Re: (ITS#3629) patch for problem with aggregated attributes in sql-back

[ando@sys-net.it]

kjellm@linpro.no wrote:

>Full_Name: Kjell-Magne Oierud
>Version: 2.2.24
>OS: linux
>URL: ftp://ftp.openldap.org/incoming/kjell-magne-oierud-050404.patch.1
>Submission from: (NULL) (80.232.36.140)
>
>
>Hi,
>
>I've upped a patchfile named kjell-magne-oierud-050404.patch.1 in
>ftp.openldap.org/incoming
>It's a patch against servers/slapd/back-sql/schema-map.c
>
>The problem:
>
>sql-back fails if you define some of an objectclass' attributes to be
>aggregates. More precisely, if you in ldap_attr_mapings define sel_expr to be
>anything like SUM(foo). sql-back will then try to exequte queries with invalid
>ORDER BY clauses: 
>  SELECT SUM(foo) AS bar ... ORDER BY SUM(foo)
>                                      ^^^^^^^^
>
>The solution:
>
>My patch fixes this by instead using the alias:
>  SELECT SUM(foo) AS bar ... ORDER BY bar
>  
>
The patch looks fine, although I'm not sure that ordering by the alias 
name will work on all RDBMSes; while (although not being a good enough 
reason) with PostgreSQL the order by clause works fine with both 
aggregate data and alias name.  Maybe we'd better provide an extra 
switch in ldap_attr_mappings to handle these cases.

p.


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