Struct udf::SqlArg

pub struct SqlArg<'a, S: UdfState> { /* private fields */ }

A single SQL argument, including its attributes

This struct contains the argument itself. It uses a typestate pattern (S) to have slightly different functionality when used during initialization and during processing.

Implementations

impl<'a, T: UdfState> SqlArg<'a, T>

pub fn value(&self) -> SqlResult<'a>

The actual argument type and value

pub fn attribute(&'a self) -> &'a str

A string representation of this argument’s identifier

impl<'a> SqlArg<'a, Init>

This includes functions that are only applicable during initialization

pub fn is_const(&self) -> bool

Determine whether an argument may be constant

During initialization, a value is const if it is not None. This provides a simple test to see if this is true.

There is no way to differentiate between “not const” and “const but NULL” when we are in the Process step.

pub fn maybe_null(&self) -> bool

Whether or not this argument may be NULL

pub fn set_type_coercion(&mut self, newtype: SqlType)

Instruct the SQL application to coerce the argument’s type. This does not change the underlying value visible in .value.

pub fn get_type_coercion(&self) -> SqlType

Retrieve the current type coercision

Trait Implementations

impl<'a, S: Debug + UdfState> Debug for SqlArg<'a, S>

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

Formats the value using the given formatter.