Merge pull request #1743 from SeaQL/find_with_linked

Find with linked (cont'd)

Cargo.toml

@@ -34,7 +34,7 @@ tracing = { version = "0.1", default-features = false, features = ["attributes",
 rust_decimal = { version = "1", default-features = false, optional = true }
 bigdecimal = { version = "0.3", default-features = false, optional = true }
 sea-orm-macros = { version = "0.12.0-rc.3", path = "sea-orm-macros", default-features = false, features = ["strum"] }
-sea-query = { version = "0.29.0-rc.2", features = ["thread-safe"] }
+sea-query = { version = "0.29.0-rc.2", features = ["thread-safe", "hashable-value"] }
 sea-query-binder = { version = "0.4.0-rc.2", default-features = false, optional = true }
 strum = { version = "0.24", default-features = false }
 serde = { version = "1.0", default-features = false }

src/executor/select.rs

@@ -4,9 +4,9 @@ use crate::{
     SelectB, SelectTwo, SelectTwoMany, Statement, StreamTrait, TryGetableMany,
 };
 use futures::{Stream, TryStreamExt};
-use sea_query::SelectStatement;
-use std::marker::PhantomData;
-use std::pin::Pin;
+use sea_query::{SelectStatement, Value};
+use std::collections::HashMap;
+use std::{hash::Hash, marker::PhantomData, pin::Pin};
 
 #[cfg(feature = "with-json")]
 use crate::JsonValue;
@@ -993,6 +993,86 @@ where
 fn consolidate_query_result<L, R>(
     rows: Vec<(L::Model, Option<R::Model>)>,
 ) -> Vec<(L::Model, Vec<R::Model>)>
+where
+    L: EntityTrait,
+    R: EntityTrait,
+{
+    // This is a strong point to consider adding a trait associated constant
+    // to PrimaryKeyTrait to indicate the arity
+    let pkcol: Vec<_> = <L::PrimaryKey as Iterable>::iter()
+        .map(|pk| pk.into_column())
+        .collect();
+    if pkcol.len() == 1 {
+        consolidate_query_result_of::<L, R, UnitPk<L>>(rows, UnitPk(pkcol[0]))
+    } else {
+        consolidate_query_result_of::<L, R, TuplePk<L>>(rows, TuplePk(pkcol))
+    }
+}
+
+trait ModelKey<E: EntityTrait> {
+    type Type: Hash + PartialEq + Eq;
+    fn get(&self, model: &E::Model) -> Self::Type;
+}
+
+// This could have been an array of [E::Column; <E::PrimaryKey as PrimaryKeyTrait>::ARITY]
+struct UnitPk<E: EntityTrait>(E::Column);
+struct TuplePk<E: EntityTrait>(Vec<E::Column>);
+
+impl<E: EntityTrait> ModelKey<E> for UnitPk<E> {
+    type Type = Value;
+    fn get(&self, model: &E::Model) -> Self::Type {
+        model.get(self.0)
+    }
+}
+
+impl<E: EntityTrait> ModelKey<E> for TuplePk<E> {
+    type Type = Vec<Value>;
+    fn get(&self, model: &E::Model) -> Self::Type {
+        let mut key = Vec::new();
+        for col in self.0.iter() {
+            key.push(model.get(*col));
+        }
+        key
+    }
+}
+
+fn consolidate_query_result_of<L, R, KEY: ModelKey<L>>(
+    mut rows: Vec<(L::Model, Option<R::Model>)>,
+    model_key: KEY,
+) -> Vec<(L::Model, Vec<R::Model>)>
+where
+    L: EntityTrait,
+    R: EntityTrait,
+{
+    let mut hashmap: HashMap<KEY::Type, Vec<R::Model>> =
+        rows.iter_mut().fold(HashMap::new(), |mut acc, row| {
+            let key = model_key.get(&row.0);
+            if let Some(value) = row.1.take() {
+                let vec: Option<&mut Vec<R::Model>> = acc.get_mut(&key);
+                if let Some(vec) = vec {
+                    vec.push(value)
+                } else {
+                    acc.insert(key, vec![value]);
+                }
+            }
+
+            acc
+        });
+
+    rows.into_iter()
+        .filter_map(|(l_model, _)| {
+            let l_pk = model_key.get(&l_model);
+            let r_models = hashmap.remove(&l_pk);
+            r_models.map(|r_models| (l_model, r_models))
+        })
+        .collect()
+}
+
+/// This is the legacy consolidate algorithm. Kept for reference
+#[allow(dead_code)]
+fn consolidate_query_result_of_ordered_rows<L, R>(
+    rows: Vec<(L::Model, Option<R::Model>)>,
+) -> Vec<(L::Model, Vec<R::Model>)>
 where
     L: EntityTrait,
     R: EntityTrait,

src/query/combine.rs

@@ -119,12 +119,16 @@ where
     F: EntityTrait,
 {
     pub(crate) fn new(query: SelectStatement) -> Self {
+        Self::new_without_prepare(query)
+            .prepare_select()
+            .prepare_order_by()
+    }
+
+    pub(crate) fn new_without_prepare(query: SelectStatement) -> Self {
         Self {
             query,
             entity: PhantomData,
         }
-        .prepare_select()
-        .prepare_order_by()
     }
 
     fn prepare_select(mut self) -> Self {

src/query/join.rs

@@ -107,6 +107,52 @@ where
         }
         select_two
     }
+
+    /// Left Join with a Linked Entity and select Entity as a `Vec`.
+    pub fn find_with_linked<L, T>(self, l: L) -> SelectTwoMany<E, T>
+    where
+        L: Linked<FromEntity = E, ToEntity = T>,
+        T: EntityTrait,
+    {
+        let mut slf = self;
+        for (i, mut rel) in l.link().into_iter().enumerate() {
+            let to_tbl = Alias::new(format!("r{i}")).into_iden();
+            let from_tbl = if i > 0 {
+                Alias::new(format!("r{}", i - 1)).into_iden()
+            } else {
+                unpack_table_ref(&rel.from_tbl)
+            };
+            let table_ref = rel.to_tbl;
+
+            let mut condition = Condition::all().add(join_tbl_on_condition(
+                SeaRc::clone(&from_tbl),
+                SeaRc::clone(&to_tbl),
+                rel.from_col,
+                rel.to_col,
+            ));
+            if let Some(f) = rel.on_condition.take() {
+                condition = condition.add(f(SeaRc::clone(&from_tbl), SeaRc::clone(&to_tbl)));
+            }
+
+            slf.query()
+                .join_as(JoinType::LeftJoin, table_ref, to_tbl, condition);
+        }
+        slf = slf.apply_alias(SelectA.as_str());
+        let mut select_two_many = SelectTwoMany::new_without_prepare(slf.query);
+        for col in <T::Column as Iterable>::iter() {
+            let alias = format!("{}{}", SelectB.as_str(), col.as_str());
+            let expr = Expr::col((
+                Alias::new(format!("r{}", l.link().len() - 1)).into_iden(),
+                col.into_iden(),
+            ));
+            select_two_many.query().expr(SelectExpr {
+                expr: col.select_as(expr),
+                alias: Some(SeaRc::new(Alias::new(alias))),
+                window: None,
+            });
+        }
+        select_two_many
+    }
 }
 
 #[cfg(test)]

tests/relational_tests.rs

@@ -2,6 +2,7 @@ pub mod common;
 
 pub use chrono::offset::Utc;
 pub use common::{bakery_chain::*, setup::*, TestContext};
+use pretty_assertions::assert_eq;
 pub use rust_decimal::prelude::*;
 pub use rust_decimal_macros::dec;
 use sea_orm::{entity::*, query::*, DbErr, DerivePartialModel, FromQueryResult};
@@ -747,6 +748,85 @@ pub async fn linked() -> Result<(), DbErr> {
         }]
     );
 
+    let select_baker_with_customer = Baker::find()
+        .find_with_linked(baker::BakedForCustomer)
+        .order_by_asc(baker::Column::Id)
+        .order_by_asc(Expr::col((Alias::new("r4"), customer::Column::Id)));
+
+    assert_eq!(
+        select_baker_with_customer
+            .build(sea_orm::DatabaseBackend::MySql)
+            .to_string(),
+        [
+            // FIXME: This might be faulty!
+            "SELECT `baker`.`id` AS `A_id`,",
+            "`baker`.`name` AS `A_name`,",
+            "`baker`.`contact_details` AS `A_contact_details`,",
+            "`baker`.`bakery_id` AS `A_bakery_id`,",
+            "`r4`.`id` AS `B_id`,",
+            "`r4`.`name` AS `B_name`,",
+            "`r4`.`notes` AS `B_notes`",
+            "FROM `baker`",
+            "LEFT JOIN `cakes_bakers` AS `r0` ON `baker`.`id` = `r0`.`baker_id`",
+            "LEFT JOIN `cake` AS `r1` ON `r0`.`cake_id` = `r1`.`id`",
+            "LEFT JOIN `lineitem` AS `r2` ON `r1`.`id` = `r2`.`cake_id`",
+            "LEFT JOIN `order` AS `r3` ON `r2`.`order_id` = `r3`.`id`",
+            "LEFT JOIN `customer` AS `r4` ON `r3`.`customer_id` = `r4`.`id`",
+            "ORDER BY `baker`.`id` ASC, `r4`.`id` ASC"
+        ]
+        .join(" ")
+    );
+
+    assert_eq!(
+        select_baker_with_customer.all(&ctx.db).await?,
+        [
+            (
+                baker::Model {
+                    id: 1,
+                    name: "Baker Bob".into(),
+                    contact_details: serde_json::json!({
+                        "mobile": "+61424000000",
+                        "home": "0395555555",
+                        "address": "12 Test St, Testville, Vic, Australia",
+                    }),
+                    bakery_id: Some(1),
+                },
+                vec![customer::Model {
+                    id: 2,
+                    name: "Kara".into(),
+                    notes: Some("Loves all cakes".into()),
+                }]
+            ),
+            (
+                baker::Model {
+                    id: 2,
+                    name: "Baker Bobby".into(),
+                    contact_details: serde_json::json!({
+                        "mobile": "+85212345678",
+                    }),
+                    bakery_id: Some(1),
+                },
+                vec![
+                    customer::Model {
+                        id: 1,
+                        name: "Kate".into(),
+                        notes: Some("Loves cheese cake".into()),
+                    },
+                    customer::Model {
+                        id: 1,
+                        name: "Kate".into(),
+                        notes: Some("Loves cheese cake".into()),
+                    },
+                    customer::Model {
+                        id: 2,
+                        name: "Kara".into(),
+                        notes: Some("Loves all cakes".into()),
+                    },
+                ]
+            ),
+        ]
+    );
+
     ctx.delete().await;
 
     Ok(())