Transactions, Commits and Rollbacks

[Joseph Morgan]

In the past I would manually do this in Xojo code (iterate through cursors). And that would have been my suggestion but I imagine foreign key links would be faster now. 

But, How is the foreign key thing done. I have checked the wiki and attempted in vstudio but it's not working. 

> On Oct 12, 2013, at 1:17 AM, Ruslan Zasukhin <ruslan_zasukhin at valentina-db.com> wrote:
> 
> On 10/12/13 7:51 AM, "Ivan Smahin" <ivan_smahin at paradigmasoft.com> wrote:
> 
>>> Just an example would be: If I had a database that had invoices in it and I
>>> want to delete all the records from the database
>>> for year 1980. The invoices are stored in one table and each line item on the
>>> invoice is stored in another table. I need to be
>>> sure that when an invoice is deleted the line items for that invoice are also
>>> deleted. Of course the key for each invoice is stored as a field
>>> in the invoice items table to perform the delete on.
>>> 
>>> This is easily done with transactions, but I'm kind of clueless right now of
>>> the best way to achieve it with Valentina.
>>> 
>>> I wonder if a delete trigger might work reliably?
>>> 
>>> Any help or ideas you may have are much appreciated.
>>> 
>>> I don't usually need this type of query often, but when this type of task is
>>> needed it is usually deleting many records.
>> 
>> 
>> You have few ways to do it.
>> 1. You can use link's cascade deleting feature.
> 
> I'd say this is the best way to have integrity of links.
> 
> 
> ====
> SQLite many years did use triggers to provide integrity of FKs,
> But this was only because there was no Foreign Keys.
> In 3.x of SQLite was added FK, and it should be used also instead of
> triggers.
> 
> Triggers should be avoided if possible,
> They work like invisible daemons :-)
> 
> 
>> 2. OnDelete triggers.
>> 3. Stored procedure way - to make any complex operation "atomic".
>> 
>> All of that ways are common for almost any RDBMS.
>> It is not directly related to transactions.
> 
> -- 
> Best regards,
> 
> Ruslan Zasukhin
> VP Engineering and New Technology
> Paradigma Software, Inc
> 
> Valentina - Joining Worlds of Information
> http://www.paradigmasoft.com
> 
> [I feel the need: the need for speed]
> 
> 
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