ApplyOneToOne

Configures a one-to-one relationship where TEntity is the principal entity and TDependent is the dependent entity. The method starts from the principal entity, uses the provided reference navigation, configures the dependent foreign key, applies delete behavior, and optionally sets a principal key.

Use this method when the principal entity has a single dependent reference and the dependent entity owns the foreign key. For relationship shapes with custom inverse navigations or additional constraints, use EF Core's fluent API directly.

Usage

using Microsoft.EntityFrameworkCore;
using AlmightyShogun.EntityFrameworkCore.Utils;

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.ApplyOneToOne<User, UserProfile>(
        user => user.Profile,
        profile => profile.UserId,
        isRequired: true,
        deleteBehavior: DeleteBehavior.Cascade
    );
}

Parameters

navigation: Expression<Func<TEntity, TDependent?>>
Reference navigation on the principal entity pointing to the dependent entity.

foreignKey: Expression<Func<TDependent, object?>>
Foreign key property on the dependent entity.

principalKey: Expression<Func<TEntity, object?>>?
Optional principal key property. When omitted, EF Core uses the principal primary key.
Default: null

isRequired: bool
Whether the dependent relationship is required.
Default: true

deleteBehavior: DeleteBehavior
Delete behavior applied to the relationship.
Default: DeleteBehavior.ClientSetNull

Type signature

public void ApplyOneToOne<TEntity, TDependent>(
    Expression<Func<TEntity, TDependent?>> navigation,
    Expression<Func<TDependent, object?>> foreignKey,
    Expression<Func<TEntity, object?>>? principalKey = null,
    bool isRequired = true,
    DeleteBehavior deleteBehavior = DeleteBehavior.ClientSetNull
) where TEntity : class where TDependent : class;