[schema] fix unique together index handling We now provide a more compact indexname, using the schema constraint entity type and the position of the columns set in the entity type unique constraints list. This avoids a nasty name truncation issue. The UniqueTogetherError object is made smarter: it computes the rtypes, abstracting the underlying backend (pg/sqlserver vs sqlite). The `user friendly` adapter is much simplified since there is no longer any truncation issue. Uses a new logilab.database version (ticket #151507) and a new yams version (ticket #189299) Closes #2514939 [jcr: disable hooks when temporarily dropping CWUniqueTogetherConstraint entities]

/* -*- sql -*- 

   mysql specific registered procedures, 

*/

/* XXX limit_size version dealing with format as postgres version does.
   XXX mysql doesn't support overloading, each function should have a different name
       
   NOTE: fulltext renamed since it cause a mysql name conflict
 */

CREATE FUNCTION text_limit_size(vfulltext TEXT, maxsize INT)
RETURNS TEXT
NO SQL
BEGIN
    IF LENGTH(vfulltext) < maxsize THEN
       RETURN vfulltext;
    ELSE
       RETURN SUBSTRING(vfulltext from 1 for maxsize) || '...';
    END IF;
END ;;