Include

NOTE: when using include your data is read only

Fetch Models and their related objects. Models are wired up to their related objects for ease of access.

Sometimes it's not the data that's important its the relationship. A good example of this is a select with opgroup.

In the following Html snippit, we want both the Food model and the FoodCategory model. We need to iterate over FoodCategory and find the relevant Food model.

In this example If we load our data with include, welds will automatically wire this up.

<label for="hr-select">Your favorite food</label> <br />

<select name="foods" id="hr-select">
  <option value="">Choose a food</option>
  <hr />
  <optgroup label="Fruit">
    <option value="apple">Apples</option>
    <option value="banana">Bananas</option>
    <option value="cherry">Cherries</option>
    <option value="damson">Damsons</option>
  </optgroup>
  <hr />
  <optgroup label="Vegetables">
    <option value="artichoke">Artichokes</option>
    <option value="broccoli">Broccoli</option>
    <option value="cabbage">Cabbages</option>
  </optgroup>
  <hr />
  <optgroup label="Meat">
    <option value="beef">Beef</option>
    <option value="chicken">Chicken</option>
    <option value="pork">Pork</option>
  </optgroup>
  <hr />
  <optgroup label="Fish">
    <option value="cod">Cod</option>
    <option value="haddock">Haddock</option>
    <option value="salmon">Salmon</option>
    <option value="turbot">Turbot</option>
  </optgroup>
</select>

Loading the data

Let us assume we have the two models Food and FoodCategory. While you could select either model with the include and make it work, we are iterating over FoodCategory first. Because of this, it is a better model to start with.

#![allow(unused)]
fn main() {
    use welds::dataset::DataSet;

    let set: DataSet<FoodCategory> = FoodCategory::all()
        .include(|c| c.food)
        .run(client.as_ref())
        .await?;
}

This leads into the next question. What is a DataSet and how do I use it?

DataSet<T>

Dataset is an iterate-able data collection like Vec. It exists to maintain and access the related data between the models.

When you access a model from it, you get your model with a little extra. The accessed data is wrapped in a special accessor struct that knows how to lookup its related objects.

#![allow(unused)]
fn main() {
    use welds::dataset::DataSet;

    let set: DataSet<FoodCategory> = FoodCategory::all()
        .include(|c| c.food)
        .run(client.as_ref())
        .await?;

    for category in set.iter() {
        println!("category: {}", category.name);

        // access the food for this spisiffic category
        let food_in_category = category.get(|x| x.food);
        for food in &food_in_category {
            println!("food: {}", food.name);
        }
    }


}