diesel 1.4.6

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
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143

use expression::operators::{Concat, Like, NotLike};
use expression::{AsExpression, Expression};
use sql_types::{Nullable, Text};

/// Methods present on text expressions
pub trait TextExpressionMethods: Expression + Sized {
    /// Concatenates two strings using the `||` operator.
    ///
    /// # Example
    ///
    /// ```rust
    /// # #[macro_use] extern crate diesel;
    /// # include!("../doctest_setup.rs");
    /// #
    /// # table! {
    /// #     users {
    /// #         id -> Integer,
    /// #         name -> VarChar,
    /// #         hair_color -> Nullable<Text>,
    /// #     }
    /// # }
    /// #
    /// # fn main() {
    /// #     use self::users::dsl::*;
    /// #     use diesel::insert_into;
    /// #
    /// #     let connection = connection_no_data();
    /// #     connection.execute("CREATE TABLE users (
    /// #         id INTEGER PRIMARY KEY,
    /// #         name VARCHAR(255) NOT NULL,
    /// #         hair_color VARCHAR(255)
    /// #     )").unwrap();
    /// #
    /// #     insert_into(users)
    /// #         .values(&vec![
    /// #             (id.eq(1), name.eq("Sean"), hair_color.eq(Some("Green"))),
    /// #             (id.eq(2), name.eq("Tess"), hair_color.eq(None)),
    /// #         ])
    /// #         .execute(&connection)
    /// #         .unwrap();
    /// #
    /// let names = users.select(name.concat(" the Greatest")).load(&connection);
    /// let expected_names = vec![
    ///     "Sean the Greatest".to_string(),
    ///     "Tess the Greatest".to_string(),
    /// ];
    /// assert_eq!(Ok(expected_names), names);
    ///
    /// // If the value is nullable, the output will be nullable
    /// let names = users.select(hair_color.concat("ish")).load(&connection);
    /// let expected_names = vec![
    ///     Some("Greenish".to_string()),
    ///     None,
    /// ];
    /// assert_eq!(Ok(expected_names), names);
    /// # }
    /// ```
    fn concat<T: AsExpression<Self::SqlType>>(self, other: T) -> Concat<Self, T::Expression> {
        Concat::new(self, other.as_expression())
    }

    /// Returns a SQL `LIKE` expression
    ///
    /// This method is case insensitive for SQLite and MySQL.
    /// On PostgreSQL, `LIKE` is case sensitive. You may use
    /// [`ilike()`](../expression_methods/trait.PgTextExpressionMethods.html#method.ilike)
    /// for case insensitive comparison on PostgreSQL.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # #[macro_use] extern crate diesel;
    /// # include!("../doctest_setup.rs");
    /// #
    /// # fn main() {
    /// #     run_test().unwrap();
    /// # }
    /// #
    /// # fn run_test() -> QueryResult<()> {
    /// #     use schema::users::dsl::*;
    /// #     let connection = establish_connection();
    /// #
    /// let starts_with_s = users
    ///     .select(name)
    ///     .filter(name.like("S%"))
    ///     .load::<String>(&connection)?;
    /// assert_eq!(vec!["Sean"], starts_with_s);
    /// #     Ok(())
    /// # }
    /// ```
    fn like<T: AsExpression<Self::SqlType>>(self, other: T) -> Like<Self, T::Expression> {
        Like::new(self.as_expression(), other.as_expression())
    }

    /// Returns a SQL `NOT LIKE` expression
    ///
    /// This method is case insensitive for SQLite and MySQL.
    /// On PostgreSQL `NOT LIKE` is case sensitive. You may use
    /// [`not_ilike()`](../expression_methods/trait.PgTextExpressionMethods.html#method.not_ilike)
    /// for case insensitive comparison on PostgreSQL.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # #[macro_use] extern crate diesel;
    /// # include!("../doctest_setup.rs");
    /// #
    /// # fn main() {
    /// #     run_test().unwrap();
    /// # }
    /// #
    /// # fn run_test() -> QueryResult<()> {
    /// #     use schema::users::dsl::*;
    /// #     let connection = establish_connection();
    /// #
    /// let doesnt_start_with_s = users
    ///     .select(name)
    ///     .filter(name.not_like("S%"))
    ///     .load::<String>(&connection)?;
    /// assert_eq!(vec!["Tess"], doesnt_start_with_s);
    /// #     Ok(())
    /// # }
    /// ```
    fn not_like<T: AsExpression<Self::SqlType>>(self, other: T) -> NotLike<Self, T::Expression> {
        NotLike::new(self.as_expression(), other.as_expression())
    }
}

#[doc(hidden)]
/// Marker trait used to implement `TextExpressionMethods` on the appropriate
/// types. Once coherence takes associated types into account, we can remove
/// this trait.
pub trait TextOrNullableText {}

impl TextOrNullableText for Text {}
impl TextOrNullableText for Nullable<Text> {}

impl<T> TextExpressionMethods for T
where
    T: Expression,
    T::SqlType: TextOrNullableText,
{
}