[fpc-pascal] Documentation for sqldb

John jszcmpr at netspace.net.au
Fri Jun 22 02:43:20 CEST 2007

Joost van der Sluis wrote:

> IN principle you can set ReadOnly to false and ParseSQL to true. That
> way sqldb tries to parse your query. If it's a simple 'select * from
> table' the TSQLQuery will be updateable. It automatically generates
> update/delete and insert queries. For the 'where' clause is uses  by
> default the primary key of the table. (That's a setting, upWhereKeyOnly)
> For example: 'delete * from table where pk=:old_pk'
> If you edit some data, those changes will be stored in an updatebuffer.
> With TSQLQuery.CancelUpdates all those changes are lost. But if you
> call .ApplyUpdates, it will execute one query for every changed record.
> (That could be a insert, update or delete query) 
So if I change some field values and post the record, that changed data 
goes into the update buffer - of TBufDataset ?  I should then be able to 
accumulate a few changes of these, and then, in code, call 
TSQLQuery.ApplyUpdate, and it should be sent to the database ?  Should 
this also commit at the database level, or do I have to do this ?  
(I think I tried this, but didn't pursue it very far, because I wasn't 
sure if it even should work)

Would it be feasible / sensible to call ApplyUpdate from an AfterPost 
event handler ?  

> Those are the basics. If you have questions, ask them here. And if you
> have any time, please document it somewhere on the wiki. ;)
I will, if I get to the point of thinking I understand it enough to not 
make a fool of myself!


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