Struct TableRegistry 

pub struct TableRegistry { /* private fields */ }

The table registry takes care of storing the records for each table, using the [FreeSegmentsLedger] and [PageLedger] to derive exactly where to read/write.

A registry is generic over a record, which must implement Encode.

The CRUD operations provided by the table registry do NOT perform any logical checks, but just allow to read/write records from/to memory. So CRUD checks must be performed by a higher layer, prior to calling these methods.

Implementations

impl TableRegistry

pub fn load( table_pages: TableRegistryPage, mm: &impl MemoryAccess, ) -> MemoryResult<Self>

Loads the table registry from memory.

pub fn insert<E>( &mut self, record: E, mm: &mut impl MemoryAccess, ) -> MemoryResult<()>

where E: Encode,

Inserts a new record into the table registry.

NOTE: this function does NOT make any logical checks on the record being inserted.

pub fn read<'a, E, MA>(&'a self, mm: &'a MA) -> TableReader<'a, E, MA>

where E: Encode, MA: MemoryAccess,

Creates a TableReader to read records from the table registry.

Use TableReader::try_next to read records one by one.

pub fn delete( &mut self, record: impl Encode, page: Page, offset: PageOffset, mm: &mut impl MemoryAccess, ) -> MemoryResult<()>

Deletes a record at the given page and offset.

The space occupied by the record is marked as free and zeroed.

pub fn update( &mut self, new_record: impl Encode, old_record: impl Encode, old_page: Page, old_offset: PageOffset, mm: &mut impl MemoryAccess, ) -> MemoryResult<()>

Updates a record at the given page and offset.

The logic is the following:

1. If the new record has exactly the same size of the old record, overwrite it in place.
2. If the new record does not fit, delete the old record and insert the new record.