Struct CLob

pub struct CLob(/* private fields */);

LOB implementation for unicode Strings (deprecated).

CLob is used within HdbValue::CLOB (deprecated) instances received from the database.

Bigger LOBs are not transferred completely in the first roundtrip, instead more data is fetched in subsequent roundtrips when needed.

CLob respects the Connection’s lob read length (see Connection::set_lob_read_length).

Implementations

impl CLob

pub async fn into_string(self) -> Result<String, HdbError>

Converts the CLob into the contained String.

All outstanding data (data that were not yet fetched from the server) are fetched into this CLob object, before the complete data, as far as they were not yet read from this CLob object, are returned.

Example

 let mut result_set = connection.query(query)?;
 let mut clob = result_set.into_single_row().await?.into_single_value()?.try_into_clob()?;
 let s = clob.into_string(); // String, can be huge

Alternative

For larger objects, a streaming approach using CLob::write_into might by more appropriate, to avoid total allocation of the large object.

Errors

Several variants of HdbError can occur.

pub async fn write_into<W>(self, writer: &mut W) -> Result<(), HdbError>

where W: Unpin + AsyncWriteExt,

Writes the content into the given writer.

Reads outstanding data in chunks of size Connection::lob_read_length from the database and writes them immediately into the writer, thus avoiding that all data are materialized within this CLob.

Errors

Various errors can occur.

pub async fn read_slice( &mut self, offset: u64, length: u32, ) -> Result<CharLobSlice, HdbError>

Reads from given offset and the given length, in bytes.

Errors

Several variants of HdbError can occur.

pub fn total_byte_length(&self) -> u64

Total length of data, in bytes.

pub fn is_empty(&self) -> bool

Returns true if the CLob does not contain data.

pub fn cur_buf_len(&self) -> usize

Current size of the internal buffer, in bytes.

pub fn server_usage(&self) -> ServerUsage

Provides information about the the server-side resource consumption that is related to this CBLob object.

Trait Implementations

impl Clone for CLob

fn clone(&self) -> CLob

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for CLob

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

Formats the value using the given formatter.