Struct ReadWriteTransaction

Source

pub struct ReadWriteTransaction { /* private fields */ }

Expand description

A read-write transaction.

Implementations§

Source §

impl ReadWriteTransaction

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pub fn buffer(&self, mutations: I) -> Result<()>
where I: IntoIterator<Item = Mutation>,

Buffers one or more mutations to be applied when the transaction commits.

§Example

let db_client = spanner.database_client("projects/p/instances/i/databases/d").build().await?;
let runner = db_client.read_write_transaction().build().await?;
runner.run(async |tx| {
    let mutation = Mutation::new_insert_builder("users")
        .set("id").to(&1)
        .build();
    tx.buffer([mutation])?;
    Ok(())
}).await?;

Source

pub async fn execute_query<T: Into<Statement>>( &self, statement: T, ) -> Result<ResultSet>

Executes a query using this transaction.

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pub async fn execute_read<T: Into<ReadRequest>>( &self, read: T, ) -> Result<ResultSet>

Reads rows from the database using key lookups and scans, as a simple key/value style alternative to execute_query.

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pub async fn execute_update<T: Into<Statement>>( &self, statement: T, ) -> Result<i64>

Executes an update using this transaction.

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pub async fn execute_batch_update<T: Into<BatchDml>>( &self, batch: T, ) -> Result<Vec<i64>>

Executes a batch of DML statements using this transaction.

§Example

let db_client = spanner.database_client("projects/p/instances/i/databases/d").build().await?;
let runner = db_client.read_write_transaction().build().await?;
let result = runner.run(async |transaction| {
    let statement1 = Statement::builder("UPDATE users SET active = true WHERE id = @id")
        .add_param("id", &1)
        .build();
    let statement2 = Statement::builder("UPDATE users SET active = true WHERE id = @id")
        .add_param("id", &2)
        .build();
    let batch = BatchDml::builder()
        .add_statement(statement1)
        .add_statement(statement2)
        .build();
    let update_counts = transaction.execute_batch_update(batch).await?;
    Ok(())
}).await?;

If a BatchDml request fails halfway through execution, execute_batch_update will return a BatchUpdateError indicating exactly which statements succeeded (and their respective update counts) before the batch execution failed.

§Error Handling Example

let statement1 = Statement::builder("UPDATE users SET active = true WHERE id = 1").build();
let statement2 = Statement::builder("UPDATE non_existent_table SET active = true WHERE id = 2").build();

let batch = BatchDml::builder()
    .add_statement(statement1)
    .add_statement(statement2)
    .build();

match transaction.execute_batch_update(batch).await {
    Ok(update_counts) => {
        println!("All statements succeeded. Update counts: {:?}", update_counts);
    }
    Err(e) => {
        if let Some(batch_error) = BatchUpdateError::extract(&e) {
            println!("Batch execution failed. Successful update counts: {:?}", batch_error.update_counts);
        } else {
            println!("RPC failed or internal error occurred: {}", e);
        }
    }
}