Enum ReadLockMode 

#[non_exhaustive]
pub enum ReadLockMode {
    Unspecified,
    Pessimistic,
    Optimistic,
    UnknownValue(UnknownValue),
}

ReadLockMode is used to set the read lock mode for read-write transactions.

Working with unknown values

This enum is defined as #[non_exhaustive] because Google Cloud may add additional enum variants at any time. Adding new variants is not considered a breaking change. Applications should write their code in anticipation of:

• New values appearing in future releases of the client library, and
• New values received dynamically, without application changes.

Please consult the Working with enums section in the user guide for some guidelines.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Unspecified

Default value.

• If isolation level is SERIALIZABLE, locking semantics default to PESSIMISTIC.
• If isolation level is REPEATABLE_READ, locking semantics default to OPTIMISTIC.
• See Concurrency control for more details.

Pessimistic

Pessimistic lock mode.

Lock acquisition behavior depends on the isolation level in use. In SERIALIZABLE isolation, reads and writes acquire necessary locks during transaction statement execution. In REPEATABLE_READ isolation, reads that explicitly request to be locked and writes acquire locks. See Concurrency control for details on the types of locks acquired at each transaction step.

Optimistic

Optimistic lock mode.

Lock acquisition behavior depends on the isolation level in use. In both SERIALIZABLE and REPEATABLE_READ isolation, reads and writes do not acquire locks during transaction statement execution. See Concurrency control for details on how the guarantees of each isolation level are provided at commit time.

UnknownValue(UnknownValue)

If set, the enum was initialized with an unknown value.

Applications can examine the value using ReadLockMode::value or ReadLockMode::name.

Implementations

impl ReadLockMode

pub fn value(&self) -> Option<i32>

Gets the enum value.

Returns None if the enum contains an unknown value deserialized from the string representation of enums.

pub fn name(&self) -> Option<&str>

Gets the enum value as a string.

Returns None if the enum contains an unknown value deserialized from the integer representation of enums.

Trait Implementations

impl Clone for ReadLockMode

fn clone(&self) -> ReadLockMode

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ReadLockMode

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for ReadLockMode

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for ReadLockMode

fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Display for ReadLockMode

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl From<&str> for ReadLockMode

fn from(value: &str) -> Self

Converts to this type from the input type.

impl From<i32> for ReadLockMode

fn from(value: i32) -> Self

Converts to this type from the input type.

impl PartialEq for ReadLockMode

fn eq(&self, other: &ReadLockMode) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for ReadLockMode

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for ReadLockMode