Enum LogicalStorageNamespace 

pub enum LogicalStorageNamespace {
    UserData = 0,
    RowIdShadow = 1,
    TxnCreatedBy = 2,
    TxnDeletedBy = 3,
    Reserved = 65_535,
}

Category of data a column contains.

The LogicalStorageNamespace enum prevents ID collisions by segregating different types of columns into distinct namespaces. Each namespace can contain up to 2^16 tables, and each table can have up to 2^32 fields.

Usage

Namespaces are embedded in LogicalFieldId to create globally unique column identifiers. User code typically works with UserData columns, while system components use the other namespaces for internal bookkeeping.

Variants

UserData = 0

User-defined table columns.

This is the default namespace for regular table columns. When a table is created with columns like name TEXT, age INT, those columns use the UserData namespace.

RowIdShadow = 1

Internal shadow column tracking row IDs.

For each user column, the storage engine maintains a corresponding shadow column that stores the row ID for each value. This enables efficient row-level operations and join/filter optimizations.

TxnCreatedBy = 2

MVCC metadata: transaction that created each row.

Stores the transaction ID (TxnId) that inserted each row. Used for snapshot isolation to determine row visibility.

TxnDeletedBy = 3

MVCC metadata: transaction that deleted each row.

Stores the transaction ID that deleted each row, or TXN_ID_NONE if the row is not deleted. Used for snapshot isolation and garbage collection.

Reserved = 65_535

Reserved for future system use.

The value 0xFFFF is reserved as a sentinel to allow future expansion without breaking compatibility.

Trait Implementations

impl CheckDiscriminantInRange<BitCount<Reserved>> for LogicalStorageNamespace

type CheckType = BitCount<Reserved>

impl CheckDiscriminantInRange<BitCount<RowIdShadow>> for LogicalStorageNamespace

type CheckType = BitCount<RowIdShadow>

impl CheckDiscriminantInRange<BitCount<TxnCreatedBy>> for LogicalStorageNamespace

type CheckType = BitCount<TxnCreatedBy>

impl CheckDiscriminantInRange<BitCount<TxnDeletedBy>> for LogicalStorageNamespace

type CheckType = BitCount<TxnDeletedBy>

impl CheckDiscriminantInRange<BitCount<UserData>> for LogicalStorageNamespace

type CheckType = BitCount<UserData>

impl Clone for LogicalStorageNamespace

fn clone(&self) -> LogicalStorageNamespace

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for LogicalStorageNamespace

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

Formats the value using the given formatter.

impl PartialEq for LogicalStorageNamespace

fn eq(&self, other: &LogicalStorageNamespace) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Specifier for LogicalStorageNamespace

const BITS: usize = 16usize

The number of bits used by the Specifier.

type Bytes = <BitCount<16> as SpecifierBytes>::Bytes

The storage type. This is typically the smallest integer primitive that can store all possible values of the InOut type.

type InOut = LogicalStorageNamespace

The interface type. This type is used by getters and setters. For integers, this is the same as the Bytes type; for other types with more logical representations, like an enum or struct, this is the enum or struct.

fn into_bytes( input: <Self as Specifier>::InOut, ) -> Result<<Self as Specifier>::Bytes, OutOfBounds>

Converts an interface type into its storage type.

fn from_bytes( bytes: <Self as Specifier>::Bytes, ) -> Result<<Self as Specifier>::InOut, InvalidBitPattern<<Self as Specifier>::Bytes>>

Converts a storage type into its interface type.

impl Copy for LogicalStorageNamespace

impl Eq for LogicalStorageNamespace

impl StructuralPartialEq for LogicalStorageNamespace