Method lock_table_shared

src/sql-server-util/src/lib.rs:425–443

Lock the provided table to prevent writes but allow reads, uses `(TABLOCK, HOLDLOCK)`. This will set the transaction isolation level to `READ COMMITTED` and then obtain the lock using a `SELECT` statement that will not read any data from the table. The lock is released after transaction commit or rollback.

(
        &mut self,
        schema: &str,
        table: &str,
    )

    /// lock using a `SELECT` statement that will not read any data from the table.
    /// The lock is released after transaction commit or rollback.
    pub async fn lock_table_shared(
        &mut self,
        schema: &str,
        table: &str,
    ) -> Result<(), SqlServerError> {
        // Locks in MS SQL server do not behave the same way under all isolation levels. In testing,
        // it has been observed that if the isolation level is SNAPSHOT, these locks are ineffective.
        static SET_READ_COMMITTED: &str = "SET TRANSACTION ISOLATION LEVEL READ COMMITTED;";
        // This query probably seems odd, but there is no LOCK command in MS SQL. Locks are specified
        // in SELECT using the WITH keyword.  This query does not need to return any rows to lock the table,
        // hence the 1=0, which is something short that always evaluates to false in this universe.
        let query = format!(
            "{SET_READ_COMMITTED}\nSELECT * FROM {schema}.{table} WITH (TABLOCK, HOLDLOCK) WHERE 1=0;",
            schema = quote_identifier(schema),
            table = quote_identifier(table)
        );
        let _result = self.client.simple_query(query).await?;
        Ok(())
    }

    /// See [`Client::execute`].
    pub async fn execute<'q>(