Data
A service that declares a database gets its own SQLite file, migrated at deploy, and every call to it runs as one transaction.
The database
- A program declares its database with
#[program(database = "migrations")], a directory of.sqlfiles applied in name order at deploy. - A deploy whose migrations do not begin with the ones already applied is refused. A migration that fails refuses the deploy, and the running version keeps serving.
- Tables named
_berm_*are reserved.
Statements
berm_lang::sql(statement, params) runs one statement, with params a JSON array bound to its ? placeholders. It answers {"columns": [..], "rows": [[..]], "read": n, "written": n}.
let found = berm_lang::sql("SELECT title FROM items WHERE id = ?", "[42]")?;- Every statement of one call runs in one transaction, committed when the tool returns
Ok. BEGIN,COMMITand other transaction statements are refused.- A
#[query]tool cannot write. - One statement answers at most 4 MiB.
Without a database
A program without a database keeps values by key with berm_lang::get and berm_lang::set.
Storage
Stored bytes count everything the service keeps: the database, its write-ahead log, its keyed values, its logs while they are kept, and its image and compiled code. See Plans.