clickhouse.rs

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use crate::dialect::{Dialect, DialectFlags};

// A [`Dialect`] for [ClickHouse](https://clickhouse.com/).
#[derive(Debug)]
pub struct ClickHouseDialect(DialectFlags);

impl Default for ClickHouseDialect {
    fn default() -> Self {
        Self(DialectFlags {
            supports_string_literal_backslash_escape: true,
            supports_select_wildcard_except: true,
            describe_requires_table_keyword: true,
            require_interval_qualifier: true,
            ..Default::default()
        })
    }
}

impl Dialect for ClickHouseDialect {
    fn flags(&self) -> &DialectFlags {
        &self.0
    }

    fn is_identifier_start(&self, ch: char) -> bool {
        // See https://clickhouse.com/docs/en/sql-reference/syntax/#syntax-identifiers
        ch.is_ascii_lowercase() || ch.is_ascii_uppercase() || ch == '_'
    }

    fn is_identifier_part(&self, ch: char) -> bool {
        self.is_identifier_start(ch) || ch.is_ascii_digit()
    }
}