Cursor pagination

[tyt2y3]

Continue #754

Things to do:

I released the clear_order_by in sea-query 0.25

So the dependency is to upgrade sea-orm to sea-query 0.25.1

[tyt2y3]

Is there a PR for upgrading sea-query to 0.25?

[billy1624]

Is there a PR for upgrading sea-query to 0.25?

Hey @tyt2y3, check #834

[penso]

Is there any plan to have cursor in other directions? Like if we want to have created_at DESC to list most recent first?

[billy1624]

Hey @penso, thanks for asking!!

This is exactly what .last(N) method is for.

use sea_orm::{entity::*, query::*, tests_cfg::cake};

// Create a cursor that order by `cake`.`id`
let mut cursor = cake::Entity::find().cursor_by(cake::Column::Id);

// Filter paginated result by `cake`.`id` > 1 AND `cake`.`id` < 100
cursor.after(1).before(100);

// Get last 10 rows (order by `cake`.`id` DESC but rows are returned in ascending order)
for cake in cursor.last(10).all(db).await? {
    // Do something on cake: cake::Model
}

Docs: https://www.sea-ql.org/SeaORM/docs/basic-crud/select/#cursor-pagination

[penso]

Wouldn't it be easier to have:

let mut cursor = cake::Entity::find().cursor_by(cake::Column::Id, .desc)
for cake in cursor.first(10).all(db).await? {
}

so we don't need to convert/reverse the resulted array if we actually want to deliver the last ID first and in descending order?

[billy1624]

Hey @penso, I think we have add two additional method - first_desc and last_desc - to the cursor:

// Get first 10 rows (order by `cake`.`id` ASC but rows are returned in descending order)
for cake in cursor.first_desc(10).all(db).await? {
    // Do something on cake: cake::Model
}

// Get last 10 rows (order by `cake`.`id` ASC but rows are returned in descending order)
for cake in cursor.last_desc(10).all(db).await? {
    // Do something on cake: cake::Model
}

[tyt2y3]

Is there any drawback to just rev the Vec?

[billy1624]

Is there any drawback to just rev the Vec?

Good question! @penso?
Note that first_desc and last_desc are simply performing Vec:::rev under-the-hood loll

[penso]

No drawback than I can think of, except the mental thinking. I've done a "manual" cursor this week-end and will try to move to cursor_by and see if it's easier or not.

[billy1624]

Please! And let us know your experience after using it :)