As part of a small library I am writing, I have a Sturct "DataBase" that provides a thin wrapper around rusqlite:
pub struct DataBase {
name: String,
config_file: String,
conn: Connection,
cache: HashMap<String, CachedTable>,
batch_size: usize,
cache_size: usize,
}
impl DataBase {
pub fn new(db_name: &str, config_file_name: &str) -> Self {
let db_conn = Connection::open(db_name).unwrap();
let mut db = DataBase {
name: db_name.to_owned(),
config_file: config_file_name.to_owned(),
conn: db_conn,
cache: HashMap::new(),
batch_size: 50,
cache_size: 0,
};
db.conn
.execute_batch(
"PRAGMA journal_mode = OFF;
PRAGMA synchronous = OFF;
PRAGMA temp_store = MEMORY;
PRAGMA cache_size = 1000000;
PRAGMA locking_mode = EXCLUSIVE;",
)
.expect("PRAGMA");
db.initialize_cache().unwrap();
db
}
This works as a prototype but I need to find a way work with a rusqlite Transaction rather than the Connection. However, when one creates a Transaction with let tx = conn.transaction().unwrap();, the Connection Struct is "consumed" by the transaction method and can no longer be easily stored in a struct or passed/borrowed further on.
The one way around I can think of is to create the Connection and Transaction Structs outside my own Struct and pass a reference to the Transaction when creating a new Struct.
As I am fairly new to Rust, I have the following question: is this the only (and correct) solution to this problem or am I missing a trick?