Remote SQL databases

Bob Sneidar bobs at twft.com
Mon May 24 16:58:27 CDT 2010


Hi Mark and all interested parties.

Perhaps I failed to mention that the two databases do not know about each other. The SQL server doing the join has no access to the file based SQLite database it is doing a join against. I am pretty sure this is impossible to do like this. 

It's okay though because I thought of another method for accomplishing this. If I query the table I am importing data from for the key column data, I can create a query of records in the destination database for the same keys. I can then compare both results, and the source keys that I do not find in the destination keys I can insert into the destination database before I go on and do my real data updating. 

Another facet of this is that I want the Data Import/Merge feature to be highly scalable, so I am building in paging. I want to be able to use this functionality and also to make it available to others as a standalone stack or app in the future. 

I need to know the limits of Revolution when it comes to doing SQL queries. How big a data set, in terms of bytes of data, do you think would be the most I should have in my page size? I wonder if anyone on the list has ever really pushed the limits of Revolution data sets? I know it depends on how much memory Revolution has access to, because queries are returned as read only memory based data, and the conversion to a text string would effectively double that. 

Bob


On May 21, 2010, at 5:04 PM, Mark Stuart wrote:

> Hi Bob,
> on Fri May 21 17:31:53 CDT 2010, Bob Sneidar wrote: 
>>> 
> So now I have to think about using joins.
> <<
> Just preface the table name that's in the other database with the
> database_alias_name.table_name:
> 
> SELECT cus.Customer_Number, cus.Customer_Name, ctyp.Customer_Type_Name
> FROM database1.customers AS cus LEFT OUTER JOIN
> database2.customer_types as ctyp ON cus.Customer_Type =
> ctyp.Customer_Type_ID
> 
> HTH,
> Mark Stuart
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