Trait sqlx_core::decode::Decode

pub trait Decode<'r, DB: Database>: Sized {
    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, 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<'r, DB> Decode<'r, DB> for JsonValue where
    Json<Self>: Decode<'r, DB>,
    DB: Database, 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

fn decode(value: AnyValueRef<'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 Decode<'_, Postgres> for bool

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

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

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

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

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

impl Decode<'_, Postgres> for f32

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

impl Decode<'_, Postgres> for f64

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

impl Decode<'_, Postgres> for i8

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

impl Decode<'_, Postgres> for i16

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

impl Decode<'_, Postgres> for u32

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

impl Decode<'_, Postgres> for i32

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

impl Decode<'_, Postgres> for i64

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

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

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

impl Decode<'_, Postgres> for String

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

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

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

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

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

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

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

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

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

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

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

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

fn decode(value: PgValueRef<'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,
    T2: 'r,
    T3: 'r,
    T4: 'r,
    T5: 'r,
    T6: 'r,
    T7: 'r,
    T8: 'r,
    T1: Type<Postgres>,
    T2: Type<Postgres>,
    T3: Type<Postgres>,
    T4: Type<Postgres>,
    T5: Type<Postgres>,
    T6: Type<Postgres>,
    T7: Type<Postgres>,
    T8: Type<Postgres>,
    T1: for<'a> Decode<'a, Postgres>,
    T2: for<'a> Decode<'a, Postgres>,
    T3: for<'a> Decode<'a, Postgres>,
    T4: for<'a> Decode<'a, Postgres>,
    T5: for<'a> Decode<'a, Postgres>,
    T6: for<'a> Decode<'a, Postgres>,
    T7: for<'a> Decode<'a, Postgres>,
    T8: for<'a> Decode<'a, Postgres>, 

fn decode(value: PgValueRef<'r>) -> 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,
    T2: 'r,
    T3: 'r,
    T4: 'r,
    T5: 'r,
    T6: 'r,
    T7: 'r,
    T8: 'r,
    T9: 'r,
    T1: Type<Postgres>,
    T2: Type<Postgres>,
    T3: Type<Postgres>,
    T4: Type<Postgres>,
    T5: Type<Postgres>,
    T6: Type<Postgres>,
    T7: Type<Postgres>,
    T8: Type<Postgres>,
    T9: Type<Postgres>,
    T1: for<'a> Decode<'a, Postgres>,
    T2: for<'a> Decode<'a, Postgres>,
    T3: for<'a> Decode<'a, Postgres>,
    T4: for<'a> Decode<'a, Postgres>,
    T5: for<'a> Decode<'a, Postgres>,
    T6: for<'a> Decode<'a, Postgres>,
    T7: for<'a> Decode<'a, Postgres>,
    T8: for<'a> Decode<'a, Postgres>,
    T9: for<'a> Decode<'a, Postgres>, 

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

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

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

impl Decode<'_, Postgres> for BigDecimal

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

impl Decode<'_, Postgres> for Decimal

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, Postgres> for NaiveDateTime

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

impl Decode<'_, Postgres> for Uuid

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

impl Decode<'_, Postgres> for IpNetwork

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

impl Decode<'_, Postgres> for BitVec

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

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

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

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

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

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

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

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

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

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

fn decode(value: SqliteValueRef<'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 NaiveDateTime

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, Sqlite> for NaiveTime

fn decode(value: SqliteValueRef<'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 f64

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

impl Decode<'_, Sqlite> for Uuid

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

impl Decode<'_, Sqlite> for Hyphenated

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

impl Decode<'_, MySql> for bool

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

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

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

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

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

impl Decode<'_, MySql> for f32

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

impl Decode<'_, MySql> for f64

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

impl Decode<'_, MySql> for i8

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

impl Decode<'_, MySql> for i16

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

impl Decode<'_, MySql> for i32

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

impl Decode<'_, MySql> for i64

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

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

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

impl Decode<'_, MySql> for String

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

impl Decode<'_, MySql> for u8

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

impl Decode<'_, MySql> for u16

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

impl Decode<'_, MySql> for u32

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

impl Decode<'_, MySql> for u64

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

impl Decode<'_, MySql> for BigDecimal

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

impl Decode<'_, MySql> for Decimal

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

impl Decode<'_, MySql> for Uuid

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

impl Decode<'_, MySql> for Hyphenated

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

impl Decode<'_, Mssql> for bool

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

impl Decode<'_, Mssql> for f32

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

impl Decode<'_, Mssql> for f64

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

impl Decode<'_, Mssql> for i8

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

impl Decode<'_, Mssql> for i16

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

impl Decode<'_, Mssql> for i32

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

impl Decode<'_, Mssql> for i64

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

impl Decode<'_, Mssql> for String

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

Implementors

impl Decode<'_, Postgres> for PgMoney

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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