logilab-database #128160 Index identifier exceed max length for most backend [validation pending]

Identifier used for multi column index are very likely to exceed maximun
identifier lenght. Result vary from truncated name to crash.

Most database have a low limit:

* postgress have a 63 char limit.
http://www.postgresql.org/docs/current/interactive/sql-syntax-lexical.html#SQL-SYNTAX-IDENTIFIERS

* mysql have a 64 char limit
http://dev.mysql.com/doc/refman/5.0/en/identifiers.html

* SQL server 128 http://msdn.microsoft.com/en-us/library/ms143432.aspx

* sqlite have not limit

prioritynormal
typeenhancement
done in1.11.0
load1.000
load left0.000
closed by<not specified>