View update callback (issue with primary keys)

[bruce965]

According to the README, the Update callback is only called on tables and views with a public key.

As far as I understand, SpacetimeDB does not allow marking a column as public key on views, though.

The solution is treating the identity or id column as primary key as a convention, but only if no "primary_key" is defined in the metadata:

Godot-SpacetimeDB-SDK/godot-client/addons/SpacetimeDB/core/local_database.gd

Lines 88 to 100 in a158a6b

	# 1. Check metadata (preferred)
	if instance and instance.has_meta("primary_key"):
	var pk_field: StringName = instance.get_meta("primary_key")
	_primary_key_cache[table_name_lower] = pk_field
	return pk_field
	# 2. Convention: Check for "identity" or "id" field
	var properties = schema.get_script_property_list()
	for prop in properties:
	if prop.usage & PROPERTY_USAGE_STORAGE:
	if prop.name == &"identity" or prop.name == &"id":
	_primary_key_cache[table_name_lower] = prop.name
	return prop.name

Unfortunately, all views contain a "primary_key" metadata field with value "", therefore instance.has_meta("primary_key") is always true, and the identity/id convention is always ignored.

Godot-SpacetimeDB-SDK/godot-client/spacetime_bindings/schema/types/main_view_type.gd

Line 20 in a158a6b

set_meta('primary_key', '')

I think the issue might be on this line, I think it's supposed to be primary_key_name.length()!=0 instead:

Godot-SpacetimeDB-SDK/godot-client/addons/SpacetimeDB/codegen/codegen.gd

Line 241 in a158a6b

if table_names.size()!=0:

I know a big refactoring is in-progress, so I am not opening a PR, but I still wanted to document this issue. Let me know if you'd like me to open a PR nonetheless.

Thank you!

[xDovos]

in the v2 update, i removed that part of the code as it isn't reliable to just assume that identity or id is unique in the table.
if anything this should be solved in the schema parsing/codegen by setting the pk field with an alternative but it still won't reliably work on non table types and table types that don't have at least one unique value that can be used as alternative

[bruce965]

That makes sense. Although, as far as I understand, update notifications on views are quite important.

Perhaps it would make sense to check how they did it in the .NET SDK.

Please don't close this issue as not planned for now.

[xDovos]

the official sdk don't handle it at all atm. they are stuck on a super weird issue i don't see.
i cheat a bit by handling the views in the codgen as if they are tables. so if the view returns a table type, i have the primary key from looking up the existing table data and just copy pasting it.

[bruce965]

Ah, that's annoying.

they are stuck on a super weird issue i don't see

I might try to have a look in the future, maybe I'll have better luck.

But alright, if the official SDK does not support it I wouldn't feel too bad Godot's didn't either. Feel free to close as not planned if you think it makes sense. I will @ you if I find anything useful.