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use std::marker::PhantomData;
use super::Query;
use crate::backend::{Backend, DieselReserveSpecialization};
use crate::connection::Connection;
use crate::query_builder::{AstPass, QueryFragment, QueryId};
use crate::query_dsl::RunQueryDsl;
use crate::result::QueryResult;
use crate::serialize::ToSql;
use crate::sql_types::{HasSqlType, Untyped};
#[derive(Debug, Clone)]
#[must_use = "Queries are only executed when calling `load`, `get_result` or similar."]
/// The return value of `sql_query`.
///
/// Unlike most queries in Diesel, `SqlQuery` loads its data by column name,
/// rather than by index. This means that you cannot deserialize this query into
/// a tuple, and any structs used must implement `QueryableByName`.
///
/// See [`sql_query`](crate::sql_query()) for examples.
pub struct SqlQuery<Inner = self::private::Empty> {
inner: Inner,
query: String,
}
impl<Inner> SqlQuery<Inner> {
pub(crate) fn new(inner: Inner, query: String) -> Self {
SqlQuery { inner, query }
}
/// Bind a value for use with this SQL query. The given query should have
/// placeholders that vary based on the database type,
/// like [SQLite Parameter](https://sqlite.org/lang_expr.html#varparam) syntax,
/// [PostgreSQL PREPARE syntax](https://www.postgresql.org/docs/current/sql-prepare.html),
/// or [MySQL bind syntax](https://dev.mysql.com/doc/refman/8.0/en/mysql-stmt-bind-param.html).
///
/// # Safety
///
/// This function should be used with care, as Diesel cannot validate that
/// the value is of the right type nor can it validate that you have passed
/// the correct number of parameters.
///
/// # Example
///
/// ```
/// # include!("../doctest_setup.rs");
/// #
/// # use schema::users;
/// #
/// # #[derive(QueryableByName, Debug, PartialEq)]
/// # #[diesel(table_name = users)]
/// # struct User {
/// # id: i32,
/// # name: String,
/// # }
/// #
/// # fn main() {
/// # use diesel::sql_query;
/// # use diesel::sql_types::{Integer, Text};
/// #
/// # let connection = &mut establish_connection();
/// # diesel::insert_into(users::table)
/// # .values(users::name.eq("Jim"))
/// # .execute(connection).unwrap();
/// # #[cfg(feature = "postgres")]
/// # let users = sql_query("SELECT * FROM users WHERE id > $1 AND name != $2");
/// # #[cfg(not(feature = "postgres"))]
/// let users = sql_query("SELECT * FROM users WHERE id > ? AND name <> ?")
/// # ;
/// # let users = users
/// .bind::<Integer, _>(1)
/// .bind::<Text, _>("Tess")
/// .get_results(connection);
/// let expected_users = vec![
/// User { id: 3, name: "Jim".into() },
/// ];
/// assert_eq!(Ok(expected_users), users);
/// # }
/// ```
pub fn bind<ST, Value>(self, value: Value) -> UncheckedBind<Self, Value, ST> {
UncheckedBind::new(self, value)
}
/// Internally boxes future calls on `bind` and `sql` so that they don't
/// change the type.
///
/// This allows doing things you otherwise couldn't do, e.g. `bind`ing in a
/// loop.
pub fn into_boxed<'f, DB: Backend>(self) -> BoxedSqlQuery<'f, DB, Self> {
BoxedSqlQuery::new(self)
}
/// Appends a piece of SQL code at the end.
pub fn sql<T: AsRef<str>>(mut self, sql: T) -> Self {
self.query += sql.as_ref();
self
}
}
impl SqlQuery {
pub(crate) fn from_sql(query: String) -> SqlQuery {
Self {
inner: self::private::Empty,
query,
}
}
}
impl<DB, Inner> QueryFragment<DB> for SqlQuery<Inner>
where
DB: Backend + DieselReserveSpecialization,
Inner: QueryFragment<DB>,
{
fn walk_ast<'b>(&'b self, mut out: AstPass<'_, 'b, DB>) -> QueryResult<()> {
out.unsafe_to_cache_prepared();
self.inner.walk_ast(out.reborrow())?;
out.push_sql(&self.query);
Ok(())
}
}
impl<Inner> QueryId for SqlQuery<Inner> {
type QueryId = ();
const HAS_STATIC_QUERY_ID: bool = false;
}
impl<Inner> Query for SqlQuery<Inner> {
type SqlType = Untyped;
}
impl<Inner, Conn> RunQueryDsl<Conn> for SqlQuery<Inner> {}
#[derive(Debug, Clone, Copy)]
#[must_use = "Queries are only executed when calling `load`, `get_result` or similar."]
/// Returned by the [`SqlQuery::bind()`] method when binding a value to a fragment of SQL.
///
pub struct UncheckedBind<Query, Value, ST> {
query: Query,
value: Value,
_marker: PhantomData<ST>,
}
impl<Query, Value, ST> UncheckedBind<Query, Value, ST> {
pub fn new(query: Query, value: Value) -> Self {
UncheckedBind {
query,
value,
_marker: PhantomData,
}
}
pub fn bind<ST2, Value2>(self, value: Value2) -> UncheckedBind<Self, Value2, ST2> {
UncheckedBind::new(self, value)
}
pub fn into_boxed<'f, DB: Backend>(self) -> BoxedSqlQuery<'f, DB, Self> {
BoxedSqlQuery::new(self)
}
/// Construct a full SQL query using raw SQL.
///
/// This function exists for cases where a query needs to be written that is not
/// supported by the query builder. Unlike most queries in Diesel, `sql_query`
/// will deserialize its data by name, not by index. That means that you cannot
/// deserialize into a tuple, and structs which you deserialize from this
/// function will need to have `#[derive(QueryableByName)]`.
///
/// This function is intended for use when you want to write the entire query
/// using raw SQL. If you only need a small bit of raw SQL in your query, use
/// [`sql`](dsl::sql()) instead.
///
/// Query parameters can be bound into the raw query using [`SqlQuery::bind()`].
///
/// # Safety
///
/// The implementation of `QueryableByName` will assume that columns with a
/// given name will have a certain type. The compiler will be unable to verify
/// that the given type is correct. If your query returns a column of an
/// unexpected type, the result may have the wrong value, or return an error.
///
/// # Examples
///
/// ```rust
/// # include!("../doctest_setup.rs");
/// #
/// # use schema::users;
/// #
/// # #[derive(QueryableByName, Debug, PartialEq)]
/// # #[diesel(table_name = users)]
/// # struct User {
/// # id: i32,
/// # name: String,
/// # }
/// #
/// # fn main() {
/// # use diesel::sql_query;
/// # use diesel::sql_types::{Integer, Text};
/// #
/// # let connection = &mut establish_connection();
/// # diesel::insert_into(users::table)
/// # .values(users::name.eq("Jim"))
/// # .execute(connection).unwrap();
/// # #[cfg(feature = "postgres")]
/// # let users = sql_query("SELECT * FROM users WHERE id > $1 AND name != $2");
/// # #[cfg(not(feature = "postgres"))]
/// let users = sql_query("SELECT * FROM users WHERE id > ? AND name <> ?")
/// # ;
/// # let users = users
/// .bind::<Integer, _>(1)
/// .bind::<Text, _>("Tess")
/// .get_results(connection);
/// let expected_users = vec![
/// User { id: 3, name: "Jim".into() },
/// ];
/// assert_eq!(Ok(expected_users), users);
/// # }
/// ```
/// [`SqlQuery::bind()`]: query_builder::SqlQuery::bind()
pub fn sql<T: Into<String>>(self, sql: T) -> SqlQuery<Self> {
SqlQuery::new(self, sql.into())
}
}
impl<Query, Value, ST> QueryId for UncheckedBind<Query, Value, ST>
where
Query: QueryId,
ST: QueryId,
{
type QueryId = UncheckedBind<Query::QueryId, (), ST::QueryId>;
const HAS_STATIC_QUERY_ID: bool = Query::HAS_STATIC_QUERY_ID && ST::HAS_STATIC_QUERY_ID;
}
impl<Query, Value, ST, DB> QueryFragment<DB> for UncheckedBind<Query, Value, ST>
where
DB: Backend + HasSqlType<ST> + DieselReserveSpecialization,
Query: QueryFragment<DB>,
Value: ToSql<ST, DB>,
{
fn walk_ast<'b>(&'b self, mut out: AstPass<'_, 'b, DB>) -> QueryResult<()> {
self.query.walk_ast(out.reborrow())?;
out.push_bind_param_value_only(&self.value)?;
Ok(())
}
}
impl<Q, Value, ST> Query for UncheckedBind<Q, Value, ST> {
type SqlType = Untyped;
}
impl<Conn, Query, Value, ST> RunQueryDsl<Conn> for UncheckedBind<Query, Value, ST> {}
#[must_use = "Queries are only executed when calling `load`, `get_result`, or similar."]
/// See [`SqlQuery::into_boxed`].
///
/// [`SqlQuery::into_boxed`]: SqlQuery::into_boxed()
#[allow(missing_debug_implementations)]
pub struct BoxedSqlQuery<'f, DB: Backend, Query> {
query: Query,
sql: String,
binds: Vec<Box<dyn QueryFragment<DB> + Send + 'f>>,
}
struct RawBind<ST, U> {
value: U,
p: PhantomData<ST>,
}
impl<ST, U, DB> QueryFragment<DB> for RawBind<ST, U>
where
DB: Backend + HasSqlType<ST>,
U: ToSql<ST, DB>,
{
fn walk_ast<'b>(&'b self, mut pass: AstPass<'_, 'b, DB>) -> QueryResult<()> {
pass.push_bind_param_value_only(&self.value)
}
}
impl<'f, DB: Backend, Query> BoxedSqlQuery<'f, DB, Query> {
pub(crate) fn new(query: Query) -> Self {
BoxedSqlQuery {
query,
sql: "".to_string(),
binds: vec![],
}
}
/// See [`SqlQuery::bind`].
///
/// [`SqlQuery::bind`]: SqlQuery::bind()
pub fn bind<BindSt, Value>(mut self, b: Value) -> Self
where
DB: HasSqlType<BindSt>,
Value: ToSql<BindSt, DB> + Send + 'f,
BindSt: Send + 'f,
{
self.binds.push(Box::new(RawBind {
value: b,
p: PhantomData,
}) as Box<_>);
self
}
/// See [`SqlQuery::sql`].
///
/// [`SqlQuery::sql`]: SqlQuery::sql()
pub fn sql<T: AsRef<str>>(mut self, sql: T) -> Self {
self.sql += sql.as_ref();
self
}
}
impl<DB, Query> QueryFragment<DB> for BoxedSqlQuery<'_, DB, Query>
where
DB: Backend + DieselReserveSpecialization,
Query: QueryFragment<DB>,
{
fn walk_ast<'b>(&'b self, mut out: AstPass<'_, 'b, DB>) -> QueryResult<()> {
out.unsafe_to_cache_prepared();
self.query.walk_ast(out.reborrow())?;
out.push_sql(&self.sql);
for b in &self.binds {
b.walk_ast(out.reborrow())?;
}
Ok(())
}
}
impl<DB: Backend, Query> QueryId for BoxedSqlQuery<'_, DB, Query> {
type QueryId = ();
const HAS_STATIC_QUERY_ID: bool = false;
}
impl<DB, Q> Query for BoxedSqlQuery<'_, DB, Q>
where
DB: Backend,
{
type SqlType = Untyped;
}
impl<Conn: Connection, Query> RunQueryDsl<Conn> for BoxedSqlQuery<'_, Conn::Backend, Query> {}
mod private {
use crate::backend::{Backend, DieselReserveSpecialization};
use crate::query_builder::{QueryFragment, QueryId};
#[derive(Debug, Clone, Copy, QueryId)]
pub struct Empty;
impl<DB> QueryFragment<DB> for Empty
where
DB: Backend + DieselReserveSpecialization,
{
fn walk_ast<'b>(
&'b self,
_pass: crate::query_builder::AstPass<'_, 'b, DB>,
) -> crate::QueryResult<()> {
Ok(())
}
}
}
#[cfg(test)]
mod tests {
fn assert_send<S: Send>(_: S) {}
#[test]
fn check_boxed_sql_query_is_send() {
let query = crate::sql_query("SELECT 1")
.into_boxed::<<crate::test_helpers::TestConnection as crate::Connection>::Backend>(
);
assert_send(query);
}
}