Just wanted to say that I see that what I'm trying to do is just
fundamentally wrong and will decidedly cause serious problems in the
longer term. I suppose it is best to check for uniqueness in the
service layer.
On Feb 24, 12:05 pm, atomi <at...@verizon.net> wrote:
> I've been trying to devise a way to maintain uniqueness among different
> entities by storing some kind of UUID based on the fields I want unique for
> that entity Using JDO, and a GenericDAO (groovy)
> Here is the method for put() in my GenericDAO:
>
> def put(Object object) {
> Collection objects = list();
> Boolean exists = false;
>
> objects.each {if(it.getUniqueKey() == object.getUniqueKey()) {exists =
> true}}
>
> if(!exists) {
> PersistenceManager pm = getPersistenceManager();
>
> Transaction tx = pm.currentTransaction();
> try {
> tx.begin();
> pm.makePersistent(object);
> tx.commit();} finally {
>
> if (tx.isActive()) {
> tx.rollback();}
> pm.close();
> }
> }
>
> }
> Where the uniqueKey field is a *unique string based on fields I need to be
> unique*.
> My question is what is good way to create this unique key string using for
> example multiple string fields that will be consistent? My first inclination
> was to use an MD5 but I see that datanucleus provides value generators that
> might work better? Ideas? Or am I just going about this the wrong way?
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