Join

When joining multiple tables, results are not automatically mapped to a single class. You must either:

1. Use a custom JoinedTable class (see Joined Tables), or
2. Return a Tuple of table types.

📝 Note: C# Tuple<T1,T2,...> supports up to 8 types. While ValueTuple allows more, support is not planned.

Using Joined Table Class

When defined properly, the following query will map the selected fields to the corresponding properties of the class.

// Select single row as joined type
JoinedTable row = dbConnector.QueryBuilder().Build(query => query
    .Select<ExampleTable>()
    .Select<ChildTable>()
    .From<ExampleTable>()
    .Join<ChildTable, ExampleTable>(
        child  => child.ParentId,
        parent => parent.Id
    )
    .OrderBy<ExampleTable>(
        row => row.Id,
        OrderDirection.DESC
    )
    .Limit(1)
    .Select()
).FirstOrDefault<JoinedTable>();

Using Tuple

When returning a Tuple<T1, T2,...T8> the QueryBuilder will try to determine to which class do belong the returned columns, and assign them properly.

// Select single row as a class tuple
Tuple<ExampleTable, ChildTable> joinedTypeRow = dbConnector.QueryBuilder().Build(query => query
    .Select<ExampleTable>()
    .Select<ChildTable>()
    .From<ExampleTable>()
    .Join<ChildTable, ExampleTable>(
        child  => child.ParentId,
        parent => parent.Id
    )
    .OrderBy<ExampleTable>(
        row => row.Id,
        OrderDirection.DESC
    )
    .Limit(1)
    .Select()
).FirstOrDefault<ExampleTable, ChildTable>();