I have the relationship of two classes.
class ClassA {
[Required]
int Id { get; set; }
[Required]
public int OtherId { get; set; }
[ForeignKey("OtherId")]
public ClassB? Other{ get; set; }
}
class ClassB {
[Required]
int Id { get; set; }
public IEnumerable<ClassA> Others { get; set; } = new List<ClassA>();
}
When I insert an object of ClassA I do it like this:
await this.Context.Set<ClassA>().AddAsync(new ClassA() { OtherId = 2 } );
await this.Context.SaveChangesAsync();
This works perfectly on the live database (Azure SQL DB). When I add the class like this and fetch it from the database later on (e.g. literally after the SaveChangesAsync), I get the object, INCLUDING the object ClassA.Other.
When I run the code on an in-memory DB on the other hand, it does not work! The inserting step works, but does NOT validate if the ID (ClassA.OtherId) exists. This means, I can set the ClassA.OtherId to "12345" without any problems, even if I do not have a single entry of ClassB. If I insert a valid ClassA.OtherId it works as well, but when I fetch the object from the database, ClassA.Other is null.
Just to clarify, why I write ClassB? Other instead of ClassB Other. This is only a simplified version of the code, I tested quickly, but in our production environment, we include/exclude certain fields from certain queries for performance reasons. Therefore, it is possible that the property might be null at certain times.
>Solution :
Most In-memory Testdoubles have some flaws in that regard, instead try to use the SQlite Provider, for it behaves more like a real Database
Example for the Configuration:
public static class EfDbContextSqliteBuilderConfigurationFactory
{
internal static Action<DbContextOptionsBuilder> GetSqliteDatabaseOption()
{
const string tempDataBaseFolder = "Database";
EnsureSqliteTempDatabaseFolderExists(tempDataBaseFolder);
return c => c.UseSqlite(new SqliteConnection($"DataSource={tempDataBaseFolder}\\{Guid.NewGuid()}.db"));
}
private static void EnsureSqliteTempDatabaseFolderExists(string tempDataBaseFolder)
{
if (!Directory.Exists(tempDataBaseFolder))
{
Directory.CreateDirectory(tempDataBaseFolder);
}
}
}