Not responding to any particular comment, just the theme of this part of the thread:
Yes, design and implementation are two different things. Poor implementation can be done by anyone in any platform, so let's stick to platform capabilities. If you don't add RI to a relational DBMS then it's just as messed up as if you don't delete all MV detail item when you delete a related master item. There are two types of RI being discussed here: 1) In an MV item we can put data into a stream of attributes as well as multivalues and subvalues. The RDBMS requires relations where we use multivalued sets. The DBA defines relations in schema and the DBMS then maintains the integrity of the references (referential integrity). With proper RI in place, in the RDBMS you can't delete (for example) a customer record without deleting the related customer_phone records. In MV since this is all in the same record we don't have this exact problem - you can't say the MV platform does RI here, we're simply using a storage mechanism that makes RI unnecessary for this type of update. 2) MV maintains master/detail items in a manner similar to the RDBMS (with foreign keys, translates, etc). In this case relations in the RDBMS are still defined in the schema and the same rules as above apply. In MV, since we've ventured into multi-file/multi-item sets, it's not the job of the BASIC programmer to maintain the RI. RI in this regard is Not managed by the MV DBMS. Relational developers can choose to maintain such RI programmatically, but that's not even a thought in that world because fundamentally they rely on the DBMS to perform that function. The comments about the efficiencies of RI and whether or not MV does RI at all have all been made with regard to type#1 above. I'll maintain that the MV DBMS does not do RI in the type#2 case where RI actually has any meaning in this model. Tony Gravagno Nebula Research and Development TG@ remove.pleaseNebula-RnD.com Nebula R&D sells mv.NET and other Pick/MultiValue products worldwide, and provides related development services remove.pleaseNebula-RnD.com/blog Visit PickWiki.com! Contribute! _______________________________________________ U2-Users mailing list [email protected] http://listserver.u2ug.org/mailman/listinfo/u2-users
