MySqlParameter type conflict when using Entity Framework with Pomelo

MySqlParameter type conflict when using Entity Framework with Pomelo

By : AJ Tech
Date : November 21 2020, 04:01 AM
will be helpful for those in need Pomelo is using MySqlConnector instead of Oracle’s own package. The benefits of this are outlined on the MySqlConnector project site:
Why use MySqlConnector over Oracle’s Connector/NET?
code :

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Entity Framework 4.1 : The navigation property 'BusinessUser' declared on type 'Login' has been configured with conflict

Entity Framework 4.1 : The navigation property 'BusinessUser' declared on type 'Login' has been configured with conflict

By : justin He
Date : March 29 2020, 07:55 AM
I hope this helps you . I am having two entities , Your BusinessUser must have relation configured as:
code :
this.HasOptional(bu => bu.LoginInfo)
    .WithRequired(l => l.BusinessUser);
Entity framework Code First multiple mappings of one entity type inside of another entity type

Entity framework Code First multiple mappings of one entity type inside of another entity type

By : Engaung Zhang
Date : March 29 2020, 07:55 AM
I think the issue was by ths following , I was able to figure this out after sleeping on it. So for anyone else that runs into a similar situation here's the new code.
code :
// No change to this class
pubic class Question
    public virtual List<QuestionAnswerOption> AvailableQuestionAnswerOptions { get; set; }
    public Question RequiredPrerequisiteQuestion { get; set; }
    public virtual List<QuestionAnswerOption> AcceptablePrerequisiteQuestionAnswerOptions { get; set; }

// Added second collection of Question, PreRequisiteQuestions
public class QuestionAnswerOption
    public int Index { get;set; }
    public string Value { get;set; } // this may be 'Yes', 'No', 'Maybe', 'Don't Know', etc.
    public virtual List<Question> Questions { get; set; }
    public virtual List<Question> PreRequisiteQuestions { get; set; }

// then inside of our database context class we have the following
protected override void OnModelCreating(System.Data.Entity.DbModelBuilder modelBuilder)


    modelBuilder.Entity<Question>().HasMany(x =>
        x.AvailableQuestionAnswerOptions).WithMany(y => y.Questions)
        .Map(m =>

    // changed this to use the new PreRequisiteQuestions collection
    modelBuilder.Entity<Question>().HasMany(x =>
        x.AcceptablePrerequisiteQuestionAnswerOptions).WithMany(y => y.PreRequisiteQuestions )
        .Map(m =>
Entity Framework conflict while adding row

Entity Framework conflict while adding row

By : h0rus
Date : March 29 2020, 07:55 AM
To fix this issue Sound like you are trying to add a record with a foreign key that allready exists or trying to add a value in de identifier column while the identifier will automaticly be filled by the database.
Have you set your keys properly on both sides? Can you post the code that goes wrong?
Mapping conflict Entity Framework

Mapping conflict Entity Framework

By : user2412236
Date : March 29 2020, 07:55 AM
To fix the issue you can do Below is the fix, I removed the navigation property on the other side of the relationship using WithMany()
Add BlogId and MessageId to Message and Blog tables
code :
HasOptional(t => t.LastMessage).WithMany().HasForeignKey(d => d.MessageId);

// Relationships
HasOptional(t => t.LastMessage)
          .WithRequired(t => t.Blog)
          .Map(t => t.MapKey("LastMessageId"));
HasOptional(t => t.Blog).WithMany().HasForeignKey(d => d.BlogId);

// Relationships
 HasRequired(t => t.Blog)
            .Map(t => t.MapKey("BlogId"));
Can I use Pomelo.EntityFrameworkCore.MySql with .NET Framework 4.x?

Can I use Pomelo.EntityFrameworkCore.MySql with .NET Framework 4.x?

By : user3171440
Date : March 29 2020, 07:55 AM
wish help you to fix your issue The Pomelo/MySqlConnector solution can indeed be used with .NET Framework. As P. Kanavos says, the hard part is having to switch to EF Core. That also works with .NET Framework, but is significantly different from EF 6.x. If your use of EF is straightforward, the change should not be overly difficult. In my application, though, the design was heavily dependent on EF6 functionality that is not present in EF Core. (Specifically, chained inclusions of linked entities, including through collections.) Also, we were composing expressions that represented the queries (with inclusions) in one class, and passing those through another class into the repository. That flow doesn't work nicely with EF Core's fluent composition of queries.
In the end, we wound up moving our database to MS SQL Server instead. But for a more conventional use of Entity Framework, it is feasible to switch to EF Core + Pomelo + MySqlConnector.
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