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//! Conversions between Rust and SQL types. //! //! To see how each SQL type maps to a Rust type, see the corresponding `types` module for each //! database: //! //! * [PostgreSQL](crate::postgres::types) //! * [MySQL](crate::mysql::types) //! * [SQLite](crate::sqlite::types) //! * [MSSQL](crate::mssql::types) //! //! Any external types that have had [`Type`] implemented for, are re-exported in this module //! for convenience as downstream users need to use a compatible version of the external crate //! to take advantage of the implementation. //! //! # Nullable //! //! To represent nullable SQL types, `Option<T>` is supported where `T` implements `Type`. //! An `Option<T>` represents a potentially `NULL` value from SQL. //! use crate::database::Database; #[cfg(feature = "bstr")] #[cfg_attr(docsrs, doc(cfg(feature = "bstr")))] pub mod bstr; #[cfg(feature = "git2")] #[cfg_attr(docsrs, doc(cfg(feature = "git2")))] pub mod git2; #[cfg(feature = "json")] #[cfg_attr(docsrs, doc(cfg(feature = "json")))] mod json; #[cfg(feature = "uuid")] #[cfg_attr(docsrs, doc(cfg(feature = "uuid")))] #[doc(no_inline)] pub use uuid::{self, Uuid}; #[cfg(feature = "chrono")] #[cfg_attr(docsrs, doc(cfg(feature = "chrono")))] pub mod chrono { #[doc(no_inline)] pub use chrono::{ DateTime, FixedOffset, Local, NaiveDate, NaiveDateTime, NaiveTime, TimeZone, Utc, }; } #[cfg(feature = "bit-vec")] #[cfg_attr(docsrs, doc(cfg(feature = "bit-vec")))] #[doc(no_inline)] pub use bit_vec::BitVec; #[cfg(feature = "time")] #[cfg_attr(docsrs, doc(cfg(feature = "time")))] pub mod time { #[doc(no_inline)] pub use time::{Date, OffsetDateTime, PrimitiveDateTime, Time, UtcOffset}; } #[cfg(feature = "bigdecimal")] #[cfg_attr(docsrs, doc(cfg(feature = "bigdecimal")))] #[doc(no_inline)] pub use bigdecimal::BigDecimal; #[cfg(feature = "decimal")] #[cfg_attr(docsrs, doc(cfg(feature = "decimal")))] #[doc(no_inline)] pub use rust_decimal::Decimal; #[cfg(feature = "ipnetwork")] #[cfg_attr(docsrs, doc(cfg(feature = "ipnetwork")))] pub mod ipnetwork { #[doc(no_inline)] pub use ipnetwork::{IpNetwork, Ipv4Network, Ipv6Network}; } #[cfg(feature = "json")] pub use json::Json; /// Indicates that a SQL type is supported for a database. /// /// ## Compile-time verification /// /// With compile-time verification, the use of type overrides is currently required to make /// use of any user-defined types. /// /// ```rust,ignore /// struct MyUser { id: UserId, name: String } /// /// // fetch all properties from user and override the type in Rust for `id` /// let user = query_as!(MyUser, r#"SELECT users.*, id as "id: UserId" FROM users"#) /// .fetch_one(&pool).await?; /// ``` /// /// ## Derivable /// /// This trait can be derived by SQLx to support Rust-only wrapper types, enumerations, and (for /// postgres) structured records. Additionally, an implementation of [`Encode`](crate::encode::Encode) and [`Decode`](crate::decode::Decode) is /// generated. /// /// ### Transparent /// /// Rust-only domain or wrappers around SQL types. The generated implementations directly delegate /// to the implementation of the inner type. /// /// ```rust,ignore /// #[derive(sqlx::Type)] /// #[sqlx(transparent)] /// struct UserId(i64); /// ``` /// /// ##### Attributes /// /// * `#[sqlx(type_name = "<SQL type name>")]` on struct definition: instead of inferring the SQL /// type name from the inner field (in the above case, `BIGINT`), explicitly set it to /// `<SQL type name>` instead. May trigger errors or unexpected behavior if the encoding of the /// given type is different than that of the inferred type (e.g. if you rename the above to /// `VARCHAR`). Affects Postgres only. /// * `#[sqlx(rename_all = "<strategy>")]` on struct definition: See [`derive docs in FromRow`](crate::from_row::FromRow#rename_all) /// /// ### Enumeration /// /// Enumerations may be defined in Rust and can match SQL by /// integer discriminant or variant name. /// /// With `#[repr(_)]` the integer representation is used when converting from/to SQL and expects /// that SQL type (e.g., `INT`). Without, the names of the variants are used instead and /// expects a textual SQL type (e.g., `VARCHAR`, `TEXT`). /// /// ```rust,ignore /// #[derive(sqlx::Type)] /// #[repr(i32)] /// enum Color { Red = 1, Green = 2, Blue = 3 } /// ``` /// /// ```rust,ignore /// #[derive(sqlx::Type)] /// #[sqlx(type_name = "color")] // only for PostgreSQL to match a type definition /// #[sqlx(rename_all = "lowercase")] /// enum Color { Red, Green, Blue } /// ``` /// /// ### Records /// /// User-defined composite types are supported through deriving a `struct`. /// /// This is only supported for PostgreSQL. /// /// ```rust,ignore /// #[derive(sqlx::Type)] /// #[sqlx(type_name = "interface_type")] /// struct InterfaceType { /// name: String, /// supplier_id: i32, /// price: f64 /// } /// ``` /// pub trait Type<DB: Database> { /// Returns the canonical SQL type for this Rust type. /// /// When binding arguments, this is used to tell the database what is about to be sent; which, /// the database then uses to guide query plans. This can be overridden by `Encode::produces`. /// /// A map of SQL types to Rust types is populated with this and used /// to determine the type that is returned from the anonymous struct type from `query!`. fn type_info() -> DB::TypeInfo; /// Determines if this Rust type is compatible with the given SQL type. /// /// When decoding values from a row, this method is checked to determine if we should continue /// or raise a runtime type mismatch error. /// /// When binding arguments with `query!` or `query_as!`, this method is consulted to determine /// if the Rust type is acceptable. fn compatible(ty: &DB::TypeInfo) -> bool { *ty == Self::type_info() } } // for references, the underlying SQL type is identical impl<T: ?Sized + Type<DB>, DB: Database> Type<DB> for &'_ T { fn type_info() -> DB::TypeInfo { <T as Type<DB>>::type_info() } fn compatible(ty: &DB::TypeInfo) -> bool { <T as Type<DB>>::compatible(ty) } } // for optionals, the underlying SQL type is identical impl<T: Type<DB>, DB: Database> Type<DB> for Option<T> { fn type_info() -> DB::TypeInfo { <T as Type<DB>>::type_info() } fn compatible(ty: &DB::TypeInfo) -> bool { <T as Type<DB>>::compatible(ty) } }