How to know if any columns in the ActiveModel are in a Set state.

[nickb937]

At the moment, it is possible to create an UPDATE statement where the SET field is empty i.e. UPDATE table SET WHERE id=1

let row = table::Entity::find_by_id(1).one(dbh).await?.unwrap();
let mut arow: table::ActiveModel = row.into_active_model();
arow.update(dbh).await?;

I'd like to be able to at least inspect the ActiveModel to know if all columns are unmodified and therefore not call update() e.g. a method like arow.are_any_set() which could either be a Vec<table::Column> or a simple bool. Does anybody know if there is an existing way to do this?

[billy1624]

Hey @nickb937, sorry for the late reply. There is a ActiveValue::is_set method.

For example, you can check if id is set by

assert!(arow.id.is_set())

[nickb937]

The is_set() acts on the singular column, but I couldn't use this to validate that all columns in the ActiveModel were unchanged in a future-proof way. For example at time T, the Model definition might be:

struct Table {
  A: i32,
  B: i32
}

At time T1, the Model definition might be:

struct Table {
  A: i32,
  B: i32,
  C: i32
}

Consider if the Table::ActiveModel is created in function foo(), mutated in function bar() and updated to the DB in function baz()

At development time T, when baz() was initially written, it will test for A.is_set() || B.is_set().

At time T1 when the model is changed to add the column C, the developer now needs to remember this logic check in baz() and change it to A.is_set() || B.is_set() || C.is_set().

[billy1624]

Valid concern! Try this, iterate over all columns at any time.

let active_model = fruit::ActiveModel {
    id: NotSet,
    name: NotSet,
    cake_id: Set(Some(1)),
};

assert!(fruit::Column::iter().all(|col| active_model.get(col).is_set()));

[nickb937]

Ah thanks. I hadn't noticed there was a iter() on the Column.

[JonasCir]

This should be documented then, seems like a super useful one :D

[billy1624]

Where should we put it on? Do you have any thoughts? hahaa

[JonasCir]

Currently there is an Advanced Queries chapter in the docs, maybe introduce an Advanced Features chapter with a Column introspection section?

[billy1624]

Yeah, it could! Let me mark it down.
Thanks!

[JonasCir]

Sure :) Thanks for all the great work and effort!