[GENERAL] Set valued attributes ?
Does anyone know how to make an attribute a collection of OIDs? I haven't found any reference of this object-oriented feature in Postgres online manuals. Please, let me know any hints/links or anything that could help me doing the following: === Assume that each row of tables is identified by OID. I want to define an attribute, say (t1.c2), as a collection of OIDs linking to rows of table t2. At the same time the attribute (t1.c3) contains a collection of OIDs linking to rows of table t3. === How do I do to make the postgres "navigate through OID links", to prevent expensive access methods (joins, sequential or indexed) ?
[GENERAL] ORDBMS vs OODBMS
Hello folks I'm an engineering student and I would be very interested to learn the pros and cons between these two DataBases: - Versant : commercial OODBMS (Object-Oriented) - PostgreSQL : open source ORDBMS (Object-Relational) (Other DB like Oracle are ERDBMS and not ORDBMS if I guess right) It seems to me the main disadvantage of ORDBMS is the still presence of Impendance Mismatch, which is completely absent in OODBMS. Well, I would like to focus the meaning of the "Object" point of view of PostgreSQL: does it offer just the arbitrariness of data structure? What else? Can a row be assimilated to an object ? Please let me know any experiences which can show interesting aspects of PostreSQL vs Versant (and/or other OODBMS in general) ? The good thing in Versant is that it's 100% Object-Oriented and works well with Java (through JVI interface). The sad thing is that it's closed-source and it's very commercial. The good thing in PostgreSQL is that it's open-source and is available everywhere. I hope to find a lot of more good points related to PostgreSQL. Regards Nico
