Hello I create Enterprise Resource Planning apllication for construction branch. I need easy to lern, rebuild, flexible and with good performance O/R mapper. There is many option: - nHibernate, - SubSonic, - XPO, - Castle ActiveRecord, - Lightspeed, - CodeSmith, - Fluent nHibernate, - Visual Paradigm ORM. Probably for begining every orm is good for me but in future when me application grows, not exactly. Please, share with me yours experiance and let us choose the best solution. Best regards Lukas

Ok, thx for your advice. I'll try to learn LINQ to SQL.

Thx for you answer. Because I have 2 modules finshed from 4, I'll change the way of work with database during creation 2 new modules. In time I'll try to change everything, without simple dictionaries like for example types of invoices or types of education level. What you suggesting as an alternative ?? I thought about : - strong typed DataSet's, - LINQ to SQL (but I read that is more slow then classic ADO.NET), - Entity Framework, - ADO.NET (mode non-connection), - or something else ?? I'd like to just keep communicating with the database using stored procedures. Overall, I am not afraid of new challenges and if I need I'll learn new technologies. Thank you once again

Thank you for your answere. Unfortunetlly I have this mechanism in my application and I'm done 2 modules. It is hard to change everythig in this moment. But... is there a big problem if in my whole application with all modules I will be have maximum 100 000 rows in my whole tables in Data Base ? I don't know that 100 000 records whether much, and how much it affects the load on the system ? Because I want to sell this application with computer (notebook), my minimum requiments is: - Core 2 Duo 2GHz, - minimum 2GB RAM.

Hello, I write apllication(.NET 3.5 C#, SQL Server 2k8) (type ERP) with modules like: HRM, SCM, FRM, MRP. It is multi user application. I decide store all important data from DB in Dictionaries or List ex. for INVOICE i create Dictionary<int,> etc. To reduce connection with data base I have mechanism base on events to update specific data in my Dictionaries. I chose this solution because I don't want once again fill my GridView from DataBase when one record has been changed by another user. To synchronize my Dictionaries I want to use Query Notification and tracking changes mechanism (SQL Server 2008). And all work fine but .... Hypothetical situation. I have for example 20 Dictionaries and any of this Dictionary have 2000-5000 elements.I fill it when the user logs on to an application. How does it affect the weight of memory? Is that way - casched Dictionaries - is a better solution then load all data (ex.Invoices) from data base when i need use it ? Sorry for my English. It is not perfect.