Sort entities in foreign key dependency order - entity-framework

Question

I am working on a mechanism to seed a collection of tables via EF Core. How can I sort a DbContext's entities in order of foreign key dependencies? Since some tables have foreign keys, some tables need to be seeded before others. It seems like there would be a simple API for performing this sort, but all I have been able to find are a couple complex recursive T-SQL implementations.
I am sure there is a common solution for this type of problem that is prevalent, I just have been unable to locate it / know how to search for it.
Update:
Because EF Core doesn't seem to support Merge/Upsert/AddOrUpdate yet, I am going down the path of a database-specific (MySQL family in this case) raw SQL query. So, I have a method like below that I want to call for a collection of entities, but I need to call this method in order of the TEntityType's foreign key dependencies. Since it is a raw SQL query and not an EF API, per se, I don't think EF can auto-magically update tables in the correct dependency order (in response to #Gert's comment).
private static void InsertOnDuplicateKeyUpdate<TEntityType>(DbContext dbContext) where TEntityType : class
{
var entityType = dbContext.Model.FindEntityType(typeof(TEntityType));
var properties = GetPropertiesLessValueGeneratedTimestamps(entityType);
var columns = string.Join(", ", properties.Select(x => x.Name));
var values = CreateValues<TEntityType>(properties);
var updates = CreateUpdates(properties);
var rawSqlString = "INSERT INTO " + entityType.Relational().TableName + " (" + columns + ") VALUES " +
values + " ON DUPLICATE KEY UPDATE " + updates;
dbContext.Set<TEntityType>().FromSql(rawSqlString);
dbContext.SaveChanges();
}

Answer 1

Entity Framework Core contains all information needed to sort entity types based on foreign key dependencies. The only issue I found when using EF Core as a source of table order is that same table references will need to be handled differently - whether it might be for example allowing inserting identifiers, disabling table triggers or some other way.
To grab a list of entity types from which you can get table names, DbSet etc, use the following function:
private IList<IEntityType> GetDependentTables(IModel model)
{
var copied = new List<IEntityType>();
var tables = model.GetEntityTypes().Where(x => x.GetKeys().Any()).ToList();
while (tables.Count > 0)
{
var copiedCount = copied.Count;
for (var i = 0; i < tables.Count; i++)
{
var table = tables[i];
if (table.GetForeignKeys().All(x => copied.Contains(x.PrincipalEntityType) || x.DeclaringEntityType == x.PrincipalEntityType))
{
copied.Add(table);
tables.RemoveAt(i);
break;
}
}
if (copiedCount == copied.Count)
{
throw new InvalidOperationException("Circular foreign keys found in remaining tables: " + string.Join(",", tables.Select(x => x.Name)));
}
}
return copied.Where(x => x.BaseType == null).ToList();
}
usage:
var tableEntityTypes = GetDependentTables(myDbContext.Model);