Enum Hook 

#[non_exhaustive]
pub enum Hook<T: TableSource> {
    BeforeSelect(SelectFn<T>),
    BeforeInsert(Phase, BeforeFn<T>),
    BeforeUpdate(Phase, BeforeFn<T>),
    BeforeSave(Phase, BeforeFn<T>),
    BeforeDelete(BeforeDeleteFn<T>),
    AfterInsert(AfterFn<T>),
    AfterUpdate(AfterFn<T>),
    AfterSave(AfterFn<T>),
    AfterDelete(AfterFn<T>),
    BeforeDeleteAll(DeleteAllFn<T>),
    AfterDeleteAll(DeleteAllFn<T>),
}

A lifecycle hook attached to a table via Table::with_hook. Each variant carries a closure receiving exactly the references available at that stage. BeforeSave/AfterSave are sugar that register for both insert and update.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

BeforeSelect(SelectFn<T>)

Before every read that returns rows or facts about rows: list, get, get-some, streams (before the first item), count and the aggregates (sum/max/min). An Err refuses the read. Vista shells that read the source directly call Table::check_read first.

It does not run when the table is embedded in another query — related_in_condition, column_table_values_expr, get_*_query and get_expr_* build expressions or subqueries, not reads of this table. Rules that must hold inside a subquery belong in the table’s conditions, added when it is built.

Reads a write makes run it too, so a refusing BeforeSelect also refuses: an update when before- or after-update hooks exist (the stored row is read first), a delete when delete hooks exist (the row is read for them), and a write whose backend reads the row back. A Dio serves reads from its cache, filled by its own loader, so reads through a Dio don’t run the master table’s BeforeSelect.

BeforeInsert(Phase, BeforeFn<T>)

BeforeUpdate(Phase, BeforeFn<T>)

BeforeSave(Phase, BeforeFn<T>)

BeforeDelete(BeforeDeleteFn<T>)

AfterInsert(AfterFn<T>)

AfterUpdate(AfterFn<T>)

AfterSave(AfterFn<T>)

AfterDelete(AfterFn<T>)

BeforeDeleteAll(DeleteAllFn<T>)

Before delete_all, once for the whole set; per-row delete hooks don’t run.

AfterDeleteAll(DeleteAllFn<T>)