Drop Default trait bound of PrimaryKeyTrait::ValueType

[billy1624]

• Resolve Why PrimaryKeyTrait::ValueType: Default is needed? #171
• Depends on Add FromValueTuple trait sea-query#160

[billy1624]

I'm thinking how to get rid of all these...

// This
<<Self as ActiveModelTrait>::Entity as EntityTrait>::PrimaryKey:
            PrimaryKeyValue<<Self as ActiveModelTrait>::Entity>,

// And this
<<A as ActiveModelTrait>::Entity as EntityTrait>::PrimaryKey:
            PrimaryKeyValue<<A as ActiveModelTrait>::Entity>,

[billy1624]

Got this error, somehow...

Error: Exec("error returned from database: database table is locked: metadata")

https://github.com/SeaQL/sea-orm/runs/3719025255#step:5:290

Might be related launchbadge/sqlx#326

[tyt2y3]

Thanks. It looks good generally.

Though I don't understand why we have to add a new trait PrimaryKeyValue.

I think the existing API provides sufficient info for us to implement extract_primary_key_value_from_model.

[billy1624]

Though I don't understand why we have to add a new trait PrimaryKeyValue.

I don't want to include get_primary_key_value inside PrimaryKeyTrait because this will requires changing either...

• Add type def Entity: EntityTrait
• Add generic E: EntityTrait

I think the existing API provides sufficient info for us to implement extract_primary_key_value_from_model.

I think the only way to extract either (A, B) (tuple value) or A (single value) is to impl PrimaryKeyValue inside DerivePrimayKey and counting the number of primary key columns.

[tyt2y3]

I think, since our identity is only a tuple of 1, 2 or 3,
there can be ways to accomplish this without introducing a new trait.

Iterable actually is able to tell us the arity I suppose.

[billy1624]

Something like this?

sea-orm/src/entity/base_entity.rs

Lines 242 to 257 in beb3ec6

	fn find_by_id(values: <Self::PrimaryKey as PrimaryKeyTrait>::ValueType) -> Select<Self> {
	let mut select = Self::find();
	let mut keys = Self::PrimaryKey::iter();
	for v in values.into_value_tuple() {
	if let Some(key) = keys.next() {
	let col = key.into_column();
	select = select.filter(col.eq(v));
	} else {
	panic!("primary key arity mismatch");
	}
	}
	if keys.next().is_some() {
	panic!("primary key arity mismatch");
	}
	select
	}

[tyt2y3]

Still WIP?

[billy1624]

I think, since our identity is only a tuple of 1, 2 or 3, there can be ways to accomplish this without introducing a new trait.

Iterable actually is able to tell us the arity I suppose.

Stuck on this

[tyt2y3]

Something like this?

Yes, should be.

[tyt2y3]

still stuck?

[billy1624]

Yep loll

[billy1624]

I can avoid add a new trait by putting extract_primary_key_value method in ActiveModelTrait. And implement it inside proc_macros. How is that sounds? @tyt2y3

[tyt2y3]

No we don't need that either