How to store JSON in an object field using EF Core?

Question

I am creating a reusable library using .NET Core (targeting .NETStandard 1.4) and I am using Entity Framework Core (and new to both). I have an entity class that looks like this:

public class Campaign
{
    [Key]
    public Guid Id { get; set; }

    [Required]
    [MaxLength(50)]
    public string Name { get; set; }

    public JObject ExtendedData { get; set; }
}

and I have a DbContext class that defines a DbSet:

public DbSet<Campaign> Campaigns { get; set; }

(I also use the repository pattern with DI, but I don't think that matters.)

My unit tests give me this error:

System.InvalidOperationException: it is not possible to determine the relationship represented by the navigation property "JToken.Parent" of type 'JContainer. Either manually configure the connection, or ignore this property from the model.

Is there a way to indicate that this is not a relationship, but should be stored as a large string?

Answer 1

@ , -. , "Backing Field". ExtendedData JObject : get:

public class Campaign
{
    // https://docs.microsoft.com/en-us/ef/core/modeling/backing-field
    private string _extendedData;

    [Key]
    public Guid Id { get; set; }

    [Required]
    [MaxLength(50)]
    public string Name { get; set; }

    [NotMapped]
    public JObject ExtendedData
    {
        get
        {
            return JsonConvert.DeserializeObject<JObject>(string.IsNullOrEmpty(_extendedData) ? "{}" : _extendedData);
        }
        set
        {
            _extendedData = value.ToString();
        }
    }
}

_extendedData , :

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<Campaign>()
        .Property<string>("ExtendedDataStr")
        .HasField("_extendedData");
}

: EF ( EF Core 2.1 - ), , .

Answer 2

-.

, . [NotMapped] [NotMapped] [NotMapped] .

- , . .

EF Core HasConversion() EntityTypeBuilder JSON.

2 :

public class Person
{
    public int Id { get; set; }

    [Required]
    [MaxLength(50)]
    public string FirstName { get; set; }

    [Required]
    [MaxLength(50)]
    public string LastName { get; set; }

    [Required]
    public DateTime DateOfBirth { get; set; }

    public IList<Address> Addresses { get; set; }      
}

public class Address
{
    public string Type { get; set; }
    public string Company { get; set; }
    public string Number { get; set; }
    public string Street { get; set; }
    public string City { get; set; }
}

, , , ; IE [Key].

DbContext IEntityTypeConfiguration Person:

public class PersonsConfiguration : IEntityTypeConfiguration<Person>
{
    public void Configure(EntityTypeBuilder<Person> builder)
    {
        // This Converter will perform the conversion to and from Json to the desired type
        builder.Property(e => e.Addresses).HasConversion(
            v => JsonConvert.SerializeObject(v, new JsonSerializerSettings { NullValueHandling = NullValueHandling.Ignore }),
            v => JsonConvert.DeserializeObject<IList<Address>>(v, new JsonSerializerSettings { NullValueHandling = NullValueHandling.Ignore }));
    }
}

. .

Answer 3

- ?

    [NotMapped]
    private JObject extraData;

    [NotMapped]
    public JObject ExtraData
    {
        get { return extraData; }
        set { extraData = value; }
    }

    [Column("ExtraData")]
    public string ExtraDataStr
    {
        get
        {
            return this.extraData.ToString();
        }
        set
        {
            this.extraData = JsonConvert.DeserializeObject<JObject>(value);
        }
    }

:

ExtraData = table.Column<string>(nullable: true),

Answer 4

, EF 2.1, Nufet EfCoreJsonValueConverter, .

using Innofactor.EfCoreJsonValueConverter;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata.Builders;

public class Campaign
{
    [Key]
    public Guid Id { get; set; }

    [Required]
    [MaxLength(50)]
    public string Name { get; set; }

    public JObject ExtendedData { get; set; }
}

public class CampaignConfiguration : IEntityTypeConfiguration<Campaign> 
{
    public void Configure(EntityTypeBuilder<Campaign> builder) 
    {
        builder
            .Property(application => application.ExtendedData)
            .HasJsonValueConversion();
    }
}

Answer 5

@Métoule:

: EF Core , . , person.Addresses.Add, ; person.Addresses = updatedAddresses.

, : Getter Setter, .

public void SetExtendedData(JObject extendedData) {
    ExtendedData = JsonConvert.SerializeObject(extendedData);
    _deserializedExtendedData = extendedData;
}

//just to prevent deserializing more than once unnecessarily
private JObject _deserializedExtendedData;

public JObject GetExtendedData() {
    if (_extendedData != null) return _deserializedExtendedData;
    _deserializedExtendedData = string.IsNullOrEmpty(ExtendedData) ? null : JsonConvert.DeserializeObject<JObject>(ExtendedData);
    return _deserializedExtendedData;
}

:

campaign.GetExtendedData().Add(something);

, , , ™.

- EF, partial, , .