diesel 2.3.8

A safe, extensible ORM and Query Builder for PostgreSQL, SQLite, and MySQL
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128

use std::marker::PhantomData;

use crate::backend::sql_dialect::on_conflict_clause;
use crate::expression::{AppearsOnTable, Expression};
use crate::query_builder::*;
use crate::query_source::*;

#[doc(hidden)]
#[derive(Debug, Clone, Copy, QueryId)]
pub struct DoNothing<T>(PhantomData<T>);

impl<T> DoNothing<T> {
    pub(crate) fn new() -> Self {
        Self(PhantomData)
    }
}

impl<T, DB> QueryFragment<DB> for DoNothing<T>
where
    DB: Backend,
    Self: QueryFragment<DB, DB::OnConflictClause>,
{
    fn walk_ast<'b>(&'b self, pass: AstPass<'_, 'b, DB>) -> QueryResult<()> {
        <Self as QueryFragment<DB, DB::OnConflictClause>>::walk_ast(self, pass)
    }
}

impl<DB, T, SD> QueryFragment<DB, SD> for DoNothing<T>
where
    DB: Backend<OnConflictClause = SD>,
    SD: on_conflict_clause::PgLikeOnConflictClause,
{
    fn walk_ast<'b>(&'b self, mut out: AstPass<'_, 'b, DB>) -> QueryResult<()> {
        out.push_sql(" DO NOTHING");
        Ok(())
    }
}

#[doc(hidden)]
#[derive(Debug, Clone, Copy, QueryId)]
pub struct DoUpdate<T, Tab> {
    pub(crate) changeset: T,
    tab: PhantomData<Tab>,
}

impl<T, Tab> DoUpdate<T, Tab> {
    pub(crate) fn new(changeset: T) -> Self {
        DoUpdate {
            changeset,
            tab: PhantomData,
        }
    }
}

impl<DB, T, Tab> QueryFragment<DB> for DoUpdate<T, Tab>
where
    DB: Backend,
    Self: QueryFragment<DB, DB::OnConflictClause>,
{
    fn walk_ast<'b>(&'b self, pass: AstPass<'_, 'b, DB>) -> QueryResult<()> {
        <Self as QueryFragment<DB, DB::OnConflictClause>>::walk_ast(self, pass)
    }
}

impl<DB, T, Tab, SD> QueryFragment<DB, SD> for DoUpdate<T, Tab>
where
    DB: Backend<OnConflictClause = SD>,
    T: QueryFragment<DB>,
    SD: on_conflict_clause::PgLikeOnConflictClause,
{
    fn walk_ast<'b>(&'b self, mut out: AstPass<'_, 'b, DB>) -> QueryResult<()> {
        out.unsafe_to_cache_prepared();
        if self.changeset.is_noop(out.backend())? {
            out.push_sql(" DO NOTHING");
        } else {
            out.push_sql(" DO UPDATE SET ");
            self.changeset.walk_ast(out.reborrow())?;
        }
        Ok(())
    }
}

#[doc(hidden)]
#[derive(Debug, Clone, Copy, QueryId)]
pub struct Excluded<T>(T);

impl<T> Excluded<T> {
    pub(crate) fn new(t: T) -> Self {
        Excluded(t)
    }
}

impl<DB, T> QueryFragment<DB> for Excluded<T>
where
    DB: Backend,
    Self: QueryFragment<DB, DB::OnConflictClause>,
{
    fn walk_ast<'b>(&'b self, pass: AstPass<'_, 'b, DB>) -> QueryResult<()> {
        <Self as QueryFragment<DB, DB::OnConflictClause>>::walk_ast(self, pass)
    }
}

impl<DB, T, SD> QueryFragment<DB, SD> for Excluded<T>
where
    DB: Backend<OnConflictClause = SD>,
    T: Column,
    SD: on_conflict_clause::PgLikeOnConflictClause,
{
    fn walk_ast<'b>(&'b self, mut out: AstPass<'_, 'b, DB>) -> QueryResult<()> {
        out.push_sql("excluded.");
        out.push_identifier(T::NAME)?;
        Ok(())
    }
}

impl<T> Expression for Excluded<T>
where
    T: Expression,
{
    type SqlType = T::SqlType;
}

impl<T> AppearsOnTable<T::Table> for Excluded<T>
where
    T: Column,
    Excluded<T>: Expression,
{
}