Trait postgres::types::FromSql
[−]
[src]
pub trait FromSql: Sized { fn from_sql<R: Read>(ty: &Type, raw: &mut R, ctx: &SessionInfo) -> Result<Self>; fn accepts(ty: &Type) -> bool; fn from_sql_nullable<R: Read>(ty: &Type, raw: Option<&mut R>, ctx: &SessionInfo) -> Result<Self> { ... } }
A trait for types that can be created from a Postgres value.
Types
The following implementations are provided by this crate, along with the corresponding Postgres types:
Rust type | Postgres type(s) |
---|---|
bool | BOOL |
i8 | "char" |
i16 | SMALLINT, SMALLSERIAL |
i32 | INT, SERIAL |
u32 | OID |
i64 | BIGINT, BIGSERIAL |
f32 | REAL |
f64 | DOUBLE PRECISION |
String | VARCHAR, CHAR(n), TEXT, CITEXT |
Vec<u8> | BYTEA |
HashMap<String, Option<String>> | HSTORE |
In addition, some implementations are provided for types in third party
crates. These are disabled by default; to opt into one of these
implementations, activate the Cargo feature corresponding to the crate's
name. For example, the serde
feature enables the implementation for the
serde::json::Value
type.
Rust type | Postgres type(s) |
---|---|
serialize::json::Json | JSON, JSONB |
serde::json::Value | JSON, JSONB |
time::Timespec | TIMESTAMP, TIMESTAMP WITH TIME ZONE |
chrono::NaiveDateTime | TIMESTAMP |
chrono::DateTime<UTC> | TIMESTAMP WITH TIME ZONE |
chrono::NaiveDate | DATE |
chrono::NaiveTime | TIME |
uuid::Uuid | UUID |
Nullability
In addition to the types listed above, FromSql
is implemented for
Option<T>
where T
implements FromSql
. An Option<T>
represents a
nullable Postgres value.
Required Methods
fn from_sql<R: Read>(ty: &Type, raw: &mut R, ctx: &SessionInfo) -> Result<Self>
Creates a new value of this type from a Read
er of the binary format
of the specified Postgres Type
.
The caller of this method is responsible for ensuring that this type
is compatible with the Postgres Type
.
fn accepts(ty: &Type) -> bool
Determines if a value of this type can be created from the specified
Postgres Type
.
Provided Methods
fn from_sql_nullable<R: Read>(ty: &Type, raw: Option<&mut R>, ctx: &SessionInfo) -> Result<Self>
Creates a new value of this type from a Read
of Postgres data.
If the value was NULL
, the Read
will be None
.
The caller of this method is responsible for ensuring that this type
is compatible with the Postgres Type
.
The default implementation calls FromSql::from_sql
when raw
is
Some
and returns Err(Error::Conversion(Box::new(WasNull))
when
raw
is None
. It does not typically need to be overridden.
Implementors
impl<T: FromSql> FromSql for Option<T>
impl FromSql for bool
impl FromSql for Vec<u8>
impl FromSql for String
impl FromSql for i8
impl FromSql for i16
impl FromSql for i32
impl FromSql for u32
impl FromSql for i64
impl FromSql for f32
impl FromSql for f64
impl FromSql for HashMap<String, Option<String>>