Enum TransactionIsolation 

pub enum TransactionIsolation {
    ReadUncommitted,
    ReadCommitted,
    RepeatableRead,
    Serializable,
}

SQL 事务隔离级别。

对应 SQL 标准的四种隔离级别，不同后端的 SQL 语法略有差异。

Variants

ReadUncommitted

读未提交（最低隔离级别，允许脏读）

ReadCommitted

读已提交（禁止脏读，允许不可重复读）

RepeatableRead

可重复读（禁止不可重复读，允许幻读）

Serializable

串行化（最高隔离级别，完全隔离）

Implementations

impl TransactionIsolation

pub fn name(&self) -> &'static str

返回隔离级别的标准名称。

pub fn description(&self) -> &'static str

返回隔离级别的中文描述。

pub fn strictness(&self) -> u8

返回隔离级别的严格程度排序值（0=最低，3=最高）。

pub fn set_session_sql(&self, backend: AnyBackend) -> String

生成设置当前会话隔离级别的 SQL 语句。

不同后端语法略有差异：

• MySQL: SET SESSION TRANSACTION ISOLATION LEVEL READ COMMITTED
• PostgreSQL: SET SESSION CHARACTERISTICS AS TRANSACTION ISOLATION LEVEL READ COMMITTED
• SQLite: 不支持（SQLite 始终使用 SERIALIZABLE），返回空字符串

pub fn set_transaction_sql(&self, backend: AnyBackend) -> String

生成设置下一事务隔离级别的 SQL 语句。

• MySQL: SET TRANSACTION ISOLATION LEVEL READ COMMITTED
• PostgreSQL: SET TRANSACTION ISOLATION LEVEL READ COMMITTED
• SQLite: 不支持，返回空字符串

pub fn query_sql(&self, backend: AnyBackend) -> String

生成查询当前隔离级别的 SQL 语句。

• MySQL: SELECT @@transaction_isolation
• PostgreSQL: SHOW transaction_isolation
• SQLite: 不支持，返回空字符串

pub fn from_str(s: &str) -> Option<Self>

从字符串解析隔离级别（不区分大小写）。

Trait Implementations

impl Clone for TransactionIsolation

fn clone(&self) -> TransactionIsolation

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for TransactionIsolation

impl Debug for TransactionIsolation

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

Formats the value using the given formatter.

impl Default for TransactionIsolation

fn default() -> TransactionIsolation

Returns the “default value” for a type.

impl Display for TransactionIsolation

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

Formats the value using the given formatter.

impl Eq for TransactionIsolation

impl Hash for TransactionIsolation

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for TransactionIsolation

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for TransactionIsolation