use std::marker::PhantomData;
use expression::Expression;
use query_builder::{QueryBuilder, BuildQueryResult};
use query_source::{Table, Column};
use types::NativeSqlType;
pub trait Insertable<T: Table> {
type Columns: InsertableColumns<T>;
type Values: Expression<SqlType=<Self::Columns as InsertableColumns<T>>::SqlType>;
fn columns() -> Self::Columns;
fn values(self) -> Self::Values;
}
pub trait InsertableColumns<T: Table> {
type SqlType: NativeSqlType;
fn names(&self) -> String;
}
impl<'a, T, U> Insertable<T> for &'a [U] where
T: Table,
&'a U: Insertable<T>,
{
type Columns = <&'a U as Insertable<T>>::Columns;
type Values = InsertValues<'a, T, U>;
fn columns() -> Self::Columns {
<&'a U>::columns()
}
fn values(self) -> Self::Values {
InsertValues {
values: self,
_marker: PhantomData,
}
}
}
impl<'a, T, U> Insertable<T> for &'a Vec<U> where
T: Table,
&'a U: Insertable<T>,
{
type Columns = <&'a U as Insertable<T>>::Columns;
type Values = InsertValues<'a, T, U>;
fn columns() -> Self::Columns {
<&'a U>::columns()
}
fn values(self) -> Self::Values {
InsertValues {
values: &*self,
_marker: PhantomData,
}
}
}
pub struct InsertValues<'a, T, U: 'a> {
values: &'a [U],
_marker: PhantomData<T>,
}
impl<'a, T, U> Expression for InsertValues<'a, T, U> where
T: Table,
&'a U: Insertable<T>,
{
type SqlType = <<&'a U as Insertable<T>>::Columns as InsertableColumns<T>>::SqlType;
fn to_sql(&self, out: &mut QueryBuilder) -> BuildQueryResult {
self.to_insert_sql(out)
}
fn to_insert_sql(&self, out: &mut QueryBuilder) -> BuildQueryResult {
for (i, record) in self.values.into_iter().enumerate() {
if i != 0 {
out.push_sql(", ");
}
try!(record.values().to_insert_sql(out));
}
Ok(())
}
}
impl<C: Column<Table=T>, T: Table> InsertableColumns<T> for C {
type SqlType = <Self as Expression>::SqlType;
fn names(&self) -> String {
Self::name().to_string()
}
}