Struct qldb::Cursor

pub struct Cursor { /* private fields */ }

Cursor allows to get all values from a statement page by page.

QLDB returns 200 documents for each page.

You don’t need to directly use Cursor in your code. When the method uses Cursor internally in order to load all values.

use qldb::{QldbClient, Cursor};

let client = QldbClient::default("rust-crate-test", 200).await?;

let mut value_to_insert = HashMap::new();
// This will insert a documents with a key "test_column"
// with the value "IonValue::String(test_value)"
value_to_insert.insert("test_column", "test_value");

client
    .transaction_within(|client| async move {   
        let mut cursor = client
            .query("SEL/CT * FROM TestTable")
            .get_cursor()?;
             
            while let Some(mut values) = cursor.load_more().await? {
                println!("{:?}", values);
            }

        Ok(())
    })
    .await?;

Implementations

impl Cursor

pub async fn load_more(&mut self) -> QldbResult<Option<DocumentCollection>>

It loads the next page from a query. It automatically tracks the next_page_token, so you can call this method again and again in order to load all pages.

It returns Ok(Some(_)) when QLDB returns documents.

It returns Ok(None) when QLDB doesn’t return documents, which means that there isn’t more pages to query

    while let Some(mut values) = cursor.load_more().await? {
        println!("{:?}", values);
    }
     

pub async fn load_all(self) -> QldbResult<DocumentCollection>

Loads all pages from the cursor and consumes it in the process.

Trait Implementations

impl Debug for Cursor

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

Formats the value using the given formatter.