Struct Nclob

pub struct Nclob { /* private fields */ }

A reference to Oracle data type NCLOB

This struct implements Read and Write to read and write characters. Read::read fails when buf is too small to store one character. Write::write fails when buf contains invalid UTF-8 byte sequence.

This also implements SeekInChars to seek to a position in characters. Note that there is no way to seek in bytes.

Notes

The size of LOBs returned by Lob::size and positions in SeekInChars are inaccurate if a character in the LOB requires more than one UCS-2 codepoint. That’s becuase Oracle stores CLOBs and NCLOBs using the UTF-16 encoding and the number of characters is defined by the number of UCS-2 codepoints.

Implementations

impl Nclob

pub fn new(conn: &Connection) -> Result<Nclob>

Returns a reference to a new temporary NCLOB which may subsequently be written and bound to a statement.

pub fn close(&mut self) -> Result<()>

Closes the LOB.

Trait Implementations

impl Clone for Nclob

fn clone(&self) -> Nclob

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Nclob

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

Formats the value using the given formatter.

impl FromSql for Nclob

fn from_sql(val: &SqlValue<'_>) -> Result<Self>

impl Lob for Nclob

fn size(&self) -> Result<u64>

Returns the size of the data stored in the LOB.

fn truncate(&mut self, new_size: u64) -> Result<()>

Shortens the data in the LOB so that it only contains the specified amount of data.

fn chunk_size(&self) -> Result<usize>

Returns the chunk size, in bytes, of the internal LOB. Reading and writing to the LOB in multiples of this size will improve performance.

fn open_resource(&mut self) -> Result<()>

Opens the LOB resource for writing. This will improve performance when writing to the LOB in chunks and there are functional or extensible indexes associated with the LOB. If this function is not called, the LOB resource will be opened and closed for each write that is performed. A call to the close_resource should be done before performing a call to the function Connection.commit.

fn close_resource(&mut self) -> Result<()>

Closes the LOB resource. This should be done when a batch of writes has been completed so that the indexes associated with the LOB can be updated. It should only be performed if a call to function open_resource has been performed.

fn is_resource_open(&self) -> Result<bool>

Returns a boolean value indicating if the LOB resource has been opened by making a call to the function open_resource.

impl Read for Nclob

fn read(&mut self, buf: &mut [u8]) -> Result<usize>

Pull some bytes from this source into the specified buffer, returning how many bytes were read.

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize>

Reads all bytes until EOF in this source, placing them into buf.

fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize, Error>

Like read, except that it reads into a slice of buffers.

fn is_read_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Reader has an efficient read_vectored implementation.

fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>

Reads all bytes until EOF in this source, appending them to buf.

fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>

Reads the exact number of bytes required to fill buf.

fn read_buf(&mut self, buf: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Pull some bytes from this source into the specified buffer.

fn read_buf_exact(&mut self, cursor: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Reads the exact number of bytes required to fill cursor.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adaptor for this instance of Read.

fn bytes(self) -> Bytes<Self>

where Self: Sized,

Transforms this Read instance to an Iterator over its bytes.

fn chain<R>(self, next: R) -> Chain<Self, R>

where R: Read, Self: Sized,

Creates an adapter which will chain this stream with another.

fn take(self, limit: u64) -> Take<Self>

where Self: Sized,

Creates an adapter which will read at most limit bytes from it.

impl SeekInChars for Nclob

fn seek_in_chars(&mut self, pos: SeekFrom) -> Result<u64>

Seek to an offset, in characters, in a stream.

fn stream_position_in_chars(&mut self) -> Result<u64>

Returns the current seek position from the start of the stream.

impl ToSql for Nclob

fn oratype(&self, _conn: &Connection) -> Result<OracleType>

fn to_sql(&self, val: &mut SqlValue<'_>) -> Result<()>

impl ToSqlNull for Nclob

fn oratype_for_null(_conn: &Connection) -> Result<OracleType>

impl Write for Nclob

fn write(&mut self, buf: &[u8]) -> Result<usize>

Writes a buffer into this writer, returning how many bytes were written.

fn flush(&mut self) -> Result<()>

Flushes this output stream, ensuring that all intermediately buffered contents reach their destination.

fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize, Error>

Like write, except that it writes from a slice of buffers.

fn is_write_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Writer has an efficient write_vectored implementation.

fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>

Attempts to write an entire buffer into this writer.

fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

🔬This is a nightly-only experimental API. (write_all_vectored)

Attempts to write multiple buffers into this writer.

fn write_fmt(&mut self, args: Arguments<'_>) -> Result<(), Error>

Writes a formatted string into this writer, returning any error encountered.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adapter for this instance of Write.