118 lines
2.6 KiB
Rust
118 lines
2.6 KiB
Rust
use crate::{EntityTrait, Identity, IntoIdentity, Iterable, QuerySelect, Select};
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use core::marker::PhantomData;
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use sea_query::{DynIden, IntoIden, JoinType};
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use std::fmt::Debug;
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#[derive(Clone, Debug)]
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pub enum RelationType {
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HasOne,
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HasMany,
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}
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pub trait RelationTrait: Iterable + Debug + 'static {
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fn def(&self) -> RelationDef;
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}
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pub trait Related<R>
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where
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R: EntityTrait,
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{
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fn to() -> RelationDef;
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fn via() -> Option<RelationDef> {
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None
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}
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fn find_related() -> Select<R> {
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Select::<R>::new().join_join_rev(JoinType::InnerJoin, Self::to(), Self::via())
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}
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}
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pub struct RelationDef {
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pub rel_type: RelationType,
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pub from_tbl: DynIden,
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pub to_tbl: DynIden,
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pub from_col: Identity,
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pub to_col: Identity,
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}
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pub struct RelationBuilder<E, R>
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where
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E: EntityTrait,
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R: EntityTrait,
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{
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entities: PhantomData<(E, R)>,
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rel_type: RelationType,
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from_tbl: DynIden,
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to_tbl: DynIden,
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from_col: Option<Identity>,
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to_col: Option<Identity>,
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}
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impl RelationDef {
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/// Reverse this relation (swap from and to)
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pub fn rev(self) -> Self {
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Self {
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rel_type: self.rel_type,
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from_tbl: self.to_tbl,
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to_tbl: self.from_tbl,
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from_col: self.to_col,
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to_col: self.from_col,
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}
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}
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}
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impl<E, R> RelationBuilder<E, R>
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where
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E: EntityTrait,
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R: EntityTrait,
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{
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pub(crate) fn new(rel_type: RelationType, from: E, to: R) -> Self {
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Self {
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entities: PhantomData,
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rel_type,
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from_tbl: from.into_iden(),
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to_tbl: to.into_iden(),
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from_col: None,
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to_col: None,
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}
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}
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pub(crate) fn from_rel_def(rel: RelationDef) -> Self {
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Self {
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entities: PhantomData,
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rel_type: rel.rel_type,
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from_tbl: rel.from_tbl,
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to_tbl: rel.to_tbl,
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from_col: Some(rel.from_col),
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to_col: Some(rel.to_col),
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}
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}
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pub fn from(mut self, identifier: E::Column) -> Self {
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self.from_col = Some(identifier.into_identity());
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self
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}
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pub fn to(mut self, identifier: R::Column) -> Self {
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self.to_col = Some(identifier.into_identity());
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self
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}
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}
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impl<E, R> From<RelationBuilder<E, R>> for RelationDef
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where
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E: EntityTrait,
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R: EntityTrait,
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{
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fn from(b: RelationBuilder<E, R>) -> Self {
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RelationDef {
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rel_type: b.rel_type,
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from_tbl: b.from_tbl,
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to_tbl: b.to_tbl,
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from_col: b.from_col.unwrap(),
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to_col: b.to_col.unwrap(),
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}
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}
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}
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