Trait sqlx_core::decode::Decode

pub trait Decode<'r, DB: Database>: Sized {
    // Required method
    fn decode(
        value: <DB as HasValueRef<'r>>::ValueRef
    ) -> Result<Self, BoxDynError>;
}

A type that can be decoded from the database.

How can I implement Decode?

A manual implementation of Decode can be useful when adding support for types externally to SQLx.

The following showcases how to implement Decode to be generic over Database. The implementation can be marginally simpler if you remove the DB type parameter and explicitly use the concrete ValueRef and TypeInfo types.

struct MyType;

// DB is the database driver
// `'r` is the lifetime of the `Row` being decoded
impl<'r, DB: Database> Decode<'r, DB> for MyType
where
    // we want to delegate some of the work to string decoding so let's make sure strings
    // are supported by the database
    &'r str: Decode<'r, DB>
{
    fn decode(
        value: <DB as HasValueRef<'r>>::ValueRef,
    ) -> Result<MyType, Box<dyn Error + 'static + Send + Sync>> {
        // the interface of ValueRef is largely unstable at the moment
        // so this is not directly implementable

        // however, you can delegate to a type that matches the format of the type you want
        // to decode (such as a UTF-8 string)

        let value = <&str as Decode<DB>>::decode(value)?;

        // now you can parse this into your type (assuming there is a `FromStr`)

        Ok(value.parse()?)
    }
}

Required Methods

fn decode(value: <DB as HasValueRef<'r>>::ValueRef) -> Result<Self, BoxDynError>

Decode a new value of this type using a raw value from the database.

Implementations on Foreign Types

impl<'r> Decode<'r, MySql> for DateTime<Utc>

Note: assumes the connection’s time_zone is set to +00:00 (UTC).

fn decode(value: MySqlValueRef<'r>) -> Result<Self, BoxDynError>

impl Decode<'_, Postgres> for f32

fn decode(value: PgValueRef<'_>) -> Result<Self, BoxDynError>

impl Decode<'_, Postgres> for BigDecimal

fn decode(value: PgValueRef<'_>) -> Result<Self, BoxDynError>

impl Decode<'_, Mssql> for String

fn decode(value: MssqlValueRef<'_>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, MySql> for NaiveDate

fn decode(value: MySqlValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Sqlite> for DateTime<Utc>

fn decode(value: SqliteValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, MySql> for &'r str

fn decode(value: MySqlValueRef<'r>) -> Result<Self, BoxDynError>

impl Decode<'_, MySql> for BigDecimal

fn decode(value: MySqlValueRef<'_>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Postgres> for NaiveDateTime

fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Any> for f32where f32: AnyDecode<'r>,

fn decode(value: AnyValueRef<'r>) -> Result<Self, BoxDynError>

impl<const N: usize> Decode<'_, Postgres> for [u8; N]

fn decode(value: PgValueRef<'_>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Sqlite> for DateTime<Local>

fn decode(value: SqliteValueRef<'r>) -> Result<Self, BoxDynError>

impl Decode<'_, Mssql> for f32

fn decode(value: MssqlValueRef<'_>) -> Result<Self, BoxDynError>

impl Decode<'_, MySql> for u8

fn decode(value: MySqlValueRef<'_>) -> Result<Self, BoxDynError>

impl<'db> Decode<'db, Postgres> for IpAddrwhere IpNetwork: Decode<'db, Postgres>,

fn decode(value: PgValueRef<'db>) -> Result<Self, BoxDynError>

impl Decode<'_, MySql> for Uuid

fn decode(value: MySqlValueRef<'_>) -> Result<Self, BoxDynError>

impl<'r, T, const N: usize> Decode<'r, Postgres> for [T; N]where T: for<'a> Decode<'a, Postgres> + Type<Postgres>,

fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError>

impl Decode<'_, Mssql> for f64

fn decode(value: MssqlValueRef<'_>) -> Result<Self, BoxDynError>

impl Decode<'_, MySql> for String

fn decode(value: MySqlValueRef<'_>) -> Result<Self, BoxDynError>

impl Decode<'_, MySql> for u32

fn decode(value: MySqlValueRef<'_>) -> Result<Self, BoxDynError>

impl Decode<'_, Postgres> for Uuid

fn decode(value: PgValueRef<'_>) -> Result<Self, BoxDynError>

impl Decode<'_, MySql> for i8

fn decode(value: MySqlValueRef<'_>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, MySql> for Cow<'r, str>

fn decode(value: MySqlValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Any> for f64where f64: AnyDecode<'r>,

fn decode(value: AnyValueRef<'r>) -> Result<Self, BoxDynError>

impl Decode<'_, Mssql> for u8

fn decode(value: MssqlValueRef<'_>) -> Result<Self, BoxDynError>

impl Decode<'_, MySql> for u64

fn decode(value: MySqlValueRef<'_>) -> Result<Self, BoxDynError>

impl Decode<'_, MySql> for i32

fn decode(value: MySqlValueRef<'_>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Sqlite> for i32

fn decode(value: SqliteValueRef<'r>) -> Result<Self, BoxDynError>

impl Decode<'_, Mssql> for i64

fn decode(value: MssqlValueRef<'_>) -> Result<Self, BoxDynError>

impl<'r, T1, T2, T3> Decode<'r, Postgres> for (T1, T2, T3)where T1: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T2: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T3: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>,

fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Sqlite> for i8

fn decode(value: SqliteValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Sqlite> for NaiveTime

fn decode(value: SqliteValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Sqlite> for i16

fn decode(value: SqliteValueRef<'r>) -> Result<Self, BoxDynError>

impl Decode<'_, Postgres> for IpNetwork

fn decode(value: PgValueRef<'_>) -> Result<Self, BoxDynError>

impl Decode<'_, Postgres> for MacAddress

fn decode(value: PgValueRef<'_>) -> Result<Self, BoxDynError>

impl Decode<'_, Sqlite> for Uuid

fn decode(value: SqliteValueRef<'_>) -> Result<Self, BoxDynError>

impl Decode<'_, MySql> for bool

fn decode(value: MySqlValueRef<'_>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Sqlite> for u8

fn decode(value: SqliteValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Sqlite> for &'r [u8]

fn decode(value: SqliteValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Sqlite> for NaiveDateTime

fn decode(value: SqliteValueRef<'r>) -> Result<Self, BoxDynError>

impl Decode<'_, MySql> for i64

fn decode(value: MySqlValueRef<'_>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Postgres> for ()

fn decode(_value: PgValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, MySql> for NaiveTime

fn decode(value: MySqlValueRef<'r>) -> Result<Self, BoxDynError>

impl Decode<'_, MySql> for f64

fn decode(value: MySqlValueRef<'_>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Sqlite> for String

fn decode(value: SqliteValueRef<'r>) -> Result<Self, BoxDynError>

impl Decode<'_, Postgres> for bool

fn decode(value: PgValueRef<'_>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Sqlite> for Vec<u8>

fn decode(value: SqliteValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Any> for i32where i32: AnyDecode<'r>,

fn decode(value: AnyValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r, T1, T2> Decode<'r, Postgres> for (T1, T2)where T1: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T2: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>,

fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r, T1, T2, T3, T4, T5, T6, T7> Decode<'r, Postgres> for (T1, T2, T3, T4, T5, T6, T7)where T1: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T2: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T3: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T4: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T5: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T6: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T7: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>,

fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Postgres> for Time

fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Sqlite> for OffsetDateTime

fn decode(value: SqliteValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r, T> Decode<'r, Postgres> for Vec<T>where T: for<'a> Decode<'a, Postgres> + Type<Postgres>,

fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, MySql> for Date

fn decode(value: MySqlValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Sqlite> for u32

fn decode(value: SqliteValueRef<'r>) -> Result<Self, BoxDynError>

impl Decode<'_, MySql> for Hyphenated

fn decode(value: MySqlValueRef<'_>) -> Result<Self, BoxDynError>

impl<'r, T1, T2, T3, T4, T5, T6> Decode<'r, Postgres> for (T1, T2, T3, T4, T5, T6)where T1: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T2: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T3: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T4: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T5: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T6: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>,

fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError>

impl Decode<'_, MySql> for i16

fn decode(value: MySqlValueRef<'_>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Sqlite> for Cow<'r, str>

fn decode(value: SqliteValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Postgres> for Cow<'r, str>

fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError>

impl Decode<'_, Mssql> for i32

fn decode(value: MssqlValueRef<'_>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Sqlite> for f64

fn decode(value: SqliteValueRef<'r>) -> Result<f64, BoxDynError>

impl<'r> Decode<'r, MySql> for NaiveDateTime

fn decode(value: MySqlValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Postgres> for Date

fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError>

impl Decode<'_, Postgres> for i32

fn decode(value: PgValueRef<'_>) -> Result<Self, BoxDynError>

impl Decode<'_, Postgres> for String

fn decode(value: PgValueRef<'_>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, MySql> for &'r [u8]

fn decode(value: MySqlValueRef<'r>) -> Result<Self, BoxDynError>

impl Decode<'_, Mssql> for bool

fn decode(value: MssqlValueRef<'_>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Postgres> for NaiveTime

fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Postgres> for &'r str

fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, MySql> for PrimitiveDateTime

fn decode(value: MySqlValueRef<'r>) -> Result<Self, BoxDynError>

impl Decode<'_, Postgres> for Decimal

fn decode(value: PgValueRef<'_>) -> Result<Self, BoxDynError>

impl Decode<'_, Postgres> for BitVec

fn decode(value: PgValueRef<'_>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Any> for i16where i16: AnyDecode<'r>,

fn decode(value: AnyValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Postgres> for OffsetDateTime

fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Sqlite> for bool

fn decode(value: SqliteValueRef<'r>) -> Result<bool, BoxDynError>

impl<'r> Decode<'r, Any> for boolwhere bool: AnyDecode<'r>,

fn decode(value: AnyValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Sqlite> for u16

fn decode(value: SqliteValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, MySql> for OffsetDateTime

fn decode(value: MySqlValueRef<'r>) -> Result<Self, BoxDynError>

impl Decode<'_, MySql> for f32

fn decode(value: MySqlValueRef<'_>) -> Result<Self, BoxDynError>

impl<'r, T1, T2, T3, T4, T5, T6, T7, T8, T9> Decode<'r, Postgres> for (T1, T2, T3, T4, T5, T6, T7, T8, T9)where T1: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T2: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T3: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T4: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T5: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T6: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T7: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T8: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T9: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>,

fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Sqlite> for DateTime<FixedOffset>

fn decode(value: SqliteValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Sqlite> for i64

fn decode(value: SqliteValueRef<'r>) -> Result<Self, BoxDynError>

impl Decode<'_, Mssql> for i16

fn decode(value: MssqlValueRef<'_>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, MySql> for Time

fn decode(value: MySqlValueRef<'r>) -> Result<Self, BoxDynError>

impl Decode<'_, Postgres> for f64

fn decode(value: PgValueRef<'_>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Postgres> for NaiveDate

fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Sqlite> for f32

fn decode(value: SqliteValueRef<'r>) -> Result<f32, BoxDynError>

impl<'r> Decode<'r, Sqlite> for Time

fn decode(value: SqliteValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Sqlite> for NaiveDate

fn decode(value: SqliteValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Postgres> for DateTime<Utc>

fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError>

impl Decode<'_, Postgres> for i64

fn decode(value: PgValueRef<'_>) -> Result<Self, BoxDynError>

impl Decode<'_, Postgres> for Vec<u8>

fn decode(value: PgValueRef<'_>) -> Result<Self, BoxDynError>

impl<'r, T1, T2, T3, T4, T5> Decode<'r, Postgres> for (T1, T2, T3, T4, T5)where T1: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T2: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T3: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T4: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T5: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>,

fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Sqlite> for PrimitiveDateTime

fn decode(value: SqliteValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Sqlite> for Date

fn decode(value: SqliteValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r, T1, T2, T3, T4> Decode<'r, Postgres> for (T1, T2, T3, T4)where T1: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T2: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T3: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T4: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>,

fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Sqlite> for &'r str

fn decode(value: SqliteValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Any> for Stringwhere String: AnyDecode<'r>,

fn decode(value: AnyValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Postgres> for DateTime<FixedOffset>

fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError>

impl Decode<'_, MySql> for u16

fn decode(value: MySqlValueRef<'_>) -> Result<Self, BoxDynError>

impl Decode<'_, Sqlite> for Hyphenated

fn decode(value: SqliteValueRef<'_>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Mssql> for Cow<'r, str>

fn decode(value: MssqlValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r, T1, T2, T3, T4, T5, T6, T7, T8> Decode<'r, Postgres> for (T1, T2, T3, T4, T5, T6, T7, T8)where T1: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T2: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T3: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T4: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T5: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T6: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T7: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>, T8: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>,

fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError>

impl Decode<'_, MySql> for Vec<u8>

fn decode(value: MySqlValueRef<'_>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Any> for &'r strwhere &'r str: AnyDecode<'r>,

fn decode(value: AnyValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Postgres> for PrimitiveDateTime

fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Any> for i64where i64: AnyDecode<'r>,

fn decode(value: AnyValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Postgres> for &'r [u8]

fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError>

impl Decode<'_, Postgres> for i8

fn decode(value: PgValueRef<'_>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, Postgres> for DateTime<Local>

fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r, T1> Decode<'r, Postgres> for (T1,)where T1: 'r + Type<Postgres> + for<'a> Decode<'a, Postgres>,

fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError>

impl Decode<'_, Postgres> for i16

fn decode(value: PgValueRef<'_>) -> Result<Self, BoxDynError>

impl<'r> Decode<'r, MySql> for DateTime<Local>

Note: assumes the connection’s time_zone is set to +00:00 (UTC).

fn decode(value: MySqlValueRef<'r>) -> Result<Self, BoxDynError>

impl<'r, DB, T> Decode<'r, DB> for Option<T>where DB: Database, T: Decode<'r, DB>,

fn decode(value: <DB as HasValueRef<'r>>::ValueRef) -> Result<Self, BoxDynError>

impl Decode<'_, MySql> for Decimal

fn decode(value: MySqlValueRef<'_>) -> Result<Self, BoxDynError>

impl Decode<'_, Mssql> for i8

fn decode(value: MssqlValueRef<'_>) -> Result<Self, BoxDynError>

Implementors

impl Decode<'_, Postgres> for Oid

impl Decode<'_, Postgres> for PgMoney

impl<'de> Decode<'de, Postgres> for PgInterval

impl<'r> Decode<'r, Postgres> for PgLQuery

impl<'r> Decode<'r, Postgres> for PgLTree

impl<'r> Decode<'r, Postgres> for PgTimeTz<NaiveTime, FixedOffset>

impl<'r> Decode<'r, Postgres> for PgTimeTz<Time, UtcOffset>

impl<'r, DB> Decode<'r, DB> for &'r JsonRawValuewhere Json<Self>: Decode<'r, DB>, DB: Database,

impl<'r, DB> Decode<'r, DB> for JsonValuewhere Json<Self>: Decode<'r, DB>, DB: Database,

impl<'r, T> Decode<'r, MySql> for Json<T>where T: 'r + Deserialize<'r>,

impl<'r, T> Decode<'r, Postgres> for PgRange<T>where T: Type<Postgres> + for<'a> Decode<'a, Postgres>,

impl<'r, T> Decode<'r, Postgres> for Json<T>where T: Deserialize<'r> + 'r,

impl<'r, T> Decode<'r, Sqlite> for Json<T>where T: 'r + Deserialize<'r>,