Hi, I'm starting to develop a zope products and I'm still confused on how to use ZODB. My current application development is using RDBMS concept such as following samples: employee table: Row First Name Last Name Age === ========== ========= === 1 Bob McBob 42 2 John Johnson 24 3 Steve Smith 38 - I can easily perform SQL statement to lookup for some information such as, total employee, who are above 30 years old, and who has the Lastname of 'Smith'. - I can easily retrieve information from multiple tables and combine it as data objects. But how can I do this in ZODB? I was looking at http://www.zope.org/Documentation/Books/ZDG/current/index_html but it just tell me briefly how to store objects and simple retrieval. I need to do complex queries or perform some transaction. Can anyone help me the way to query data in ZODB? thanks, Heri