ic_dbms_api/dbms/
foreign_fetcher.rs

1use crate::dbms::table::TableColumns;
2use crate::dbms::value::Value;
3use crate::prelude::{Database, IcDbmsResult};
4
5/// This trait defines the behavior of a foreign fetcher, which is responsible for
6/// fetching data from foreign sources or databases.
7///
8/// It takes a table name and returns the values associated with that table.
9pub trait ForeignFetcher: Default {
10    /// Fetches the data for the specified table and primary key values.
11    ///
12    /// # Arguments
13    ///
14    /// * `database` - The database from which to fetch the data.
15    /// * `table` - The name of the table to fetch data from.
16    /// * `pk_values` - The primary key to look for.
17    ///
18    /// # Returns
19    ///
20    /// A result containing the fetched table columns or an error.
21    fn fetch(
22        &self,
23        database: &impl Database,
24        table: &'static str,
25        local_column: &'static str,
26        pk_value: Value,
27    ) -> IcDbmsResult<TableColumns>;
28}
29
30/// A no-op foreign fetcher that does not perform any fetching.
31#[derive(Default)]
32pub struct NoForeignFetcher;
33
34impl ForeignFetcher for NoForeignFetcher {
35    fn fetch(
36        &self,
37        _database: &impl Database,
38        _table: &'static str,
39        _local_column: &'static str,
40        _pk_value: Value,
41    ) -> IcDbmsResult<TableColumns> {
42        unimplemented!("NoForeignFetcher should have a table without foreign keys");
43    }
44}
ic_dbms_api/dbms/foreign_fetcher.rs

ic_dbms_api/dbms/
foreign_fetcher.rs
