Enum ColumnAnnotation 

pub enum ColumnAnnotation {
    Check(Check),
    Unique(UniqueConstraint),
    PrimaryKey(PrimaryKey),
    Index(Index),
    Default(Sql),
    InitializeAs(Sql),
}

Variants

Check(Check)

Moved to table.

Unique(UniqueConstraint)

Moved to table.

PrimaryKey(PrimaryKey)

Moved to table.

Index(Index)

Moved to table.

Default(Sql)

Column default annotation.

InitializeAs(Sql)

If column is created, then this attribute is used to prefill it, treat it as one-time, much more powerful DEFAULT value. It can be implemented as an UPDATE statement, or with SET TYPE … USING, but not as one-time DEFAULT, because it can reference other columns.

If column is updated, then it is just passed to USING expression, allowing to refernce older column value, just be careful with that. Initially this expression was only usable for new column creation, but after further consideration I decided there is no harm of allowing it for upgrades. Yes, this is a semi-imperative action, however it is pretty isolated and subtle to make it actually work.

After all, it doesn’t allow access to old schema version fields directly (except for the current field), thus not breaking isolation of a standalone schema definition.

Trait Implementations

impl Debug for ColumnAnnotation

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

Formats the value using the given formatter.