diesel/
backend.rs

1//! Types which represent various database backends
2
3use byteorder::ByteOrder;
4
5use query_builder::bind_collector::BindCollector;
6use query_builder::QueryBuilder;
7use sql_types::{self, HasSqlType};
8
9/// A database backend
10///
11/// This trait represents the concept of a backend (e.g. "MySQL" vs "SQLite").
12/// It is separate from a [`Connection`](../connection/trait.Connection.html)
13/// to that backend.
14/// One backend may have multiple concrete connection implementations.
15///
16/// Implementations of this trait should not assume details about how the
17/// connection is implemented.
18/// For example, the `Pg` backend does not assume that `libpq` is being used.
19/// Implementations of this trait can and should care about details of the wire
20/// protocol used to communicated with the database.
21pub trait Backend
22where
23    Self: Sized,
24    Self: HasSqlType<sql_types::SmallInt>,
25    Self: HasSqlType<sql_types::Integer>,
26    Self: HasSqlType<sql_types::BigInt>,
27    Self: HasSqlType<sql_types::Float>,
28    Self: HasSqlType<sql_types::Double>,
29    Self: HasSqlType<sql_types::VarChar>,
30    Self: HasSqlType<sql_types::Text>,
31    Self: HasSqlType<sql_types::Binary>,
32    Self: HasSqlType<sql_types::Date>,
33    Self: HasSqlType<sql_types::Time>,
34    Self: HasSqlType<sql_types::Timestamp>,
35{
36    /// The concrete `QueryBuilder` implementation for this backend.
37    type QueryBuilder: QueryBuilder<Self>;
38    /// The concrete `BindCollector` implementation for this backend.
39    ///
40    /// Most backends should use [`RawBytesBindCollector`].
41    ///
42    /// [`RawBytesBindCollector`]: ../query_builder/bind_collector/struct.RawBytesBindCollector.html
43    type BindCollector: BindCollector<Self>;
44    /// The raw representation of a database value given to `FromSql`.
45    ///
46    /// Since most backends transmit data as opaque blobs of bytes, this type
47    /// is usually `[u8]`.
48    type RawValue: ?Sized;
49    /// What byte order is used to transmit integers?
50    ///
51    /// This type is only used if `RawValue` is `[u8]`.
52    type ByteOrder: ByteOrder;
53}
54
55/// Does this backend support `RETURNING` clauses?
56pub trait SupportsReturningClause {}
57/// Does this backend support the bare `DEFAULT` keyword?
58pub trait SupportsDefaultKeyword {}
59/// Does this backend use the standard `SAVEPOINT` syntax?
60pub trait UsesAnsiSavepointSyntax {}
61
62#[cfg(feature = "with-deprecated")]
63#[deprecated(since = "1.1.0", note = "use `sql_types::TypeMetadata` instead")]
64pub use sql_types::TypeMetadata;
diesel/backend.rs

diesel/
backend.rs
