Select

src/driver/sqlx_mysql.rs

@@ -1,6 +1,7 @@
 use async_trait::async_trait;
 use sqlx::{mysql::MySqlRow, MySqlPool};
 
+use sea_query::MysqlQueryBuilder;
 sea_query::sea_query_driver_mysql!();
 use sea_query_driver_mysql::bind_query;
 
@@ -12,6 +13,8 @@ pub struct SqlxMySqlExecutor {
 
 #[async_trait]
 impl Executor for SqlxMySqlExecutor {
+    type QueryBuilder = MysqlQueryBuilder;
+
     async fn query_one(&self, stmt: Statement) -> Result<QueryResult, ExecErr> {
         debug_print!("{}, {:?}", sql, values);
 

src/entity/base.rs

@@ -1,4 +1,5 @@
 use super::{Column, Identity, Relation};
+use crate::Select;
 use sea_query::Iden;
 use std::fmt::Debug;
 use strum::IntoEnumIterator;
@@ -10,11 +11,13 @@ pub trait Entity: Iden + Default + Debug {
 
     type Relation: Relation + IntoEnumIterator;
 
-    fn table_name() -> Self;
-
     fn primary_key() -> Identity;
 
     fn auto_increment() -> bool {
         true
     }
+
+    fn find<'s>() -> Select<'s, Self> {
+        Select::new(Self::default())
+    }
 }

src/entity/relation.rs

@@ -11,19 +11,19 @@ pub enum RelationType {
 }
 
 pub trait Relation {
-    fn rel_def() -> RelationDef;
+    fn rel_def(&self) -> RelationDef;
 }
 
 pub struct RelationDef {
-    rel_type: RelationType,
+    pub rel_type: RelationType,
-    from_tbl: Rc<dyn Iden>,
+    pub to_tbl: Rc<dyn Iden>,
-    from_col: Identity,
+    pub from_col: Identity,
-    to_col: Identity,
+    pub to_col: Identity,
 }
 
 pub struct RelationBuilder {
     rel_type: RelationType,
-    from_tbl: Rc<dyn Iden>,
+    to_tbl: Rc<dyn Iden>,
     from_col: Option<Identity>,
     to_col: Option<Identity>,
 }
@@ -56,7 +56,7 @@ impl RelationBuilder {
     {
         Self {
             rel_type,
-            from_tbl: entity.into_iden(),
+            to_tbl: entity.into_iden(),
             from_col: None,
             to_col: None,
         }
@@ -83,7 +83,7 @@ impl From<RelationBuilder> for RelationDef {
     fn from(b: RelationBuilder) -> Self {
         RelationDef {
             rel_type: b.rel_type,
-            from_tbl: b.from_tbl,
+            to_tbl: b.to_tbl,
             from_col: b.from_col.unwrap(),
             to_col: b.to_col.unwrap(),
         }

src/executor/mod.rs

@@ -1,6 +1,10 @@
+mod query;
+
+pub use query::*;
+
 use crate::QueryResult;
 use async_trait::async_trait;
-use sea_query::Values;
+use sea_query::{GenericBuilder, Values};
 use std::{error::Error, fmt};
 
 pub struct Statement {
@@ -10,6 +14,8 @@ pub struct Statement {
 
 #[async_trait]
 pub trait Executor {
+    type QueryBuilder: GenericBuilder;
+
     async fn query_one(&self, stmt: Statement) -> Result<QueryResult, ExecErr>;
 
     async fn query_all(&self, stmt: Statement) -> Result<Vec<QueryResult>, ExecErr>;

src/executor/query.rs

@@ -0,0 +1 @@
+

src/query/mod.rs

@@ -0,0 +1,5 @@
+mod select;
+mod types;
+
+pub use select::*;
+pub use types::*;

src/query/select.rs

@@ -0,0 +1,77 @@
+use crate::{entity::*, RelationDef};
+use core::fmt::Debug;
+use core::marker::PhantomData;
+pub use sea_query::JoinType;
+use sea_query::{Expr, Iden, IntoIden, SelectStatement};
+use std::rc::Rc;
+use strum::IntoEnumIterator;
+
+#[derive(Debug)]
+pub struct Select<'s, E: 'static>
+where
+    E: Entity,
+{
+    select: SelectStatement,
+    entity: PhantomData<&'s E>,
+}
+
+impl<E: 'static> Select<'_, E>
+where
+    E: Entity,
+{
+    pub(crate) fn new(_: E) -> Self {
+        Self {
+            select: SelectStatement::new(),
+            entity: PhantomData,
+        }
+        .prepare_select()
+        .prepare_from()
+    }
+
+    fn prepare_select(mut self) -> Self {
+        let table = E::default().into_iden();
+        let columns: Vec<(Rc<dyn Iden>, E::Column)> =
+            E::Column::iter().map(|c| (Rc::clone(&table), c)).collect();
+        self.select.columns(columns);
+        self
+    }
+
+    fn prepare_from(mut self) -> Self {
+        self.select.from(E::default().into_iden());
+        self
+    }
+
+    fn prepare_join(mut self, join: JoinType, relation: RelationDef) -> Self {
+        let own_tbl = E::default().into_iden();
+        let to_tbl = &relation.to_tbl;
+        let owner_keys = relation.from_col;
+        let foreign_keys = relation.to_col;
+        let condition = match (owner_keys, foreign_keys) {
+            (Identity::Unary(o1), Identity::Unary(f1)) => {
+                Expr::tbl(Rc::clone(&own_tbl), o1).equals(Rc::clone(to_tbl), f1)
+            } // _ => panic!("Owner key and foreign key mismatch"),
+        };
+        self.select.join(join, Rc::clone(to_tbl), condition);
+        self
+    }
+
+    pub fn left_join(self, relation: RelationDef) -> Self {
+        self.prepare_join(JoinType::LeftJoin, relation)
+    }
+
+    pub fn right_join(self, relation: RelationDef) -> Self {
+        self.prepare_join(JoinType::RightJoin, relation)
+    }
+
+    pub fn inner_join(self, relation: RelationDef) -> Self {
+        self.prepare_join(JoinType::InnerJoin, relation)
+    }
+
+    pub fn query(&mut self) -> &mut SelectStatement {
+        &mut self.select
+    }
+
+    pub fn into_query(self) -> SelectStatement {
+        self.select
+    }
+}