Struct SessionVariables 

pub struct SessionVariables { /* private fields */ }

Session-scoped user variables ($name).

A base store plus a transaction overlay: assignments made while an explicit transaction is active are recorded as operations instead of mutating the base store directly. COMMIT merges the overlay into the base store; ROLLBACK (and ROLLBACK TO SAVEPOINT) restores the base to its pre-transaction values.

Implementations

impl SessionVariables

pub fn new() -> Self

pub fn set_variable(&self, name: String, value: Value, in_transaction: bool)

Assign a session variable. When in_transaction is true, the assignment is recorded on the overlay instead of the base store so ROLLBACK / ROLLBACK TO SAVEPOINT restore the previous value.

pub fn variable_value(&self, name: &str) -> Option<Value>

Effective value of a session variable: transaction overlay first, then the base store.

pub fn variables_snapshot(&self) -> HashMap<String, Value>

Snapshot of all session variables (base + overlay) for injection as query inputs.

pub fn commit_variables(&self)

COMMIT: apply overlay operations to the base store and clear the overlay (the last assignment of each variable wins).

pub fn rollback_variables(&self)

Full ROLLBACK: restore pre-transaction values and clear the overlay.

pub fn rollback_variables_to(&self, savepoint_name: &str) -> bool

ROLLBACK TO SAVEPOINT: restore values assigned after the named savepoint and truncate the overlay at the savepoint marker.

pub fn release_variable_savepoint(&self, savepoint_name: &str)

RELEASE SAVEPOINT: drop the marker (operations stay part of the transaction; they are no longer individually rollback-able).

pub fn push_variable_savepoint(&self, savepoint_name: &str)

SAVEPOINT: record a variable-overlay boundary so ROLLBACK TO can restore assignments made after the savepoint.

Trait Implementations

impl Debug for SessionVariables

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

Formats the value using the given formatter.

impl Default for SessionVariables

fn default() -> Self

Returns the “default value” for a type.