Today I see a PostgreSQL SQL book and find some interesting commands below. Is there any similar SQL commands under ADO?? 1. Meta-Command \d_\dt List All TAbles \dv List All View ...... List All Query (equal to View??) ...... List All Users 2. Frequency Statistic Select n_distinct, most_common_vals, most_common_freqs FROM ..... ==> these 3 terms are system terms. Result is showing N-th data/value occuring with top frequency in a table's field. Besides, please help: 3. There is a System table in MS Access "MsysObjects". I can open it in MS Access easily, without any password needed, but not in my application. How to solve it? 4. I have searched through Google with keywords SQL ADO or SQL "OLE DB", I feel very strange that there is only a few data for the former, and None for the latter. Even though their ultimate data engine may be ODBC or Jet, their SQL language in User-Level should be defined by themselves. (Otherwise, there will not be so many SQL language around MS applications :> ) Could you introduce me any tutorial and handbook web site for it??