If I could jump in here, too.....Many years ago when I first started using Amibroker, I wrestled with this very same issue (I was using QP). Tomasz showed me how to get the quotes from the external database to the local database, basically using the example from the thread. There is one other thing that may not be obvious though. Once you move your data to the local data base, any updates or maintenance the external database vendor does to the external database, will not be carried over to the local data base. I believe the suggestion was made to periodically refresh the local database by deleting it and recreating it from the external database, to incorporate the updates. Just for the record, "Maintenance" would be updating existing quotes/symbols when errors are found, not adding new data at the end of day.
It may also be beneficial to add that piece of info to the help file. I think that documenting that fact that after switching to a Local Database, data must be copied to it, and that the Local Database is "immune" to updates in the External Data Base after it is copied, would give a good perspective on how Local Databases work to users who are new at working with External/Local Databases. I hope this helps. Allan Wade _____ From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of Ken Close Sent: Tuesday, July 08, 2008 7:23 AM To: [email protected] Subject: Broker.master glitch perhaps Was: RE: [amibroker] More on Database Structure and Local Storage Thank you. >From the page: You may also choose to store the quotes retrieved from the external source to AmiBroker's own database for faster retrieval in subsequent accesses. If you want to do this, you should switch the 'Local data storage' setting to 'Enabled'. In spite of great proofreading by Yuki (I miss her posts), I still missed seeing any mention of needing to do a scan of the database source in order to transfer or write the data into the local database. A suggestion for the future would be to add your statement number 2 below should at some time be added to the html guide page (although I know it is not a very high priority issue). Would you have a suggestion on how I could preserve previously calculated values of an ordinal ranking indicator, right now thought to be saved in the OI field, and still have a method of updating both the daily price data and only the newly calculated ordinal ranking information based on the new price data? Maybe I need to turn away from this approach (OI field saving) and look to do an automatic import of an external file where I save the ordinal ranking data. What do you think? Thanks. I will give this a rest for awhile and continue programming. Ken _____ From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of Tomasz Janeczko Sent: Tuesday, July 08, 2008 9:46 AM To: [email protected] Subject: Re: [amibroker] More on Database Structure and Local Storage Hello, I belive that the document in the help file is pretty complete. Actually it was proof read by Yuki :-) (thanks!) As I wrote you can not WRITE to FastTrack database. You can however switch back and forth from local <-> FT. I won't go into repeating what is in the guide, instead will give you just the procedure you may use: 1. Start of the day 2. Set "Data source" to "FastTrack". Run ANY AA scan (can be one liner: buy=0;) on all symbols (that will copy files to AB local db) 3. Switch "Data source" to "(local database)". Now you have write access, you can write your data to OI field. 4. End of the day - turn back to "FastTrack" (your changes to OpenInterest will be lost at that moment). Best regards, Tomasz Janeczko amibroker.com ----- Original Message ----- From: Ken Close <mailto:[EMAIL PROTECTED]> To: [email protected] Sent: Tuesday, July 08, 2008 3:28 PM Subject: RE: [amibroker] More on Database Structure and Local Storage Hello Tomasz: Of course you are right, again, but the page in help/guide is still incomplete in order to impart a good understanding of how this all works. How does one use local database (say with FastTrack data) and still get nightly updates installed so everything works right? What does local database really mean as everyone has to get their data from some external source? I clicked on the DATA SOURCE (vs my previously just checking the Enable local storage button), and everything seemed the same. I could go between symbols in the tree, and things seemed to plot the same. There was no long disk activity suggesting that AB was writing data from the FT data files to the local AB data files. So how does that work? My critical question: Am I able to use FastTrack data, locally, and write custom values to OI that will be saved, AND STILL, somehow, update nightly FastTrack data? Can you say it is possible, and if so how are nightly updates accomplished? This is all critical to a custom application (as we have been discussing in other messages). Thanks for continuing to provide support on this issue. Ken _____ From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of Tomasz Janeczko Sent: Tuesday, July 08, 2008 8:12 AM To: [email protected] Subject: Re: [amibroker] More on Database Structure and Local Storage Hello, To switch to LOCAL database, you just go to File->Database Settings and change "Data SOURCE" to "(local database)". But that means that you are NOT using FastTrack as data source. You can *not* have both, i.e. using FastTrack as a data source and having database WRITE ability, because access to FastTrack database is READ ONLY. The only exceptions are COMPOSITES (and any symbol marked as "use local database only" in the Information window) - they are NOT present in external database and are always saved locally. It was explained in the docs I pointed previously: http://www.amibroker.com/guide/h_workspace.html Best regards, Tomasz Janeczko amibroker.com ----- Original Message ----- From: Ken Close <mailto:[EMAIL PROTECTED]> To: [email protected] Sent: Tuesday, July 08, 2008 1:46 PM Subject: [amibroker] More on Database Structure and Local Storage Can someone explain to me how I make the FastTrack database a local one? Background: I have had a FT db for years, with local storage disabled? I want to write to the OI field and preserve the written data. I checked "Enable Local Storage" but nothing different happened. Next, I tried to scan all symbols with a simple formula (I remembered having to do that years ago with a TC2000 database that came on a CD--I thought the same kind of step was needed.). Amibroker got hung on a single symbol and I had to End Program. AB would lock if I even clicked on this same symbol. Next, I created a new FastTrack database with a different name and copied over the appropriate files to the new DB folder. I enabled Local Storage from the start. All looked good. Except that writes to the OI field in the new DB would not save. I tried the scan all symbols trick again, and again it hung on the same symbol, certainly suggesting my FastTrack data itself is corrupt on that one symbol. (Special updates with the FastTrack data designed to correct problems did not seem to change anything.) My question is how do I get the FastTrack database to be local and to allow writes to the OI field to stick? My second question (as I assume I have to have the data in the Amibroker folders and not just in the FastTrack folders for the AB DB to be local), is how do I update the nightly downloads of new data which FastTrack will stick in their own file/folder? Thomasz, can you help? Thanks, Ken
