Module capabilities 

Backend capability model.

Backends declare what they support; the query layer checks a plan against these declarations before execution so unsupported features fail with a BackendCapabilityError instead of being silently ignored.

Structs

BackendCapabilities

Declared capabilities of a backend.

Enums

BackendKind

Family of a backend. Used for diagnostics and dialect selection.

Feature

A single optional query feature that a plan may require.

IsolationLevel

Transaction isolation level. Backends list the levels they honour in BackendCapabilities::isolation_levels; requesting another one is a capability error, never a silent downgrade.

RowLocking

Row-locking support level (SELECT ... FOR UPDATE).

TransactionSupport

Transaction support level.