Struct TextLimits 

#[non_exhaustive]
pub struct TextLimits {
    pub longest_varchar: Option<u32>,
    pub counted_in: VarcharUnit,
    pub source: LimitSource,
    pub text_is_not: Option<&'static str>,
}

What one engine holds in a text column: the longest varchar(n) it takes, how that length is counted, where the number came from, and what an unbounded text column cannot be there.

Answered by DialectCapabilities::text_limits. A length past the longest is refused by name before anything is rendered, as a decimal wider than the engine holds is.

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

longest_varchar: Option<u32>

The longest varchar(n) a column takes, where the engine has one.

counted_in: VarcharUnit

How Self::longest_varchar is counted.

source: LimitSource

Where the number came from.

text_is_not: Option<&'static str>

What the engine refuses an unbounded text column as, where it refuses it as a key — a key or UNIQUE, a primary key.

Implementations

impl TextLimits

pub const fn new( longest_varchar: u32, counted_in: VarcharUnit, source: LimitSource, ) -> Self

A longest varchar, counted in counted_in, from source.

pub const fn and_text_is_not(self, what: &'static str) -> Self

The same limits, for an engine that refuses an unbounded text as what — a key or UNIQUE.

pub fn misfit(&self, length: u32) -> Option<String>

Why varchar(length) does not fit, in a few plain words, or None when it does.

Trait Implementations

impl Clone for TextLimits

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for TextLimits

impl Debug for TextLimits

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

Formats the value using the given formatter.

impl Eq for TextLimits

impl PartialEq for TextLimits

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for TextLimits