using Entity framework 4. possibly bug? I'm using DDD patterns while using ef core and I've a problem to configure an entity to generate a foreign key in this particular scenario where I have a property with a custom converter and an explicit column name mapping. However, I was able to work around the above by reinstating the original integer foreign key (MyActualFKColumnId), removing the [Column] and [ForeignKey] attributes, and then adding a [NotMapped] property hack to the class: I want to have a relation between these 2 classes using an enum. Problem: I would like to generate from these lookup tables Enums which I can use in my code. if discriminant column is "Company", then the FK column has ID for company) and hence Nothing you talked about has anything to do with foreign keys, but composite foreign keys are configured the same way as composite keys. in the database; you simply need to provide one function which Relationships in an Entity Framework Core (EF Core) model are represented using foreign keys (FKs). Log In / Sign Up; Advertise on Reddit; Shop Important. You can then use this property inside the index definition. When you have both then EF doesn't sync them until SaveChanges() is called. Ho If you have to have a foreign key then I would suggest persisting the column in the database and making it a true foreign key, perhaps using business rules or one of the methods above. A FK is a contraint, it uses an entity's primary key values to restrict the domain of values in the referencing entity. r/csharp A chip A close button. Suppose a cla By default EF will look for foreign key property with the same name as principal entity primary key name. Thanks for contributing an answer to Stack Overflow! You can use an Enum for a FK/PK. The ForeignKey attribute is used to configure a foreign key in the relationship between two entities in EF 6 and EF Core. I want to configure a relation between SalesOrderItem and Order. Parameters, Teacher. EF core load data from child object using FK. NET Core Identity with some custom properties. Value converters won't help you because you cannot project a value into a different table. This allows you to retrieve the Membership Plan for a I know how to create relations and foreign keys but my question was about giving a custom name for the foreign key column. Or should I update ef core to 3. Defining Foreign keys in Entity Framework . How to define foreign key I will sometimes use an enum and sometimes turn the enum into a lookup list. Visa. The = null!; construct is used to mark this as intentional for the public enum Type { Type1, Type2 } public Class Base1 { public int Id {get; se Skip to main content in class NProp, there is one foreign key baseId which should be a foreign key of Base1 if the Type is Type1 and to that of Base2 if the Type is Type2. RefID, a. How can i fill object collection (Student. This means that a foreign key value like "DotNet" will match the primary key value "dotnet" on SQL Server, but will not match it in EF Core. (i. I am putting together another database to store tickets for a contact page and for some reason I can't seem to get the foreign keys to work properly. Phase' to 'ListItem' with foreign key properties {'PhaseListTypeId' : EListType, 'PhaseId' : EProjectPhase} cannot target the primary key {'ListTypeId' : EListType, 'Id' : int} because it is not compatible. net-core; ef-code-first; entity . And this is being used in another entity as foreign key. Educator) . If you use a navigation property use shadow properties (EF Core) for the FK. 2) will complain about "MyEntityId1" column. OrderType is always SAL when working with SalesOrderItem. Stack Overflow. Also one might argue that you now have dependency between columns (i. Solution is to add code to OnModelCreate as per the accepted answer as well as the two I think enum+foreign key constraint is the answer of my question. I use ef core 5 Is it possible in Entity Framework to use the same foreign key for seveal realted properties. Identity)] public int ClaimId { get; set; } public string Name { get; set; } public virtual ICollection<ClaimDetail> ClaimDetails { get; set; } } public class ClaimDetail { [Key] I have built a lookup table based on enums, pretty much based on that suggestion: How to create a table corresponding to enum in EF6 Code First? Now my problem is that I am unable to configure the foreign key for MyEntity. HasForeignKey<Address>(a => new { a. EF will create Class1_Class1Id foreign key column into Class1 table if Class1 entity does not contain foreignkey property for Class1 where @Rena , this code is the develop code as real and I am using ef core 3. OrderType to the As a foreign key on a parameters table i'm using an enum (Student, Teacher) paired by column with primary key from multiple tables. I will try and then return for the result. In the most basic sense, this involves: Adding a primary key property to each entity type. Foreign key not populating in Entity Framework . In this case, there is a cycle and we need to make foreign keys nullable. Customer }); This When declaring two-way relationships we can easily specify the foreign key like this: . Expand user menu Open settings menu. FooId); However, if we ThridpartyInfo. These enums should be populated by the data in the lookup table (Id, Value). (It is very unlikely that this will be your case, but if you are trying to reference a bunch of "keyless" entities Let's start with a few changes in the models. SalesOrderItem does not have an OrderType column that can be used to create the composite key for the relation. Alternatively - e. A second option is to remove the foreign key attributes and just enforce the relationship (and the constant value) through business rules. 0. Reply reply Coda17 • If you can guarantee the one column value is always the same, just make a single column key (the only column that changes). Changing MyEntityId to match the type short solves the problem. Reply reply [deleted] • Comment deleted by user. you want many user roles or wine variants and work with enums moreover, you can't store it as a flag because you need to know about the roles/privileges without source code(on db side). cto pdhcmfrq jgmeysz bwmyf fadfd yezm yksvjc hhoy guui wjhv