From 1d32d12e1f2d7d5f6565bbcddfb9edb9218ec1fe Mon Sep 17 00:00:00 2001 From: Boris Kolpackov Date: Wed, 21 Jan 2015 11:50:32 +0200 Subject: Add feature: duplicate/expression columns --- feature/list | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/feature/list b/feature/list index dff0004..f2043e0 100644 --- a/feature/list +++ b/feature/list @@ -23,3 +23,22 @@ Got two questions on the mailing list about that in one week. Maybe always diagnose lack of public ctor? Maybe with a warning if no relationship? The no_ctor pragma like no_id? + +? Duplicate columns + + It can sometimes be useful to map multiple data members to the same + column. For example, to map a shared_ptr to another object via id. + Or to update object id. + + To implement this, we will have to be able to ignore duplicates in + the INSERT statement and in generated schema. So there will have to + be quite a bit of work throughout (bind, init, column counts, etc). + + Also not clear if it is a good idea to always ignore duplicates + (could actually be a mistake) or only if the column name is + specified explicitly (still can be a mistake). Or mark it as a + duplicate with a special pragma. + + Is this a special case of something like "expression columns"? It + seems the only place where such a duplicate column will actually + be mentioned is the SELECT statement. -- cgit v1.1