Struct odbc_api::RowSetCursor

pub struct RowSetCursor<C: AsStatementRef, B> { /* private fields */ }

Iterates in blocks (called row sets) over a result set, filling a buffers with a lot of rows at once, instead of iterating the result set row by row. This is usually much faster.

Implementations

impl<C, B> RowSetCursor<C, B>where
    C: Cursor,

pub fn fetch(&mut self) -> Result<Option<&B>, Error>

Fills the bound buffer with the next row set.

Return

None if the result set is empty and all row sets have been extracted. Some with a reference to the internal buffer otherwise.

use odbc_api::{buffers::TextRowSet, Cursor};

fn print_all_values(mut cursor: impl Cursor) {
    let batch_size = 100;
    let max_string_len = 4000;
    let buffer = TextRowSet::for_cursor(batch_size, &mut cursor, Some(4000)).unwrap();
    let mut cursor = cursor.bind_buffer(buffer).unwrap();
    // Iterate over batches
    while let Some(batch) = cursor.fetch().unwrap() {
        // ... print values in batch ...
    }
}

pub fn fetch_with_truncation_check(
    &mut self,
    error_for_truncation: bool
) -> Result<Option<&B>, Error>

Fills the bound buffer with the next row set. Should error_for_truncation be trueand any diagnostic indicate truncation of a value an error is returned.

Return

None if the result set is empty and all row sets have been extracted. Some with a reference to the internal buffer otherwise.

Call this method to find out wether there are any truncated values in the batch, without inspecting all its rows and columns.

use odbc_api::{buffers::TextRowSet, Cursor};

fn print_all_values(mut cursor: impl Cursor) {
    let batch_size = 100;
    let max_string_len = 4000;
    let buffer = TextRowSet::for_cursor(batch_size, &mut cursor, Some(4000)).unwrap();
    let mut cursor = cursor.bind_buffer(buffer).unwrap();
    // Iterate over batches
    while let Some(batch) = cursor.fetch_with_truncation_check(true).unwrap() {
        // ... print values in batch ...
    }
}

Trait Implementations

impl<C, B> Drop for RowSetCursor<C, B>where
    C: AsStatementRef,

fn drop(&mut self)

Executes the destructor for this type.