deleting_at_most_one_document.md

Deleting At Most One Document

Similar to find_one and update_one, we have delete_one, which deletes at most one selected document.

collection.delete_one(doc! {"Category": "Blue box"}).unwrap();

The example above selects documents with entry "Category": "Blue box" and deletes the first selected document.

The complete code is shown below:

use polodb_core::{bson::doc, Database};

fn main() {
    let db = Database::open_memory().unwrap();
    let collection = db.collection("name_of_the_collection");

    let docs = [
        doc! {
            "Category": "Blue box",
            "Price": 1,
        },
        doc! {
            "Category": "Blue box",
            "Price": 2,
        },
        doc! {
            "Category": "Yellow box",
            "Price": 3,
        },
    ];
    collection.insert_many(docs).unwrap();

    let result = collection
        .delete_one(doc! {"Category": "Blue box"})
        .unwrap();
    println!("{:?}", result);
    
    let docs_found = collection.find(None).unwrap();
    for doc in docs_found {
        println!("{:#?}", doc.unwrap());
    }
}

Output:

DeleteResult { deleted_count: 1 }
Document({
    "Category": String(
        "Blue box",
    ),
    "Price": Int32(
        2,
    ),
    "_id": ObjectId(
        "66e3fb3c82994f4cca2de956",
    ),
})
Document({
    "Category": String(
        "Yellow box",
    ),
    "Price": Int32(
        3,
    ),
    "_id": ObjectId(
        "66e3fb3c82994f4cca2de957",
    ),
})

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