src/dialect/mssql.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;

/// A [`Dialect`] for [Microsoft SQL Server](https://www.microsoft.com/en-us/sql-server/)
#[derive(Debug)]
pub struct MsSqlDialect {}

impl Dialect for MsSqlDialect {
    fn is_delimited_identifier_start(&self, ch: char) -> bool {
        ch == '"' || ch == '['
    }

    fn is_identifier_start(&self, ch: char) -> bool {
        // See https://docs.microsoft.com/en-us/sql/relational-databases/databases/database-identifiers?view=sql-server-2017#rules-for-regular-identifiers
        ch.is_alphabetic() || ch == '_' || ch == '#' || ch == '@'
    }

    fn is_identifier_part(&self, ch: char) -> bool {
        ch.is_alphabetic()
            || ch.is_ascii_digit()
            || ch == '@'
            || ch == '$'
            || ch == '#'
            || ch == '_'
    }

    /// SQL Server has `CONVERT(type, value)` instead of `CONVERT(value, type)`
    /// <https://learn.microsoft.com/en-us/sql/t-sql/functions/cast-and-convert-transact-sql?view=sql-server-ver16>
    fn convert_type_before_value(&self) -> bool {
        true
    }

    fn supports_connect_by(&self) -> bool {
        true
    }
}