Struct IcDbmsDatabase 

pub struct IcDbmsDatabase { /* private fields */ }

The main DBMS struct.

This struct serves as the entry point for interacting with the DBMS engine.

It provides methods for executing queries.

• Database::select - Execute a SELECT query.
• Database::insert - Execute an INSERT query.
• Database::update - Execute an UPDATE query.
• Database::delete - Execute a DELETE query.
• Database::commit - Commit the current transaction.
• Database::rollback - Rollback the current transaction.

The transaction field indicates whether the instance is operating within a transaction context. The Database can be instantiated for one-shot, with [Database::oneshot] operations (no transaction), or within a transaction context with [Database::from_transaction].

If a transaction is active, all operations will be part of that transaction until it is committed or rolled back.

Implementations

impl IcDbmsDatabase

pub fn oneshot(schema: impl DatabaseSchema + 'static) -> Self

Load an instance of the Database for one-shot operations (no transaction).

pub fn from_transaction( schema: impl DatabaseSchema + 'static, transaction_id: TransactionId, ) -> Self

Load an instance of the Database within a transaction context.

Trait Implementations

impl Database for IcDbmsDatabase

fn select<T>(&self, query: Query<T>) -> IcDbmsResult<Vec<T::Record>>

where T: TableSchema,

Executes a SELECT query and returns the results.

Arguments

• query - The SELECT Query to be executed.

Returns

The returned results are a vector of [table::TableRecord] matching the query.

fn insert<T>(&self, record: T::Insert) -> IcDbmsResult<()>

where T: TableSchema, T::Insert: InsertRecord<Schema = T>,

Executes an INSERT query.

Arguments

• record - The INSERT record to be executed.

fn update<T>(&self, patch: T::Update) -> IcDbmsResult<u64>

where T: TableSchema, T::Update: UpdateRecord<Schema = T>,

Executes an UPDATE query.

Arguments

• patch - The UPDATE patch to be applied.
• filter - An optional Filter to specify which records to update.

Returns

The number of rows updated.

fn delete<T>( &self, behaviour: DeleteBehavior, filter: Option<Filter>, ) -> IcDbmsResult<u64>

where T: TableSchema,

Executes a DELETE query.

Arguments

• behaviour - The DeleteBehavior to apply for foreign key constraints.
• filter - An optional Filter to specify which records to delete.

Returns

The number of rows deleted.

fn commit(&mut self) -> IcDbmsResult<()>

Commits the current transaction.

The transaction is consumed.

Any error during commit will trap the canister to ensure consistency.

fn rollback(&mut self) -> IcDbmsResult<()>

Rolls back the current transaction.

The transaction is consumed.