here is a simplified example of how you might implement CRUD (create, read, update, delete) operations in Rust:

rust crud example with hashmap

use std::collections::HashMap;

struct DataStore {
    store: HashMap<String, String>,
}

impl DataStore {
    fn new() -> DataStore {
        DataStore { store: HashMap::new() }
    }

    fn create(&mut self, key: String, value: String) {
        self.store.insert(key, value);
    }

    fn read(&self, key: &str) -> Option<&String> {
        self.store.get(key)
    }

    fn update(&mut self, key: String, value: String) {
        self.store.insert(key, value);
    }

    fn delete(&mut self, key: &str) {
        self.store.remove(key);
    }
}

fn main() {
    let mut data_store = DataStore::new();

    // Create a new entry
    data_store.create(String::from("key"), String::from("value"));

    // Read an entry
    let value = data_store.read("key");
    println!("{:?}", value);

    // Update an entry
    data_store.update(String::from("key"), String::from("new value"));

    // Delete an entry
    data_store.delete("key");
}

This example uses a HashMap to store the key-value pairs in the DataStore struct. The create, read, update, and delete methods provide the necessary functionality for implementing CRUD operations.