private static async Task DeleteOrphansSampleAsync(DeleteBehavior deleteBehavior, bool requiredRelationship)
{
Console.WriteLine($"Test deleting orphans with DeleteBehavior.{deleteBehavior} and {(requiredRelationship ? "a required" : "an optional")} relationship:");
await InitializeDatabaseAsync(requiredRelationship);
await using var context = new BloggingContext(deleteBehavior, requiredRelationship);
#region DeleteOrphansVariations
var blog = await context.Blogs.Include(b => b.Posts).FirstAsync();
var posts = await blog.Posts.AsQueryable().ToListAsync();
DumpEntities(" After loading entities:", context, blog, posts);
blog.Posts.Clear();
DumpEntities(" After making posts orphans:", context, blog, posts);
try
{
Console.WriteLine();
Console.WriteLine(" Saving changes:");
await context.SaveChangesAsync();
DumpSql();
DumpEntities(" After SaveChanges:", context, blog, posts);
}
catch (Exception e)
{
DumpSql();
Console.WriteLine();
Console.WriteLine($" SaveChanges threw {e.GetType().Name}: {(e is DbUpdateException ? e.InnerException.Message : e.Message)}");
}
#endregion
Console.WriteLine();
}
private static async Task InitializeDatabaseAsync(bool requiredRelationship)
{
await using var context = new BloggingContext(DeleteBehavior.ClientSetNull, requiredRelationship);
await context.Database.EnsureDeletedAsync();
await context.Database.EnsureCreatedAsync();
context.Blogs.Add(new Blog
{
Url = "http://sample.com",
Posts = new List <Post>
{
new Post {
Title = "Saving Data with EF"
},
new Post {
Title = "Cascade Delete with EF"
}
}
});
await context.SaveChangesAsync();
}
