Complex mapping Entity Framework

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Complex mapping Entity Framework

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#1 by (2 votes)

3

I'm creating a class structure that looks like the following:

Department -Service

One department provides various types of service. A specific service can only be provided by one department, not by many.

A department can request services from others, and this is previously mapped out: Department A can request the B service (B that belongs to department C).

My problem starts there, because I have to say that a Department can request one or more services from others. I tried some ways, including putting two attributes of type " Service " in the Department class (two collections), but when Entity generates the database the table structure becomes a zone, with the Services table with two fields relating to Department .

Thinking relationally, I would have a third table with Department and Service id forming a composite key.

How can I map to classes (without generating a zone in the database)?

Thank you!

.net entity-framework

asked by anonymous 26.06.2015 / 00:26

1 answer

How to make every request be directed to a subfolder? (HTACCESS) Sorting list

score 2 · Accepted Answer

The department providing a service is one thing. One department taking one service is another. You are treating two different things as one. For your explanation, what we have is:

public class Departamento 
{
    [Key]
    public int DepartamentoId { get; set; }

    ...
    public virtual ICollection<Servico> Servicos { get; set; }
}

public class Servico 
{
    [Key]
    public int ServicoId { get; set; }
    public int DepartamentoId { get; set; }

    ...
    public virtual Departamento Departamento { get; set; }
}

If one department is requesting a service from another, I believe there should be a separate Model for this. For example:

public class RequisicaoServico
{
    [Key]
    public int RequisicaoServicoId { get; set; }
    [Index("IUQ_RequisicaoServico_ServicoId_DepartamentoId", IsUnique = true, Order = 1)]
    public int ServicoId { get; set; }
    [Index("IUQ_RequisicaoServico_ServicoId_DepartamentoId", IsUnique = true, Order = 2)]
    public int DepartamentoId { get; set; }

    [Required]
    public DateTime DataRequisicao { get; set; }
    [Required]
    public Boolean Finalizado { get; set; }
    [DataType(DataType.MultilineText)]
    [Required]
    public String Descricao { get; set; }

    public virtual Departamento Departamento { get; set; }
    public virtual Servico Servico { get; set; }
}

[Index] , introduced in this form from the Entity Framework 6.1.0, guarantees the uniqueness of the associative register. Additional validations may be required in the application to avoid extraneous errors of key duplication for the user.

Being the associative table, the only thing you would need to do now is to update the Models of Departamento and Servico to admit to be related to RequisicaoServico , ie: p>

public class Departamento 
{
    [Key]
    public int DepartamentoId { get; set; }

    ...
    public virtual ICollection<Servico> Servicos { get; set; }
    public virtual ICollection<RequisicaoServico> RequisicoesServicos { get; set; }
}

public class Servico 
{
    [Key]
    public int ServicoId { get; set; }
    public int DepartamentoId { get; set; }

    ...
    public virtual Departamento Departamento { get; set; }
    public virtual ICollection<RequisicaoServico> RequisicoesServicos { get; set; }
}