pub struct Sequence { /* private fields */ }
Expand description

A sequence is a generator of ordered integer values.

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impl Sequence

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pub fn find(name: &str) -> Result<Option<Self>, Error>

Find sequence by name.

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pub fn next(&mut self) -> Result<i64, Error>

Generate the next value and return it.

The generation algorithm is simple:

  • If this is the first time, then return the start value.
  • If the previous value plus the increment value is less than the minimum value or greater than the maximum value, that is “overflow”, so either raise an error (if cycle = false) or return the maximum value (if cycle = true and step < 0) or return the minimum value (if cycle = true and step > 0).

If there was no error, then save the returned result, it is now the “previous value”.

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pub fn set(&mut self, new_value: i64) -> Result<(), Error>

Set the “previous value” to new_value.

This function requires a “write” privilege on the sequence.

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pub fn reset(&mut self) -> Result<(), Error>

Set the sequence back to its original state.

The effect is that a subsequent next will return the start value. This function requires a “write” privilege on the sequence.

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> Same for T

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type Output = T

Should always be Self
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impl<T, U> TryFrom<U> for T
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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.