Jesse, So your row have a primary key and some other unique identifier derived other attributes.
If the compound key is a combinaison of full attribute values, you cana a compound unique key in the database. CREATE UNIQUE INDEX ON Table (col1, col2, ..., coln) If it is from partial values, the most reliable way is to add a string column with the computed key with it's unique constraint. If you already have duplicate, you can add a method in the migration to resolve them before adding the constraint or do it manually... Regards, Samuel > Le 22 nov. 2021 à 09:27, Jesse Tayler <jtay...@oeinc.com> a écrit : > > It’s likely just a unique constraint perhaps. > > It’s not UIDs or primary keys it’s a unique row type based on a couple > strings where there should be only one, and that one should last forever. > > There’s an API where calls can come in basically at the same time and instead > of fetching first to see if the object exists, I should likely respond to an > SQL error rejecting a new row and then fetch and return that existing object > based on that error condition. > > I’d suppose the database is the best place for that policy, but I don’t think > I’ve implemented constraints quite like that before so I’d need to write some > sort of Migrations for it if it’s to be reliable in all those situations > where it might encounter duplicate data…hmmm… > > > > >> On Nov 22, 2021, at 8:59 AM, Samuel Pelletier <sam...@samkar.com> wrote: >> >> Hi Jesse, >> >> Your question may have multiple answers, can you describe the contexts and >> duplicate sources you fear ? >> >> Is the primary key generated by the WO app or it is external (like a GUID) ? >> >> Do you have a secondary identifier that should be unique ? >> >> Anyway, you should add constraint in to the database if uniqueness is >> required (this apply to all frameworks in all language) >> >> If you use EOF primary key generation, you should not have problems with >> duplicate keys. If you require high throughput, using UUID primary key or >> implementing a custom generator will help by saving round trips to the >> database server. If you insert in batch, it will be also faster than >> individual inserts. >> >> Regards, >> >> Samuel >> >>> Le 22 nov. 2021 à 08:34, Jesse Tayler via Webobjects-dev >>> <webobjects-dev@lists.apple.com> a écrit : >>> >>> I asked on slack but I figured I’d ping the list >>> >>> Who has a good way to ensure a serial EO creation queue when the system >>> could be hit really fast and you must avoid duplicate entries? >>> >>> I’m a bit surprised I don’t recall EOF style solutions for such things and >>> maybe the Amazon RDS database has a shared connection pattern the apps can >>> use, I didn’t see anything so I figure this is application level stuff. >>> >>> Thoughts? Suggestions? >>> _______________________________________________ >>> Do not post admin requests to the list. They will be ignored. >>> Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) >>> Help/Unsubscribe/Update your Subscription: >>> https://lists.apple.com/mailman/options/webobjects-dev/samuel%40samkar.com >>> >>> This email sent to sam...@samkar.com >> > _______________________________________________ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
