Trait datafusion_sql::unparser::dialect::Dialect

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pub trait Dialect: Send + Sync {
    // Required method
    fn identifier_quote_style(&self, _identifier: &str) -> Option<char>;

    // Provided methods
    fn supports_nulls_first_in_sort(&self) -> bool { ... }
    fn use_timestamp_for_date64(&self) -> bool { ... }
    fn interval_style(&self) -> IntervalStyle { ... }
    fn float64_ast_dtype(&self) -> DataType { ... }
    fn utf8_cast_dtype(&self) -> DataType { ... }
    fn large_utf8_cast_dtype(&self) -> DataType { ... }
    fn date_field_extract_style(&self) -> DateFieldExtractStyle { ... }
    fn int64_cast_dtype(&self) -> DataType { ... }
    fn timestamp_cast_dtype(
        &self,
        _time_unit: &TimeUnit,
        tz: &Option<Arc<str>>,
    ) -> DataType { ... }
}
Expand description

Dialect to use for Unparsing

The default dialect tries to avoid quoting identifiers unless necessary (e.g. a instead of "a") but this behavior can be overridden as needed

Note: This trait will eventually be replaced by the Dialect in the SQLparser package

See https://github.com/sqlparser-rs/sqlparser-rs/pull/1170 See also the discussion in https://github.com/apache/datafusion/pull/10625

Required Methods§

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fn identifier_quote_style(&self, _identifier: &str) -> Option<char>

Return the character used to quote identifiers.

Provided Methods§

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fn supports_nulls_first_in_sort(&self) -> bool

Does the dialect support specifying NULLS FIRST/LAST in ORDER BY clauses?

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fn use_timestamp_for_date64(&self) -> bool

Does the dialect use TIMESTAMP to represent Date64 rather than DATETIME? E.g. Trino, Athena and Dremio does not have DATETIME data type

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fn interval_style(&self) -> IntervalStyle

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fn float64_ast_dtype(&self) -> DataType

Does the dialect use DOUBLE PRECISION to represent Float64 rather than DOUBLE? E.g. Postgres uses DOUBLE PRECISION instead of DOUBLE

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fn utf8_cast_dtype(&self) -> DataType

The SQL type to use for Arrow Utf8 unparsing Most dialects use VARCHAR, but some, like MySQL, require CHAR

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fn large_utf8_cast_dtype(&self) -> DataType

The SQL type to use for Arrow LargeUtf8 unparsing Most dialects use TEXT, but some, like MySQL, require CHAR

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fn date_field_extract_style(&self) -> DateFieldExtractStyle

The date field extract style to use: DateFieldExtractStyle

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fn int64_cast_dtype(&self) -> DataType

The SQL type to use for Arrow Int64 unparsing Most dialects use BigInt, but some, like MySQL, require SIGNED

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fn timestamp_cast_dtype( &self, _time_unit: &TimeUnit, tz: &Option<Arc<str>>, ) -> DataType

The SQL type to use for Timestamp unparsing Most dialects use Timestamp, but some, like MySQL, require Datetime Some dialects like Dremio does not support WithTimeZone and requires always Timestamp

Implementors§