X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=t%2Fprefetch%2Fmultiple_hasmany.t;h=cee298ad5fd5f03aa5a02088a0dab25a38eb541e;hb=4cf8bfe6f4ccae8e0c26081f1f8f2ebd88e7ec99;hp=6ef7a5337b515822168c694278515c139956d7a4;hpb=e9bd1473080b4aaf94e2be97329d74703d41a353;p=dbsrgits%2FDBIx-Class-Historic.git

diff --git a/t/prefetch/multiple_hasmany.t b/t/prefetch/multiple_hasmany.t
index 6ef7a53..cee298a 100644
--- a/t/prefetch/multiple_hasmany.t
+++ b/t/prefetch/multiple_hasmany.t
@@ -128,3 +128,45 @@ my $w;
             "warning on ->$_ attempt prefetching several same level has_manys (M -> 1 -> M + M)");
     }
 }
+
+__END__
+The solution is to rewrite ResultSet->_collapse_result() and
+ResultSource->resolve_prefetch() to focus on the final results from the collapse
+of the data. Right now, the code doesn't treat the columns from the various
+tables as grouped entities. While there is a concept of hierarchy (so that
+prefetching down relationships does work as expected), there is no idea of what
+the final product should look like and how the various columns in the row would
+play together. So, the actual prefetch datastructure from the search would be
+very useful in working through this problem. We already have access to the PKs
+and sundry for those. So, when collapsing the search result, we know we are
+looking for 1 cd object. We also know we're looking for tracks and tags records
+-independently- of each other. So, we can grab the data for tracks and data for
+tags separately, uniqueing on the PK as appropriate. Then, when we're done with
+the given cd object's datastream, we know we're good. This should work for all
+the various scenarios.
+
+My reccommendation is the row's data is preprocessed first, breaking it up into
+the data for each of the component tables. (This could be done in the single
+table case, too, but probably isn't necessary.) So, starting with something
+like:
+  my $row = {
+    t1.col1 => 1,
+    t1.col2 => 2,
+    t2.col1 => 3,
+    t2.col2 => 4,
+    t3.col1 => 5,
+    t3.col2 => 6,
+  };
+it is massaged to look something like:
+  my $row_massaged = {
+    t1 => { col1 => 1, col2 => 2 },
+    t2 => { col1 => 3, col2 => 4 },
+    t3 => { col1 => 5, col2 => 6 },
+  };
+At this point, find the stuff that's different is easy enough to do and slotting
+things into the right spot is, likewise, pretty straightforward. Instead of
+storing things in a AoH, store them in a HoH keyed on the PKs of the the table,
+then convert to an AoH after all collapsing is done.
+
+This implies that the collapse attribute can probably disappear or, at the
+least, be turned into a boolean (which is how it's used in every other place).