[−][src]Struct juniper_eager_loading::HasMany
A "has many" association.
Imagine you have these models:
struct User { id: i32, } struct Car { id: i32, user_id: i32, }
For this setup we say "user has many cars" and "cars have one user". This is the inverse of a
HasOne
assocation because the foreign key is on Car
instead of User
.
This means users can own many cars, but cars can only be owned by one user.
Example
You can find a complete example of HasMany
here.
Attributes
Name | Description | Default | Example |
---|---|---|---|
foreign_key_field | The name of the foreign key field | {name of struct}_id | foreign_key_field = "user_id" |
foreign_key_optional | The foreign key type is optional | Not set | foreign_key_optional |
root_model_field | The name of the field on the associated GraphQL type that holds the database model | N/A (unless using skip ) | root_model_field = "car" |
graphql_field | The name of this field in your GraphQL schema | {name of field} | graphql_field = "country" |
predicate_method | Method used to filter child associations. This can be used if you only want to include a subset of the models | N/A (attribute is optional) | predicate_method = "a_predicate_method" |
Errors
try_unwrap
will never error. If the association wasn't loaded or wasn't found it will
return Ok(vec![])
.
Methods
impl<T> HasMany<T>
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pub fn try_unwrap(&self) -> Result<&Vec<T>, Error>
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Borrow the loaded values. If no values have been loaded it will return an empty list. It will not return an error.
Trait Implementations
impl<T> Association<T> for HasMany<T>
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fn loaded_child(&mut self, child: T)
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fn assert_loaded_otherwise_failed(&mut self)
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impl<T: Clone> Clone for HasMany<T>
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impl<T> Default for HasMany<T>
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impl<T: Eq> Eq for HasMany<T>
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impl<T: Ord> Ord for HasMany<T>
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fn cmp(&self, other: &HasMany<T>) -> Ordering
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fn max(self, other: Self) -> Self
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fn min(self, other: Self) -> Self
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fn clamp(self, min: Self, max: Self) -> Self
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impl<T: PartialEq> PartialEq<HasMany<T>> for HasMany<T>
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impl<T: PartialOrd> PartialOrd<HasMany<T>> for HasMany<T>
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fn partial_cmp(&self, other: &HasMany<T>) -> Option<Ordering>
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fn lt(&self, other: &HasMany<T>) -> bool
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fn le(&self, other: &HasMany<T>) -> bool
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fn gt(&self, other: &HasMany<T>) -> bool
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fn ge(&self, other: &HasMany<T>) -> bool
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impl<T: Debug> Debug for HasMany<T>
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impl<T> StructuralPartialEq for HasMany<T>
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impl<T> StructuralEq for HasMany<T>
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Auto Trait Implementations
impl<T> Send for HasMany<T> where
T: Send,
T: Send,
impl<T> Sync for HasMany<T> where
T: Sync,
T: Sync,
impl<T> Unpin for HasMany<T> where
T: Unpin,
T: Unpin,
impl<T> UnwindSafe for HasMany<T> where
T: UnwindSafe,
T: UnwindSafe,
impl<T> RefUnwindSafe for HasMany<T> where
T: RefUnwindSafe,
T: RefUnwindSafe,
Blanket Implementations
impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T> From<T> for T
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impl<T> ToOwned for T where
T: Clone,
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T: Clone,
type Owned = T
The resulting type after obtaining ownership.
fn to_owned(&self) -> T
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fn clone_into(&self, target: &mut T)
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impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
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impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<Q, K> Equivalent<K> for Q where
K: Borrow<Q> + ?Sized,
Q: Eq + ?Sized,
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K: Borrow<Q> + ?Sized,
Q: Eq + ?Sized,