Brian: Thanks for the detailed tips...good stuff.
You said: >>I meant to warn you that it is not good practise to append new data to an existing, AQ created, database for backtesting (susceptible to corruption).... it's OK for temporary working databases (scanning for current signals etc) ... for backtesting take a history and quarantine the database. This has me worried, as I am working myself not only towards backtesting on which to depend, but for an AQ maintained db to be my working db for O/H/L/C/V data. Can you expand on your comment and share alternatives or options to "maintain quality" with an AQ updated db. Ken -----Original Message----- From: amibroker@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of brian_z111 Sent: Friday, November 14, 2008 8:39 PM To: amibroker@yahoogroups.com Subject: [amibroker] Re: Another AQ Question a) For an existing database that includes symbosl with no data: - Tools >> Database Purify - Select reference >> All Symbols >> select All Symbols/N == 1, Report Missing Quotes - Deselect other report options - Default threshold is OK - Analyse - Click on column header to sort (separate Missing from No Quotes) - Shift/click first and last NoQuotes symbols - Right Click and send to watchlist Normal procedure to delete WL symbols from DB b) For a new EOD database: - create a new blank database - leave AB open - open AQ and import ticker list into AQ - uncheck AutoImport - set AQ dates to download one bar (quicker) - download and symbols will record errors - AQ >> Edit >> Toggle (switches checked symbols to non error symbol) - Check AutoImport - Set download dates to required history - Download (only symbols with data will be `pushed' to AB) I didn't have time to check method B completely... I am pretty certain it works ... if not tweaking it a little will get results (save filtered list and restart database). AFAIK you can't sort the AQ columns or delete all error symbols from the AQ list. I couldn't find the toggle to turn on the 'hidden' AB help manual either. I meant to warn you that it is not good practise to append new data to an existing, AQ created, database for backtesting (susceptible to corruption).... it's OK for temporary working databases (scanning for current signals etc) ... for backtesting take a history and quarantine the database. There are some tricks to using AQ ... a few are documented at the UKB although the DBM section is incomplete and becoming dated now :-( brian_z --- In amibroker@yahoogroups.com, "Ken Close" <[EMAIL PROTECTED]> wrote: > > As I load symbols into AQ and fetch data, a bunch of symbols are reported as > errors, obviously symbols which have changed names or are no longer listed. > > My question is whether there is a convenient way to purge the database of > the out of date symbols, by somehow reading the window of results for those > having errors, and then turning that into some mass deletion list. > > Does such a method exist? > > Thanks. > Ken > ------------------------------------ **** IMPORTANT **** This group is for the discussion between users only. This is *NOT* technical support channel. ********************* TO GET TECHNICAL SUPPORT from AmiBroker please send an e-mail directly to SUPPORT {at} amibroker.com ********************* For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG: http://www.amibroker.com/devlog/ For other support material please check also: http://www.amibroker.com/support.html ********************************* Yahoo! Groups Links