Module defaults 

Column DEFAULT expression compilation and evaluation at insert time.

A declared DEFAULT is stored in the catalog as text. ColumnDefaults compiles that text ONCE per statement; the per-row path evaluates the compiled form and never sees a string, so it cannot re-parse.

Supported forms: ID generation functions (UUIDv4/v7, ULID, CUID2, NANOID), NOW(), sequence accessors (nextval, currval), literals, and any other expression the plan-time const-folder can resolve.

A DEFAULT that cannot be evaluated raises crate::SqlError::UnevaluableDefault. The column is never omitted: an omitted column stores NULL where the declaration promised a value, and nothing reports it.

Lives in the planner because every engine’s rows materialize their DEFAULTs there, before declared-type coercion and range checks run, so a materialized default is validated exactly like a supplied one and a DEFAULT now() means the same thing on every engine.

Structs

ColumnDefaults

Every declared DEFAULT of one collection, compiled once for a statement.

CompiledDefault

One column DEFAULT, classified and parsed.

Functions

default_value_to_sql

Convert an evaluated default back into the planner’s literal type.

validate_default_expr

Check that expr, the DEFAULT declared on column, can be evaluated.