drizzle_core/expr/
seq.rs

1//! `PostgreSQL` sequence functions.
2//!
3//! These functions interact with `PostgreSQL` sequences (serial/identity columns).
4
5use crate::dialect::DialectTypes;
6use crate::sql::SQL;
7use crate::traits::SQLParam;
8use crate::types::Textual;
9
10use super::{AggOr, AggregateKind, Expr, NonNull, Nullability, SQLExpr, Scalar};
11
12use crate::PostgresDialect;
13
14#[diagnostic::on_unimplemented(
15    message = "sequence functions are not available for this dialect",
16    label = "sequence functions require PostgreSQL"
17)]
18pub trait SequenceSupport {}
19
20impl SequenceSupport for PostgresDialect {}
21
22/// NEXTVAL - advances a sequence and returns its new value (`PostgreSQL`).
23///
24/// The argument is the sequence name as a text expression.
25///
26/// # Example
27///
28/// ```rust
29/// # let _ = r####"
30/// use drizzle_core::expr::nextval;
31///
32/// // SELECT NEXTVAL('users_id_seq')
33/// let next_id = nextval("users_id_seq");
34/// # "####;
35/// ```
36pub fn nextval<'a, V, E>(
37    sequence: E,
38) -> SQLExpr<'a, V, <V::DialectMarker as DialectTypes>::BigInt, NonNull, Scalar>
39where
40    V: SQLParam + 'a,
41    V::DialectMarker: SequenceSupport,
42    E: Expr<'a, V>,
43    E::SQLType: Textual,
44{
45    SQLExpr::new(SQL::func("NEXTVAL", sequence.into_sql()))
46}
47
48/// CURRVAL - returns the most recently obtained value from a sequence (`PostgreSQL`).
49///
50/// Must be called after `NEXTVAL` has been used on the sequence in the current session.
51///
52/// # Example
53///
54/// ```rust
55/// # let _ = r####"
56/// use drizzle_core::expr::currval;
57///
58/// // SELECT CURRVAL('users_id_seq')
59/// let current_id = currval("users_id_seq");
60/// # "####;
61/// ```
62pub fn currval<'a, V, E>(
63    sequence: E,
64) -> SQLExpr<'a, V, <V::DialectMarker as DialectTypes>::BigInt, NonNull, Scalar>
65where
66    V: SQLParam + 'a,
67    V::DialectMarker: SequenceSupport,
68    E: Expr<'a, V>,
69    E::SQLType: Textual,
70{
71    SQLExpr::new(SQL::func("CURRVAL", sequence.into_sql()))
72}
73
74/// SETVAL - sets a sequence's current value (`PostgreSQL`).
75///
76/// # Example
77///
78/// ```rust
79/// # let _ = r####"
80/// use drizzle_core::expr::setval;
81///
82/// // SELECT SETVAL('users_id_seq', 100)
83/// let set_id = setval("users_id_seq", 100);
84/// # "####;
85/// ```
86#[allow(clippy::type_complexity)]
87pub fn setval<'a, V, E, N>(
88    sequence: E,
89    value: N,
90) -> SQLExpr<
91    'a,
92    V,
93    <V::DialectMarker as DialectTypes>::BigInt,
94    <E::Nullable as super::NullOr<N::Nullable>>::Output,
95    <E::Aggregate as AggOr<N::Aggregate>>::Output,
96>
97where
98    V: SQLParam + 'a,
99    V::DialectMarker: SequenceSupport,
100    E: Expr<'a, V>,
101    E::SQLType: Textual,
102    N: Expr<'a, V>,
103    N::SQLType: crate::types::Integral,
104    E::Nullable: super::NullOr<N::Nullable>,
105    N::Nullable: Nullability,
106    E::Aggregate: AggOr<N::Aggregate>,
107    N::Aggregate: AggregateKind,
108{
109    SQLExpr::new(SQL::func(
110        "SETVAL",
111        sequence
112            .into_sql()
113            .push(crate::Token::COMMA)
114            .append(value.into_sql()),
115    ))
116}
drizzle_core/expr/seq.rs

drizzle_core/expr/
seq.rs
