Struct Nullable

pub struct Nullable<T> { /* private fields */ }

Wraps a type T together with an additional indicator. This way the type gains a Null representation, those memory layout is compatible with ODBC.

Implementations

impl<T> Nullable<T>

pub fn new(value: T) -> Self

pub fn null() -> Self

where T: Default,

pub fn as_opt(&self) -> Option<&T>

pub fn into_opt(self) -> Option<T>

Trait Implementations

impl<T> CData for Nullable<T>

where T: Pod,

fn cdata_type(&self) -> CDataType

The identifier of the C data type of the value buffer. When it is retrieving data from the data source with fetch, the driver converts the data to this type. When it sends data to the source, the driver converts the data from this type.

fn indicator_ptr(&self) -> *const isize

Indicates the length of variable sized types. May be zero for fixed sized types. Used to determine the size or existence of input parameters.

fn value_ptr(&self) -> *const c_void

Pointer to a value corresponding to the one described by cdata_type.

fn buffer_length(&self) -> isize

Maximum length of the type in bytes (not characters). It is required to index values in bound buffers, if more than one parameter is bound. Can be set to zero for types not bound as parameter arrays, i.e. CStr.

impl<T> CDataMut for Nullable<T>

where T: Pod,

fn mut_indicator_ptr(&mut self) -> *mut isize

Indicates the length of variable sized types. May be zero for fixed sized types.

fn mut_value_ptr(&mut self) -> *mut c_void

Pointer to a value corresponding to the one described by cdata_type.

impl<T> CElement for Nullable<T>

where T: Pod,

fn assert_completness(&self)

Does nothing. T is fixed size and therfore always complete.

impl<T: Clone> Clone for Nullable<T>

fn clone(&self) -> Nullable<T>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T> Default for Nullable<T>

where T: Default,

fn default() -> Self

Returns the “default value” for a type.

impl<T> FetchRowMember for Nullable<T>

where T: Pod,

fn indicator(&self) -> Option<Indicator>

Indicator for variable sized or nullable types, None for fixed sized types.

fn find_truncation(&self, buffer_index: usize) -> Option<TruncationInfo>

Some if the indicator indicates truncation. Always None for fixed sized types.

unsafe fn bind_to_col( &mut self, col_index: u16, cursor: &mut StatementRef<'_>, ) -> Result<(), Error>

Bind row element to column. Only called for the first row in a row wise buffer.

impl<T> HasDataType for Nullable<T>

where T: Pod + HasDataType,

fn data_type(&self) -> DataType

The SQL data as which the parameter is bound to ODBC.

impl<T: Copy> Copy for Nullable<T>

impl<T> OutputParameter for Nullable<T>

where T: Pod + HasDataType,