thanks Dingo. Marcin gave me help on this as well. He suggests to scan for "dead" symbols and then in the Symbol | Information window look for "Use local database" and then use "Yes". This way the data will not be overwritten and the data will stay with that symbol.
Marcin added to this: You can also use e.g. Tools -> Database Purify option to find non-traded symbols and add them to the watchlist. Additionally - if you want to change the properties on multiple tickers - then have a look at the following procedure: http://www.amibroker.com/kb/2006/09/01/how-to-change-property-for-multiple-symbols-at-once/ I will start scanning for "dead" symbols every day. Only the ones that are usefull for me, the highly liquid stocks and set them manually. regards, Ed ----- Original Message ----- From: dingo To: [email protected] Sent: Tuesday, May 29, 2007 5:03 PM Subject: RE: [amibroker] Are old symbols saved in local data base? With a "little" work you can do this yourself by writing a script that you run before you update from QP. The script would export all tickers in your current QP db to csv's and then it would import them into a separate stand alone db that you would use to test. A lot of work if you try to do it manually but if you write that scipt and make it a wrapper for the QP downloader then it would be "automatic". d ---------------------------------------------------------------------------- From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of Edward Pottasch Sent: Tuesday, May 29, 2007 2:43 AM To: [email protected] Subject: Re: [amibroker] Are old symbols saved in local data base? Gary from QP replied to my question and he says. "We don't keep dead symbols, they will be purged more frequently that in the past, as the dead symbols cause problems for others." I guess if QP does not keep dead symbols then automatically they are emptied out. In Amibroker the symbol is still there but there is no data. I don't think there is a setting in Amibroker that allows you to keep them in the data base. For portfolio backtesting this is a bad thing in my opinion. These dead symbols used to stay in the database for a long time which I liked since it gives a good idea how a portfolio type system would have performed in the past. Now you only see survivers and companies that have eaten up others. I remember that there is an EOD data service that keeps dead symbols in the database. Which one? Anyone know? rgds, Ed ----- Original Message ----- From: Edward Pottasch To: [email protected] Sent: Monday, May 28, 2007 9:39 AM Subject: Re: [amibroker] Are old symbols saved in local data base? hi, I am struggling with this myself. It seems that discontinued symbols are automatically emptied out. When I calculate my backtest for monday I get a diiferent result with respect to friday because a few symbols that were giving signals are removed (HCA, CMVT, maybe others, who knows ...). It would be nice if these symbols would remain in the database with the data still there. Now we are just left with an empty symbol. Not sure if this is due to QP or Amibroker, or if we can set something so they will remain in the database. rgds, Ed ----- Original Message ----- From: Keith McCombs To: [email protected] Sent: Sunday, May 27, 2007 10:02 PM Subject: [amibroker] Are old symbols saved in local data base? I'm using the QP database. If it is configured to use "Local data storage", are old symbols along with their Market, Group, etc. memberships saved in the local database after I do a Configure to add new symbols, or are discontinued symbols deleted from the local database?
