Struct DbmsContext 

pub struct DbmsContext<M>
where
    M: MemoryProvider,
{ /* private fields */ }

Owns all mutable DBMS state behind interior-mutable wrappers.

Each component is wrapped in a RefCell so that operations borrowing different components can coexist without requiring &mut self on the context.

Threading

DbmsContext is !Send and !Sync because of the RefCell wrappers. This is intentional: WASM runtimes (both IC canisters and WASI preview 1 modules) execute single-threaded, so interior mutability via RefCell is sufficient and avoids the overhead of synchronization primitives. Embedders that need multi-threaded access should wrap the context in their own synchronization layer.

Implementations

impl<M> DbmsContext<M>

where M: MemoryProvider,

pub fn new(memory: M) -> Self

Creates a new DBMS context, initializing the memory manager and loading persisted state.

pub fn flush(&self) -> DbmsResult<()>

Publishes changes made through this context to the memory provider.

Providers without durable storage implement this as a no-op. Active transaction overlays remain uncommitted and are not flushed.

pub fn id(&self) -> ContextId

Returns the stable identity of this context.

pub fn register_table<T: TableSchema>(&self) -> DbmsResult<TableRegistryPage>

Registers a table schema, persisting it in stable memory.

pub fn has_table(&self, name: &str) -> bool

Returns whether name resolves to a registered table.

pub fn begin_transaction(&self) -> TransactionId

Begins a new transaction and returns its ID.

The engine does not record who opened the transaction: any code that holds the ID can use, commit, or roll it back. An embedder that serves several identities keeps its own ledger from ID to identity and checks it before every transactional call.

pub fn has_transaction(&self, tx_id: &TransactionId) -> bool

Returns whether tx_id names a transaction that is still open.

Embedders use it to drop ledger entries whose transaction was closed through a path they did not see.

Trait Implementations

impl<M> Debug for DbmsContext<M>

where M: MemoryProvider,

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.