How to get the Schema of a Model in a DbContext made in the Entity Framework Core

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How to get the Schema of a Model in a DbContext made in the Entity Framework Core

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#1 by (1 votes)

1

Hello, I'm starting to work with EFCore and I'm doing an Override in the SaveChanges() method so that whenever there is a manipulation of the database I can log it. My problem is that I'm working with Schemas in my bank and I do not know how to capture the same as a EntityEntry . My code looks like this:

public partial class MyContext : DbContext
{
    // construtores...
    // models
    // ...

    public int SaveChanges(int userId)
    {
        var snapshots = ChangeTracker.Entries().ToList();
        var now = DateTime.UtcNow;

        foreach (var s in snapshots)
        {
            var entityName = s.Entity.GetType().Name;
            var schemaName = ""; // como pego isso aqui ?
            var primaryKey = getKey(s);
            var actionName = s.State.ToString();

            var obj = new Dictionary<string, string>();

            var props = s.OriginalValues.Properties
                                        .Select(x=> x.Name).ToList();

            foreach (var prop in props)
            {
                var originalValue = s.OriginalValues[prop].ToString();
                var currentValue = s.CurrentValues[prop].ToString();

                if (originalValue != currentValue)
                    obj.Add(prop, currentValue.ToString());
            }

            Log log = new Log()
            {
                Acao = $"({actionName}) {schemaName}.{entityName}",
                Registro = JsonConvert.SerializeObject(obj)
            };

            Log.Add(log);

        }

        return base.SaveChanges();
    }

    public override int SaveChanges()
    {
        return SaveChanges(0);
    }

    public virtual int getKey(EntityEntry entity)
    {
        var keyName = Model.FindEntityType(entity.GetType())
                           .FindPrimaryKey().Properties
                           .Select(x => x.Name).Single();

        return (int)entity.GetType().GetProperty(keyName).GetValue(entity, null);
    }

All my models are structured as in the example below:

[Table("Foo", Schema = "Bar")]
public partial class Foo
{
    // ...
}

How do I know which Entity Schema I am working on?

c# entity-framework-core

asked by anonymous 12.06.2018 / 13:48

1 answer

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score 1 · Accepted Answer

You have these two ways, one referring to the instance of one class and the other to the type of class:

Example:

[Table("Login", Schema = "dbo")]
public class Login
{
    [Key]       
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int Id { get; set; }

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

    [Required]
    [MaxLength(150)]
    public string Email { get; set; }
}

By instance :

Login lg = new Login();
TableAttribute tableAttribute  = (TableAttribute)lg.GetType()                   
    .GetCustomAttributes(typeof(TableAttribute))
    .FirstOrDefault();
tableAttribute.

By type of a class :

TableAttribute tableAttribute = (TableAttribute)typeof(Login)
     .GetCustomAttributes(typeof(TableAttribute))
    .FirstOrDefault();

Note: Use both namespace :

using System.ComponentModel.DataAnnotations.Schema;
using System.Reflection;

After reflection:

tableAttribute.Schema
tableAttribute.Name

References

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