Hi Mr.Ramani

Thanks for your response, Can you help me?

I want to add some functions into PostgreSQL codes for this purpose :

    - For first step, I want to add a column automatically, that means when a user use CREATE TABLE code for creating tables, without his/her know about added column,  a column add in the created table and calculate hash that row ...

            I want to add a column without knowing user that used it, automatically ...

    - for second step, I want to know that columns that the unauthorized user changed it. In fact, i want to recognize changed rows that unauthorized users modified them, without the user know about existence of added columns that calculate hash of every rows ...

Can you help me about this work? Can you tell me what should i do for this work and where should i change PostgreSQL Codes for this purpose? Which Class or every things ???