Enum OnDelete 

pub enum OnDelete {
    Cascade,
    SetNull,
    Restrict,
    SetDefault,
    NoAction,
}

Defines the behavior when a referenced object is deleted in a foreign key relationship.

This enum maps to SQL ON DELETE clauses and provides type-safe foreign key behavior.

Examples

#[ormada_model(table = "posts")]
struct Post {
    #[primary_key]
    id: i32,

    // Cascade: Delete posts when author is deleted
    #[foreign_key(Author, on_delete = Cascade)]
    author_id: i32,

    // SetNull: Set category to NULL when category is deleted
    #[foreign_key(Category, on_delete = SetNull)]
    category_id: Option<i32>,  // Must be Option for SetNull
}

Variants

Cascade

Delete related objects when the referenced object is deleted.

SQL: ON DELETE CASCADE

Example

#[foreign_key(Author, on_delete = Cascade)]
author_id: i32,

When an Author is deleted, all related Posts are automatically deleted.

SetNull

Set the foreign key to NULL when the referenced object is deleted.

SQL: ON DELETE SET NULL

Important: Field must be Option<T> when using SetNull.

Example

#[foreign_key(Category, on_delete = SetNull)]
category_id: Option<i32>,  // Must be Option!

When a Category is deleted, all Posts with that category will have category_id set to NULL.

Restrict

Prevent deletion of the referenced object if any related objects exist.

SQL: ON DELETE RESTRICT

Example

#[foreign_key(Author, on_delete = Restrict)]
author_id: i32,

Attempting to delete an Author that has Posts will result in a database error.

SetDefault

Set the foreign key to its default value when the referenced object is deleted.

SQL: ON DELETE SET DEFAULT

Example

#[foreign_key(Status, on_delete = SetDefault, default = 1)]
status_id: i32,

When a Status is deleted, all related records will have status_id set to 1.

NoAction

Let the database handle the deletion behavior.

SQL: ON DELETE NO ACTION

This is similar to Restrict but the check is deferred until the end of the transaction.

Example

#[foreign_key(Author, on_delete = NoAction)]
author_id: i32,

Implementations

impl OnDelete

pub const fn to_sql(&self) -> &'static str

Convert the enum variant to its SQL string representation.

This is used during migration generation to create the appropriate SQL.

Examples

use ormada::types::OnDelete;

assert_eq!(OnDelete::Cascade.to_sql(), "CASCADE");
assert_eq!(OnDelete::SetNull.to_sql(), "SET NULL");
assert_eq!(OnDelete::Restrict.to_sql(), "RESTRICT");

pub const fn requires_nullable(&self) -> bool

Check if this OnDelete variant requires the field to be nullable.

Returns true for SetNull, false for all others.

Examples

use ormada::types::OnDelete;

assert!(OnDelete::SetNull.requires_nullable());
assert!(!OnDelete::Cascade.requires_nullable());
assert!(!OnDelete::Restrict.requires_nullable());

Trait Implementations

impl Clone for OnDelete

fn clone(&self) -> OnDelete

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for OnDelete

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

Formats the value using the given formatter.

impl Display for OnDelete

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

Formats the value using the given formatter.

impl Hash for OnDelete

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for OnDelete

fn eq(&self, other: &OnDelete) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for OnDelete

impl Eq for OnDelete

impl StructuralPartialEq for OnDelete