Enum Modifier 

pub enum Modifier {
    Distinct,
    DistinctRow,
    LowPriority,
    HighPriority,
    Delayed,
    Quick,
    Ignore,
    StraightJoin,
    SmallResult,
    BigResult,
    BufferResult,
    NoCache,
    CalcFoundRows,
}

One of MySQL’s statement modifiers — the keywords between a statement’s first word and its real content.

MySQL spreads these across four productions:

SELECT [ALL | DISTINCT | DISTINCTROW] [HIGH_PRIORITY] [STRAIGHT_JOIN]
       [SQL_SMALL_RESULT] [SQL_BIG_RESULT] [SQL_BUFFER_RESULT]
       [SQL_NO_CACHE] [SQL_CALC_FOUND_ROWS] …
INSERT [LOW_PRIORITY | DELAYED | HIGH_PRIORITY] [IGNORE] …
UPDATE [LOW_PRIORITY] [IGNORE] …
DELETE [LOW_PRIORITY] [QUICK] [IGNORE] …

The order below is the grammar’s order, and Modifiers keeps its list sorted by it. That is the whole reason this is an enum rather than bob’s []string: bob appends the keywords in whatever order the mods were written, so im.Ignore(), im.HighPriority() produces INSERT IGNORE HIGH_PRIORITY, which MySQL rejects. Here mod order cannot affect the output.

Which modifiers a statement permits is decided by which of them its mod module re-exports, exactly as with the clause traits.

ALL is the default in SELECT and adds nothing, so it is not representable — the absence of Distinct is what it means.

Variants

Distinct

DISTINCT — drop duplicate result rows.

DistinctRow

DISTINCTROW, MySQL’s synonym for DISTINCT.

LowPriority

LOW_PRIORITY — wait for readers before writing.

HighPriority

HIGH_PRIORITY — jump the queue ahead of pending writes.

Delayed

DELAYED — accepted and deprecated; MySQL treats it as INSERT and warns.

Quick

QUICK — do not merge index leaves while deleting.

Ignore

IGNORE — turn errors that would abort the statement into warnings.

StraightJoin

STRAIGHT_JOIN — join tables in the order they are written.

SmallResult

SQL_SMALL_RESULT — the result set is small; use an in-memory temp table.

BigResult

SQL_BIG_RESULT — the result set is large; sort rather than use an index.

BufferResult

SQL_BUFFER_RESULT — force the result into a temporary table.

NoCache

SQL_NO_CACHE — do not read or write the query cache.

CalcFoundRows

SQL_CALC_FOUND_ROWS — count the rows a LIMIT discarded.

Implementations

impl Modifier

pub fn as_str(self) -> &'static str

The keyword, as written.

Trait Implementations

impl Clone for Modifier

fn clone(&self) -> Modifier

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Modifier

impl Debug for Modifier

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

Formats the value using the given formatter.

impl Eq for Modifier

impl Hash for Modifier

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for Modifier

fn cmp(&self, other: &Modifier) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for Modifier

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

Equality operator ==.

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

Inequality operator !=.

impl PartialOrd for Modifier

fn partial_cmp(&self, other: &Modifier) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StructuralPartialEq for Modifier