sea-orm/src/query/select.rs
2021-05-12 14:41:09 +08:00

398 lines
11 KiB
Rust

use crate::{
ColumnTrait, EntityTrait, Identity, Iterable, ModelTrait, PrimaryKeyOfModel, Related,
RelationDef, Statement,
};
use core::fmt::Debug;
use core::marker::PhantomData;
pub use sea_query::JoinType;
use sea_query::{
Alias, Expr, Iden, IntoColumnRef, IntoIden, Order, QueryBuilder, SelectExpr, SelectStatement,
SimpleExpr,
};
use std::rc::Rc;
#[derive(Clone, Debug)]
pub struct Select<E: 'static>
where
E: EntityTrait,
{
pub(crate) query: SelectStatement,
pub(crate) entity: PhantomData<E>,
}
pub trait IntoSimpleExpr {
fn into_simple_expr(self) -> SimpleExpr;
}
impl<C> IntoSimpleExpr for C
where
C: ColumnTrait,
{
fn into_simple_expr(self) -> SimpleExpr {
SimpleExpr::Column(self.as_column_ref().into_column_ref())
}
}
impl IntoSimpleExpr for SimpleExpr {
fn into_simple_expr(self) -> SimpleExpr {
self
}
}
impl<E: 'static> Select<E>
where
E: EntityTrait,
{
pub(crate) fn new() -> Self {
Self {
query: SelectStatement::new(),
entity: PhantomData,
}
.prepare_select()
.prepare_from()
}
fn prepare_select(mut self) -> Self {
self.query.columns(self.column_list());
self
}
fn column_list(&self) -> Vec<(Rc<dyn Iden>, E::Column)> {
let table = Rc::new(E::default()) as Rc<dyn Iden>;
E::Column::iter().map(|col| (table.clone(), col)).collect()
}
fn prepare_from(mut self) -> Self {
self.query.from(E::default().into_iden());
self
}
pub fn select_only(mut self) -> Self {
self.query.clear_selects();
self
}
/// Add a select column
/// ```
/// use sea_orm::{ColumnTrait, EntityTrait, tests_cfg::cake, sea_query::PostgresQueryBuilder};
///
/// assert_eq!(
/// cake::Entity::find()
/// .select_only()
/// .column(cake::Column::Name)
/// .build(PostgresQueryBuilder)
/// .to_string(),
/// r#"SELECT "cake"."name" FROM "cake""#
/// );
/// ```
pub fn column<C>(mut self, col: C) -> Self
where
C: IntoSimpleExpr,
{
self.query.expr(SelectExpr {
expr: col.into_simple_expr(),
alias: None,
});
self
}
/// Add a select column with alias
/// ```
/// use sea_orm::{ColumnTrait, EntityTrait, tests_cfg::cake, sea_query::PostgresQueryBuilder};
///
/// assert_eq!(
/// cake::Entity::find()
/// .select_only()
/// .column_as(cake::Column::Id.count(), "count")
/// .build(PostgresQueryBuilder)
/// .to_string(),
/// r#"SELECT COUNT("cake"."id") AS "count" FROM "cake""#
/// );
/// ```
pub fn column_as<C>(mut self, col: C, alias: &str) -> Self
where
C: IntoSimpleExpr,
{
self.query.expr(SelectExpr {
expr: col.into_simple_expr(),
alias: Some(Rc::new(Alias::new(alias))),
});
self
}
/// Add an AND WHERE expression
/// ```
/// use sea_orm::{ColumnTrait, EntityTrait, tests_cfg::cake, sea_query::MysqlQueryBuilder};
///
/// assert_eq!(
/// cake::Entity::find()
/// .filter(cake::Column::Id.eq(5))
/// .build(MysqlQueryBuilder)
/// .to_string(),
/// "SELECT `cake`.`id`, `cake`.`name` FROM `cake` WHERE `cake`.`id` = 5"
/// );
/// ```
pub fn filter(mut self, expr: SimpleExpr) -> Self {
self.query.and_where(expr);
self
}
pub fn belongs_to<R>(self, model: &R::Model) -> Self
where
R: EntityTrait + Related<E>,
R::PrimaryKey: PrimaryKeyOfModel<R::Model>,
{
if let Some(key) = R::PrimaryKey::iter().next() {
// TODO: supporting composite primary key
let col = key.into_column();
self.filter(col.eq(model.get(col)))
} else {
panic!("undefined primary key");
}
}
/// Add a group by column
/// ```
/// use sea_orm::{ColumnTrait, EntityTrait, tests_cfg::cake, sea_query::PostgresQueryBuilder};
///
/// assert_eq!(
/// cake::Entity::find()
/// .select_only()
/// .column(cake::Column::Name)
/// .group_by(cake::Column::Name)
/// .build(PostgresQueryBuilder)
/// .to_string(),
/// r#"SELECT "cake"."name" FROM "cake" GROUP BY "cake"."name""#
/// );
/// ```
pub fn group_by<C>(mut self, col: C) -> Self
where
C: IntoSimpleExpr,
{
self.query.add_group_by(vec![col.into_simple_expr()]);
self
}
/// Add an order_by expression (ascending)
/// ```
/// use sea_orm::{EntityTrait, tests_cfg::cake, sea_query::MysqlQueryBuilder};
///
/// assert_eq!(
/// cake::Entity::find()
/// .order_by(cake::Column::Id)
/// .build(MysqlQueryBuilder)
/// .to_string(),
/// "SELECT `cake`.`id`, `cake`.`name` FROM `cake` ORDER BY `cake`.`id` ASC"
/// );
/// ```
pub fn order_by<C>(mut self, col: C) -> Self
where
C: IntoSimpleExpr,
{
self.query.order_by_expr(col.into_simple_expr(), Order::Asc);
self
}
/// Add an order_by expression (descending)
/// ```
/// use sea_orm::{EntityTrait, tests_cfg::cake, sea_query::MysqlQueryBuilder};
///
/// assert_eq!(
/// cake::Entity::find()
/// .order_by_desc(cake::Column::Id)
/// .build(MysqlQueryBuilder)
/// .to_string(),
/// "SELECT `cake`.`id`, `cake`.`name` FROM `cake` ORDER BY `cake`.`id` DESC"
/// );
/// ```
pub fn order_by_desc<C>(mut self, col: C) -> Self
where
C: IntoSimpleExpr,
{
self.query
.order_by_expr(col.into_simple_expr(), Order::Desc);
self
}
/// Join via [`RelationDef`].
pub fn join(mut self, join: JoinType, rel: RelationDef) -> Self {
let own_tbl = E::default().into_iden();
let to_tbl = rel.to_tbl.clone();
let owner_keys = rel.from_col;
let foreign_keys = rel.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.query.join(join, Rc::clone(&to_tbl), condition);
self
}
/// Join via [`RelationDef`] but in reverse direction.
/// Assume when there exist a relation A -> B.
/// You can reverse join B <- A.
pub fn join_rev(mut self, join: JoinType, rel: RelationDef) -> Self {
let from_tbl = rel.from_tbl.clone();
let to_tbl = rel.to_tbl.clone();
let owner_keys = rel.from_col;
let foreign_keys = rel.to_col;
let condition = match (owner_keys, foreign_keys) {
(Identity::Unary(o1), Identity::Unary(f1)) => {
Expr::tbl(Rc::clone(&from_tbl), o1).equals(Rc::clone(&to_tbl), f1)
} // _ => panic!("Owner key and foreign key mismatch"),
};
self.query.join(join, Rc::clone(&from_tbl), condition);
self
}
/// Left Join with a Related Entity.
pub fn left_join<R>(self, _: R) -> Self
where
R: EntityTrait,
E: Related<R>,
{
self.join(JoinType::LeftJoin, E::to())
}
/// Right Join with a Related Entity.
pub fn right_join<R>(self, _: R) -> Self
where
R: EntityTrait,
E: Related<R>,
{
self.join(JoinType::RightJoin, E::to())
}
/// Inner Join with a Related Entity.
pub fn inner_join<R>(self, _: R) -> Self
where
R: EntityTrait,
E: Related<R>,
{
self.join(JoinType::InnerJoin, E::to())
}
/// Join with an Entity Related to me.
pub fn reverse_join<R>(self, _: R) -> Self
where
R: EntityTrait + Related<E>,
{
self.join_rev(JoinType::InnerJoin, R::to())
}
/// Get a mutable ref to the query builder
pub fn query(&mut self) -> &mut SelectStatement {
&mut self.query
}
/// Get an immutable ref to the query builder
pub fn as_query(&self) -> &SelectStatement {
&self.query
}
/// Take ownership of the query builder
pub fn into_query(self) -> SelectStatement {
self.query
}
/// Build the query as [`Statement`]
pub fn build<B>(&self, builder: B) -> Statement
where
B: QueryBuilder,
{
self.as_query().build(builder).into()
}
}
#[cfg(test)]
mod tests {
use crate::tests_cfg::{cake, fruit};
use crate::{ColumnTrait, EntityTrait};
use sea_query::MysqlQueryBuilder;
#[test]
fn join_1() {
assert_eq!(
cake::Entity::find()
.left_join(fruit::Entity)
.build(MysqlQueryBuilder)
.to_string(),
[
"SELECT `cake`.`id`, `cake`.`name` FROM `cake`",
"LEFT JOIN `fruit` ON `cake`.`id` = `fruit`.`cake_id`",
]
.join(" ")
);
}
#[test]
fn join_2() {
assert_eq!(
cake::Entity::find()
.inner_join(fruit::Entity)
.filter(fruit::Column::Name.contains("cherry"))
.build(MysqlQueryBuilder)
.to_string(),
[
"SELECT `cake`.`id`, `cake`.`name` FROM `cake`",
"INNER JOIN `fruit` ON `cake`.`id` = `fruit`.`cake_id`",
"WHERE `fruit`.`name` LIKE \'%cherry%\'"
]
.join(" ")
);
}
#[test]
fn join_3() {
assert_eq!(
fruit::Entity::find()
.reverse_join(cake::Entity)
.build(MysqlQueryBuilder)
.to_string(),
[
"SELECT `fruit`.`id`, `fruit`.`name`, `fruit`.`cake_id` FROM `fruit`",
"INNER JOIN `cake` ON `cake`.`id` = `fruit`.`cake_id`",
]
.join(" ")
);
}
#[test]
fn join_4() {
use crate::{Related, Select};
let find_fruit: Select<fruit::Entity> = cake::Entity::find_related();
assert_eq!(
find_fruit
.filter(cake::Column::Id.eq(11))
.build(MysqlQueryBuilder)
.to_string(),
[
"SELECT `fruit`.`id`, `fruit`.`name`, `fruit`.`cake_id` FROM `fruit`",
"INNER JOIN `cake` ON `cake`.`id` = `fruit`.`cake_id`",
"WHERE `cake`.`id` = 11",
]
.join(" ")
);
}
#[test]
fn join_5() {
let cake_model = cake::Model {
id: 12,
name: "".to_owned(),
};
assert_eq!(
cake_model.find_fruit().build(MysqlQueryBuilder).to_string(),
[
"SELECT `fruit`.`id`, `fruit`.`name`, `fruit`.`cake_id` FROM `fruit`",
"INNER JOIN `cake` ON `cake`.`id` = `fruit`.`cake_id`",
"WHERE `cake`.`id` = 12",
]
.join(" ")
);
}
}