pqb 0.1.3

A PostgreSQL Query Builder
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
129
130
131
132
133
134
135

// Copyright 2025 FastLabs Developers
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use crate::SqlWriterValues;
use crate::expr::Expr;
use crate::expr::write_expr;
use crate::query::Returning;
use crate::query::With;
use crate::query::write_returning;
use crate::query::write_with;
use crate::types::Iden;
use crate::types::IntoIden;
use crate::types::IntoTableRef;
use crate::types::TableRef;
use crate::types::write_iden;
use crate::types::write_table_ref;
use crate::writer::SqlWriter;

/// Update existing rows in the table.
#[derive(Default, Debug, Clone, PartialEq)]
pub struct Update {
    table: Option<TableRef>,
    values: Vec<(Iden, Expr)>,
    conditions: Vec<Expr>,
    returning: Option<Returning>,
    with: Option<With>,
}

impl Update {
    /// Create a new UPDATE query.
    pub fn new() -> Self {
        Self::default()
    }

    /// Build the SQL string with placeholders and return collected values.
    pub fn to_values(&self) -> SqlWriterValues {
        let mut w = SqlWriterValues::new();
        write_update(&mut w, self);
        w
    }

    /// Convert the update statement to a PostgreSQL query string.
    pub fn to_sql(&self) -> String {
        let mut sql = String::new();
        write_update(&mut sql, self);
        sql
    }

    /// Specify which table to update.
    pub fn table<T>(mut self, table: T) -> Self
    where
        T: IntoTableRef,
    {
        self.table = Some(table.into());
        self
    }

    /// Update column values.
    pub fn values<T, I>(mut self, values: I) -> Self
    where
        T: IntoIden,
        I: IntoIterator<Item = (T, Expr)>,
    {
        for (k, v) in values.into_iter() {
            self.values.push((k.into_iden(), v));
        }
        self
    }

    /// And where condition.
    pub fn and_where<T>(mut self, expr: T) -> Self
    where
        T: Into<Expr>,
    {
        self.conditions.push(expr.into());
        self
    }

    /// RETURNING expressions.
    pub fn returning(mut self, returning: Returning) -> Self {
        self.returning = Some(returning);
        self
    }

    /// WITH clause.
    pub fn with(mut self, with: With) -> Self {
        self.with = Some(with);
        self
    }
}

pub(crate) fn write_update<W: SqlWriter>(w: &mut W, update: &Update) {
    if let Some(with) = &update.with {
        write_with(w, with);
        w.push_char(' ');
    }

    w.push_str("UPDATE ");

    if let Some(table) = &update.table {
        write_table_ref(w, table);
    }

    if !update.values.is_empty() {
        w.push_str(" SET ");
        for (i, (col, val)) in update.values.iter().enumerate() {
            if i > 0 {
                w.push_str(", ");
            }
            write_iden(w, col);
            w.push_str(" = ");
            write_expr(w, val);
        }
    }

    if let Some(condition) = Expr::from_conditions(update.conditions.clone()) {
        w.push_str(" WHERE ");
        write_expr(w, &condition);
    }

    if let Some(returning) = &update.returning {
        write_returning(w, returning);
    }
}