#[non_exhaustive]pub enum TargetDatabaseEngine {
AwsPostgresql,
AmazonAurora,
Db2Luw,
MariaDb,
MicrosoftSqlServer,
MongoDb,
Mysql,
NoneSpecified,
OracleDatabase,
Sap,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against TargetDatabaseEngine
, it is important to ensure
your code is forward-compatible. That is, if a match arm handles a case for a
feature that is supported by the service but has not been represented as an enum
variant in a current version of SDK, your code should continue to work when you
upgrade SDK to a future version in which the enum does include a variant for that
feature.
Here is an example of how you can make a match expression forward-compatible:
# let targetdatabaseengine = unimplemented!();
match targetdatabaseengine {
TargetDatabaseEngine::AwsPostgresql => { /* ... */ },
TargetDatabaseEngine::AmazonAurora => { /* ... */ },
TargetDatabaseEngine::Db2Luw => { /* ... */ },
TargetDatabaseEngine::MariaDb => { /* ... */ },
TargetDatabaseEngine::MicrosoftSqlServer => { /* ... */ },
TargetDatabaseEngine::MongoDb => { /* ... */ },
TargetDatabaseEngine::Mysql => { /* ... */ },
TargetDatabaseEngine::NoneSpecified => { /* ... */ },
TargetDatabaseEngine::OracleDatabase => { /* ... */ },
TargetDatabaseEngine::Sap => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when targetdatabaseengine
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant TargetDatabaseEngine::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
TargetDatabaseEngine::Unknown(UnknownVariantValue("NewFeature".to_owned()))
and calling as_str
on it yields "NewFeature"
.
This match expression is forward-compatible when executed with a newer
version of SDK where the variant TargetDatabaseEngine::NewFeature
is defined.
Specifically, when targetdatabaseengine
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on TargetDatabaseEngine::NewFeature
also yielding "NewFeature"
.
Explicitly matching on the Unknown
variant should
be avoided for two reasons:
- The inner data
UnknownVariantValue
is opaque, and no further information can be extracted. - It might inadvertently shadow other intended match arms.
Variants (Non-exhaustive)§
This enum is marked as non-exhaustive
AwsPostgresql
AmazonAurora
Db2Luw
MariaDb
MicrosoftSqlServer
MongoDb
Mysql
NoneSpecified
OracleDatabase
Sap
Unknown(UnknownVariantValue)
Unknown
. See the docs on this enum for the correct way to handle unknown variants.Unknown
contains new variants that have been added since this code was generated.
Implementations§
source§impl TargetDatabaseEngine
impl TargetDatabaseEngine
sourcepub fn try_parse(value: &str) -> Result<Self, UnknownVariantError>
pub fn try_parse(value: &str) -> Result<Self, UnknownVariantError>
Parses the enum value while disallowing unknown variants.
Unknown variants will result in an error.
Trait Implementations§
source§impl AsRef<str> for TargetDatabaseEngine
impl AsRef<str> for TargetDatabaseEngine
source§impl Clone for TargetDatabaseEngine
impl Clone for TargetDatabaseEngine
source§fn clone(&self) -> TargetDatabaseEngine
fn clone(&self) -> TargetDatabaseEngine
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for TargetDatabaseEngine
impl Debug for TargetDatabaseEngine
source§impl Display for TargetDatabaseEngine
impl Display for TargetDatabaseEngine
source§impl From<&str> for TargetDatabaseEngine
impl From<&str> for TargetDatabaseEngine
source§impl FromStr for TargetDatabaseEngine
impl FromStr for TargetDatabaseEngine
source§impl Hash for TargetDatabaseEngine
impl Hash for TargetDatabaseEngine
source§impl Ord for TargetDatabaseEngine
impl Ord for TargetDatabaseEngine
source§fn cmp(&self, other: &TargetDatabaseEngine) -> Ordering
fn cmp(&self, other: &TargetDatabaseEngine) -> Ordering
1.21.0 · source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere
Self: Sized,
source§impl PartialEq for TargetDatabaseEngine
impl PartialEq for TargetDatabaseEngine
source§fn eq(&self, other: &TargetDatabaseEngine) -> bool
fn eq(&self, other: &TargetDatabaseEngine) -> bool
self
and other
values to be equal, and is used
by ==
.source§impl PartialOrd for TargetDatabaseEngine
impl PartialOrd for TargetDatabaseEngine
source§fn partial_cmp(&self, other: &TargetDatabaseEngine) -> Option<Ordering>
fn partial_cmp(&self, other: &TargetDatabaseEngine) -> Option<Ordering>
1.0.0 · source§fn le(&self, other: &Rhs) -> bool
fn le(&self, other: &Rhs) -> bool
self
and other
) and is used by the <=
operator. Read moreimpl Eq for TargetDatabaseEngine
impl StructuralPartialEq for TargetDatabaseEngine
Auto Trait Implementations§
impl Freeze for TargetDatabaseEngine
impl RefUnwindSafe for TargetDatabaseEngine
impl Send for TargetDatabaseEngine
impl Sync for TargetDatabaseEngine
impl Unpin for TargetDatabaseEngine
impl UnwindSafe for TargetDatabaseEngine
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
source§impl<Q, K> Comparable<K> for Q
impl<Q, K> Comparable<K> for Q
source§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
source§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
source§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key
and return true
if they are equal.source§impl<T> Instrument for T
impl<T> Instrument for T
source§fn instrument(self, span: Span) -> Instrumented<Self>
fn instrument(self, span: Span) -> Instrumented<Self>
source§fn in_current_span(self) -> Instrumented<Self>
fn in_current_span(self) -> Instrumented<Self>
source§impl<T> IntoEither for T
impl<T> IntoEither for T
source§fn into_either(self, into_left: bool) -> Either<Self, Self>
fn into_either(self, into_left: bool) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left
is true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read moresource§fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left(&self)
returns true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read more