EntityFramework Code First FluentAPI DefaultValue in EF6.X

EntityFramework Code First FluentAPI DefaultValue in EF6.X

In Entity Framework 6.x Code First, you can use the Fluent API to specify default values for properties. Here's how to do it:

using System.ComponentModel.DataAnnotations.Schema; using System.Data.Entity.ModelConfiguration; public class MyEntity { public int Id { get; set; } public string Name { get; set; } public bool IsEnabled { get; set; } } public class MyEntityConfiguration : EntityTypeConfiguration<MyEntity> { public MyEntityConfiguration() { // Map to table ToTable("MyEntities"); // Set default values Property(e => e.Name).IsRequired().HasMaxLength(50); Property(e => e.IsEnabled).IsRequired().HasDefaultValue(true); } }

In this example, we're creating a MyEntity class that represents an entity in the database. We're also creating a MyEntityConfiguration class that derives from EntityTypeConfiguration<MyEntity> to configure the entity with the Fluent API.

In the MyEntityConfiguration class, we're using the Property method to specify the default value for the IsEnabled property. We're using the IsRequired method to ensure that the property is required, and the HasDefaultValue method to specify the default value.

When you create a new instance of MyEntity, the IsEnabled property will have the default value of true.

Note that in order to use HasDefaultValue, you need to include the System.ComponentModel.DataAnnotations.Schema namespace.

By using the Fluent API to specify default values for properties, you can ensure that your entities have default values when they are created, and that they are consistent across your application.

Examples

  1. "Entity Framework Code First Fluent API DefaultValue Attribute"

    • Code Implementation:
      modelBuilder.Entity<YourEntity>() .Property(e => e.YourProperty) .HasColumnAnnotation("DefaultValue", "YourDefaultValue");
    • Description: Uses the HasColumnAnnotation method to set a default value for a property in Entity Framework Code First using Fluent API.

  2. "Entity Framework Code First Fluent API DefaultValue SQL Expression"

    • Code Implementation:
      modelBuilder.Entity<YourEntity>() .Property(e => e.YourProperty) .HasColumnAnnotation("DefaultValueSql", "GETDATE()");
    • Description: Sets a default value using a SQL expression for a property in Entity Framework Code First using Fluent API.

  3. "Entity Framework Code First Fluent API DefaultValue for DateTime"

    • Code Implementation:
      modelBuilder.Entity<YourEntity>() .Property(e => e.YourDateTimeProperty) .HasDefaultValue(DateTime.Now);
    • Description: Directly sets a default value for a DateTime property in Entity Framework Code First using Fluent API.

  4. "Entity Framework Code First Fluent API DefaultValue for String"

    • Code Implementation:
      modelBuilder.Entity<YourEntity>() .Property(e => e.YourStringProperty) .HasDefaultValue("YourDefaultValue");
    • Description: Sets a default value for a string property in Entity Framework Code First using Fluent API.

  5. "Entity Framework Code First Fluent API DefaultValue for Numeric Types"

    • Code Implementation:
      modelBuilder.Entity<YourEntity>() .Property(e => e.YourNumericProperty) .HasDefaultValue(42);
    • Description: Sets a default value for numeric properties (e.g., int, double) in Entity Framework Code First using Fluent API.

  6. "Entity Framework Code First Fluent API DefaultValue for Bool"

    • Code Implementation:
      modelBuilder.Entity<YourEntity>() .Property(e => e.YourBoolProperty) .HasDefaultValue(true);
    • Description: Sets a default value for a boolean property in Entity Framework Code First using Fluent API.

  7. "Entity Framework Code First Fluent API DefaultValue for Guid"

    • Code Implementation:
      modelBuilder.Entity<YourEntity>() .Property(e => e.YourGuidProperty) .HasDefaultValue(Guid.NewGuid());
    • Description: Sets a default value for a Guid property in Entity Framework Code First using Fluent API.

  8. "Entity Framework Code First Fluent API DefaultValue for Enum"

    • Code Implementation:
      modelBuilder.Entity<YourEntity>() .Property(e => e.YourEnumProperty) .HasDefaultValue(YourEnum.DefaultValue);
    • Description: Sets a default value for an enum property in Entity Framework Code First using Fluent API.

  9. "Entity Framework Code First Fluent API DefaultValue for Nullable Property"

    • Code Implementation:
      modelBuilder.Entity<YourEntity>() .Property(e => e.YourNullableProperty) .HasDefaultValueSql("YourDefaultValueExpression");
    • Description: Sets a default value for a nullable property in Entity Framework Code First using Fluent API.

  10. "Entity Framework Code First Fluent API DefaultValue for DateTimeOffset"

    • Code Implementation:
      modelBuilder.Entity<YourEntity>() .Property(e => e.YourDateTimeOffsetProperty) .HasDefaultValue(DateTimeOffset.Now);
    • Description: Sets a default value for a DateTimeOffset property in Entity Framework Code First using Fluent API.

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