Question

On a small pre-registration database, I’m using the following SQL to generate a VIEW whenever a specific user name is given. I’m using this mainly to get a snapshot whenever a sysadmin suspects duplicate names are registering. This will be done rarely (atmost once per hour), so the database schema shouldn’t be getting excessively big.

CREATE OR REPLACE TRIGGER upd_on_su_entry
    AFTER UPDATE OR INSERT
    ON PRE_REG_MEMBER
    FOR EACH ROW
BEGIN
    IF :new.MEMBER_NAME  = 'SysAdmin Dup Tester' THEN
        EXECUTE IMMEDIATE 'CREATE OR REPLACE VIEW mem_n AS SELECT :old.MEMBER_NAME, COUNT(:old.MEMBER_NAME) FROM MEMBER GROUP BY MEMBER_NAME';
    END IF;
END;

However, this appears to be a bloated, inefficient and erroneous way of working (according to my admin). Is there a fundamental error here ? Can I take an equivalent snapshot some other way?

I’m very new to SQL, so please bear with me.

Also, I want to be using the view as :

public void dups()throws Exception
{
    Calendar cal = Calendar.getInstance();
    jt.setText("Duplicate List at : "+ cal.getTime());
    try{
        rs=stat.executeQuery("select * from upd_on_su_entry");
        while(rs.next())
        {
            jt.append(rs.getString("MEMBER_NAME")+"\t");
            jt.append(rs.getString(2)+"\t");
        }
    }
    catch(Exception e){System.out.print("\n"+e);}
}

Answer 1

There seem to be some misunderstandings here.

1.) views are basically stored sql statements, not stored sql results, so your view will always display the data as it is at the point of querying the view.

2.) Never ever use DDL (create statements) and similar during normal processing of an application. Its just not the way databases are intended to work.

If you want a snapshot at a point in time, create a secondary table which contains all the columns of the original table plus a snapshot time stamp.

When ever you want to make a snapshot copy all the data you want from the original table into the snapshot table while adding the current time stamp.