Module vtab 

Virtual table and cursor traits (§9.3).

Virtual tables expose external data sources as SQL tables. They follow the SQLite xCreate/xConnect/xBestIndex/xFilter/xNext protocol.

These traits are open (user-implementable). Extension authors implement them to create custom virtual table modules.

Cx on I/O Methods

Methods that perform I/O accept &Cx for cancellation and deadline propagation. Lightweight accessors (eof, column, rowid) do not require &Cx since they operate on already-fetched row data.

Structs

ColumnContext

A context object passed to VirtualTableCursor::column for writing the column value.

IndexConstraint

A single constraint from the WHERE clause that the planner is considering.

IndexConstraintUsage

Per-constraint usage information set by best_index.

IndexInfo

Information exchanged between the query planner and virtual table during index selection.

IndexOrderBy

A single ORDER BY term from the query.

ShadowTablePolicy

Policy returned by a module when the core asks whether a table name is a shadow table of a virtual table instance.

TransactionalVtabState

Snapshot-backed transaction/savepoint state for mutable virtual tables.

VtabModuleMetadata

Module-level metadata that future catalog and defensive checks can consult without hard-coding FTS5-specific behavior in unrelated layers.

VtabRiskLevel

Defensive/risk metadata analogous to SQLite’s vtab safety flags.

Enums

ConstraintOp

Comparison operator for an index constraint.

ShadowTableAccess

Access decision for a shadow-table operation class.

ShadowTableKind

Classification for a schema object named by a virtual-table module.

VtabIntegrityPolicy

Integrity surface advertised by a module.

VtabLifecyclePolicy

Lifecycle shape a module exposes to the connection/catalog layer.

Traits

ErasedVtabCursor

A type-erased virtual table cursor.

ErasedVtabInstance

A type-erased virtual table instance.

VirtualTable

A virtual table module.

VirtualTableCursor

A cursor for scanning a virtual table.

VtabModuleFactory

A type-erased virtual table module factory.

Functions

module_factory_from

Create a VtabModuleFactory from a VirtualTable type.