Struct CompiledDefault 

pub struct CompiledDefault { /* private fields */ }

One column DEFAULT, classified and parsed.

Compilation is the only step that reads the declaration text, so a caller holding a CompiledDefault cannot parse the expression a second time.

Implementations

impl CompiledDefault

pub fn declare(column: &str, expr: &str) -> Result<Self>

Compile the DEFAULT declared on column without evaluating it.

A parse error propagates verbatim, so the DDL gate can map an unregistered function name onto SQLSTATE 42883.

A sequence accessor is parsed, never called, so declaring a column must never advance a sequence.

pub fn compile(column: &str, expr: &str) -> Result<Self>

Compile the DEFAULT declared on column for row materialization.

An expression the parser refuses raises SqlError::UnevaluableDefault rather than a parse error: DDL already refused those at declaration, so a statement reaching here found one the catalog cannot resolve.

pub fn column(&self) -> &str

The column this DEFAULT fills.

pub fn literal(&self) -> Option<&Value>

The constant this DEFAULT spells, when it is a bare literal.

A generator or a parsed expression has no value until evaluation, so it yields None. The DDL gate checks a literal against the declared column type through this, so a DEFAULT the column cannot hold is refused where it is declared.

pub fn referenced_columns(&self) -> Vec<String>

Every row column this DEFAULT reads, in first-seen order.

A column DEFAULT is evaluated with no row in scope, so a non-empty answer means the declaration can never produce a value. A generator or a literal reads no column.

pub fn is_volatile(&self) -> bool

Whether this DEFAULT produces a fresh value on every evaluation.

A plan carrying one is never admitted to the plan cache, or the cache replays one execution’s value into every later one.

pub fn evaluate(&self, catalog: &dyn SqlCatalog) -> Result<Value>

Evaluate to one value. catalog resolves nextval and currval.

Takes no expression text, so the per-row path cannot re-parse.

Trait Implementations

impl Clone for CompiledDefault

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for CompiledDefault

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

Formats the value using the given formatter.