DapperLib / DapperLib/Dapper

Using Multi-Mapping type[] parameter with QueryUnbufferedAsync

Open
#1,978 6 comments 2 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

Dominant language
C#
Stars
18.4k
Forks
3.7k
Avg merge
5h 8m
Merged PRs (30d)
1

Description

Does an overload exist to use the type[] parameter for the QueryUnbufferedAsync overload? My goal is to have QueryUnbufferedAsync work similarly to QueryAsync when specifying a collection of types. Something like this:

var query = "SELECT * FROM Customers C JOIN Addresses A ON C.ID = A.CustomerID";
using var connection = connectionFactory.GetConnection();

//Currently possible
var customers = await connection.QueryAsync<Customer>(query, new Type[] { typeof(Customer), typeof(Address) }, (row) =>
{
    var customer = (Customer)row[0];
    customer.Address = (Address)row[1];
    return customer;
});
return customers;

//Would like to do this:
await foreach(var customer in connection.QueryUnbufferedAsync<Customer>(query, new Type[] { typeof(Customer), typeof(Address) }, (row) =>
{
    var customer = (Customer)row[0];
    customer.Address = (Address)row[1];
    return customer;
}))
{
    yield return customer;
}

Contributor guide

No contributing guide indexed for this repository

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

The relevant entry points are QueryUnbufferedAsync and QueryAsync; compare their overloads and multi-mapping signatures first. Done means QueryUnbufferedAsync accepts the type[] and mapping callback shown and supports the requested async iteration pattern, with coverage for that usage.

Written by the indexing model from the issue text.

Assessment

Tech stack
csharp, sql
Domain
backend-api-design, databases
Issue type
Feature
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
45/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.