Transaction

Transactions ensure a group of operations either all succeed (commit) or all fail (rollback).

Using Transactions

use zero_postgres::sync::Conn;

conn.transaction(|conn, _tx| {
    conn.exec_drop("INSERT INTO users (name) VALUES ($1)", ("Alice",))?;
    conn.exec_drop("INSERT INTO users (name) VALUES ($1)", ("Bob",))?;
    Ok(())
})?;

If the closure returns Ok, the transaction is automatically committed. If the closure returns Err, the transaction is automatically rolled back.

Automatic Rollback on Error

conn.transaction(|conn, _tx| {
    conn.exec_drop("INSERT INTO users (name) VALUES ($1)", ("Alice",))?;
    // Returns error - transaction will be rolled back
    Err(Error::InvalidUsage("oops".to_string()))
})?;
// No data inserted

Explicit Commit/Rollback

Use tx.commit() or tx.rollback() for explicit control:

conn.transaction(|conn, tx| {
    conn.exec_drop("INSERT INTO users (name) VALUES ($1)", ("Alice",))?;

    if some_condition {
        tx.commit(conn)
    } else {
        tx.rollback(conn)
    }
})?;

Nested Transactions

Nested transactions are not supported. Calling transaction while already in a transaction returns Error::NestedTransaction.

Async Transactions

For async connections, use async closures:

use zero_postgres::tokio::Conn;

conn.transaction(async |conn, _tx| {
    conn.exec_drop("INSERT INTO users (name) VALUES ($1)", ("Alice",)).await?;
    Ok(())
}).await?;