Transactions

aragog supports transactional operations without using a specific API thanks to the new Transaction Object.

Creating a transaction

To initiate a transaction we need to use the DatabaseConnection, as the transaction will create an equivalent DatabaseAccess object: The TransactionDatabaseConnection, that can be used instead of the classic connection to use the transactional features.

Example:

#![allow(unused_variables)]
fn main() {
// We build the connection
let database_connection = DatabaseConnection::builder()
         .build().await.unwrap();
// We instantiate a new transaction
let transaction = Transaction::new(&database_connection).await.unwrap();
}

Transaction states

An ArangoDB transaction has three states:

• Running
• Committed
• Aborted

After successfully initializing a Transaction Object, a Running transaction is created. We can now use its connection:

Example:

#![allow(unused_variables)]
fn main() {
let database_connection = DatabaseConnection::builder()
         .build().await.unwrap();
// Instantiate a new transaction
let transaction = Transaction::new(&database_connection).await.unwrap();
// Retrieve the connection
let transaction_connection = transaction.database_connection();
// We use the transaction connection instead of the classic connection
DatabaseRecord::create(
    Dish {
        name: "Pizza".to_string(),
        price: 10,
    },
    transaction_connection
).await.unwrap();
// We commit the transaction
transaction.commit().await.unwrap();
}

The create operations is using the transaction, meaning it won't be written in ArangoDB until the transaction is committed. The operation will simply be cancelled if the transaction is aborted.

Make sure to always commit or abort a transaction !