Hi Dave,
Thanks for your answer and sorry for the late reply.
> In the first "filter" line... do you just want to filter out the
> LimitOrders that do not have the same tradeType foreign key reference
> as the FK of the parameter that you pass in?
Yes, that's part of the filtering, but I need to do more stuff.
>
> Can you post the model opens (the LimitOrder and the other stuff) as
> well as the logic?
I gonna do some more thinking about the logic, and paste the source later.
>
> For example,
>
> LimitOrderMetaObj.find(By(LimitOrderMetaObj.id,remainingOrders(i).id)).map(_.status.set("OPEN"))
>
> openOr 0L
>
> I'm not sure why you're doing a map and an openOr 0L... you're not
> returning an expression.
This was the only way I knew to do that......but probably the wrong
one.....8-)
>
> Also, I'm not sure why you are loading an instance out of the RDBMS in
> order to to set the status to "OPEN" and then just discard the
> instance. Does the set method on the status open have some side
> effect that you've coded?
It was the first approach to implement the logic and since I'm still not
very close with Lift, some ugly code came out.
>
> If you want to load a bunch of records, update fields on those
> records, and save the records, I'd like to suggest the following code:
That's really helpful, I try to use that to get a better implementation!
>
> class Dog extends LongKeyedMapper[Dog] with IdPK {
> def getSingleton = Dog
>
> object name extends MappedPoliteString(this, 128)
> object weight extends MappedInt(this)
> }
>
> object Dog extends Dog with LongKeyedMetaMapper[Dog]
>
> class MyStuff extends LongKeyedMapper[MyStuff] with IdPK {
> def getSingleton = MyStuff
>
> object info extends MappedString(this, 128)
> object count extends MappedInt(this)
> object dog extends MappedLongForeignKey(this, Dog)
> }
>
>
> object MyStuff extends MyStuff with LongKeyedMetaMapper[MyStuff] {
> def mutate(in: MyStuff) {
> for {
> // find all the items where info = 'NEW' and dog != the value of
> in's dog field
> item <- MyStuff.findAll(By(MyStuff.info, "NEW"),
> NotBy(MyStuff.dog, in.dog))
> // increment the count field, update the info field and save
> } item.count(item.count + 1).info("Not so NEW").save
> }
> }
>
>
thanks!
>
>
> On Wed, Jul 22, 2009 at 4:05 PM, Hannes <[email protected]
> <mailto:[email protected]>> wrote:
>
>
> I kind of found the problem. So far, it has nothing to do with save or
> anything like that. The problem is that this line:
>
> val newOrders = LimitOrderMetaObj.findAll(By(LimitOrderMetaObj.status,
> "NEW")).toList.filter(o2 => o2.tradeType.name
> <http://o2.tradeType.name> != o1.tradeType.name
> <http://o1.tradeType.name>)
>
> does not compare the "name" of the tradetype (TradeType has an own
> "name" field) in the filter method, instead "name" returns "tradetype"
> (is this the object name?). The thing is, because its a foreign key
> reference and as you told me, it needs to be accessed via
>
> o.tradeType.obj.map(_.name.is <http://name.is>) openOr ""
>
> But now, when I want to compare two of those TradeType.name field
> (which
> are normal strings) I don't really know how to do it. I tried
> something
> like that, but it doesn't work:
>
> val newOrders = LimitOrderMetaObj.findAll(By(LimitOrderMetaObj.status,
> "NEW")).toList.filter(o2 => {o2.tradeType.obj.map(_.name.is
> <http://name.is>) openOr ""}
> != {o1.tradeType.obj.map(_.name.is <http://name.is>) openOr "")
>
>
> thanks.
>
> > Howdy,
> >
> > You can save some memory by using findMap:
> >
> > def joinOrders(o1: LimitOrder): Unit = {
> > /* select all orders where status=NEW and where that.tradeType !=
> > order1.tradeType */
> > val newOrders =
> > LimitOrderMetaObj.findMap(By(LimitOrderMetaObj.status, "NEW")){o2 =>
> > Full(o2).filter(o2.tradeType.name <http://o2.tradeType.name>
> <http://o2.tradetype.name/> !=
> > o1.tradeType.name <http://o1.tradeType.name>
> <http://o1.tradetype.name/>)}
> >
> > findMap applies the filtering operation as each row is pulled
> from the
> > RDBMS... so you'll have fewer objects in memory.
> >
> > In terms of the remaining logic... I'm a little lost in your code...
> > can you describe the logic? What gets updated under which
> conditions?
> >
> >
> > On Wed, Jul 22, 2009 at 5:35 AM, Hannes <[email protected]
> <mailto:[email protected]>
> > <mailto:[email protected] <mailto:[email protected]>>> wrote:
> >
> >
> > Hi Lifters,
> >
> > It seems like I'm having problems to modify items that are
> already in
> > the database. What I do is, first find the item, then set a new
> > value to
> > it and then save it. So far so good, or?
> >
> > Because its a expensive filter process to find those items to
> > modify, I
> > made a local copy of the sub-list that contains the most
> interesting
> > items. This sub-list is processed further on and when I
> finally know
> > which items to modify, I look those ones up in the database
> again and
> > set the values. I hope it makes sence...
> >
> > thanks
> >
> > Here's the code:
> >
> > def joinOrders(o1: LimitOrder): Unit = {
> > /* select all orders where status=NEW and where
> that.tradeType !=
> > order1.tradeType */
> > val newOrders =
> > LimitOrderMetaObj.findAll(By(LimitOrderMetaObj.status,
> > "NEW")).toList.filter(o2 => o2.tradeType.name
> <http://o2.tradeType.name>
> > <http://o2.tradeType.name> != o1.tradeType.name
> <http://o1.tradeType.name>
> > <http://o1.tradeType.name>)
> >
> > def decideByTradeType: List[LimitOrder] = {
> > /* keep all orders where that.marketPoint <=
> order1.marketPoint
> > * sort the list from lowest to highest marketPoint */
> > if (o1.tradeType.name <http://o1.tradeType.name>
> <http://o1.tradeType.name> == "BUY")
> > newOrders.filter(o2 => o2.marketPoint.is
> <http://o2.marketPoint.is>
> > <http://o2.marketPoint.is> <=
> > o1.marketPoint.is <http://o1.marketPoint.is>
> <http://o1.marketPoint.is>).sort((s, t) =>
> > s.marketPoint.is <http://s.marketPoint.is>
> <http://s.marketPoint.is> < t.marketPoint.is <http://t.marketPoint.is>
> > <http://t.marketPoint.is>)
> > /* keep all orders where that.marketPoint >=
> order1.marketPoint
> > * sort the list from highest to lowest marketPoint */
> > else //because there are only two different types!
> Its the same
> > as: if (o1.tradeType.name <http://o1.tradeType.name>
> <http://o1.tradeType.name> == "SELL")
> > newOrders.filter(o2 => o2.marketPoint.is
> <http://o2.marketPoint.is>
> > <http://o2.marketPoint.is> >=
> > o1.marketPoint.is <http://o1.marketPoint.is>
> <http://o1.marketPoint.is>).sort((s, t) =>
> > s.marketPoint.is <http://s.marketPoint.is>
> <http://s.marketPoint.is> > t.marketPoint.is <http://t.marketPoint.is>
> > <http://t.marketPoint.is>)
> > }
> >
> > var i = 0
> > var done = false
> > val remainingOrders = decideByTradeType
> > while (i < remainingOrders.length && !done) {
> > if (remainingOrders(i).lots == o1.lots) {
> > LimitOrderMetaObj.find(By(LimitOrderMetaObj.id,
> > remainingOrders(i).id)).map(_.status.set("OPEN")) openOr 0L
> > LimitOrderMetaObj.find(By(LimitOrderMetaObj.id,
> > remainingOrders(i).id)).map(_.save) openOr 0L
> > LimitOrderMetaObj.find(By(LimitOrderMetaObj.id,
> > o1.id <http://o1.id>
> <http://o1.id>)).map(_.status.set("OPEN")) openOr 0L
> > LimitOrderMetaObj.find(By(LimitOrderMetaObj.id,
> > o1.id <http://o1.id> <http://o1.id>)).map(_.save) openOr 0L
> > done = true
> > }
> > if (remainingOrders(i).lots.is <http://lots.is>
> <http://lots.is> <
> > o1.lots.is <http://o1.lots.is> <http://o1.lots.is>) {
> > LimitOrderMetaObj.find(By(LimitOrderMetaObj.id,
> > remainingOrders(i).id)).map(_.status.set("OPEN")) openOr 0L
> > LimitOrderMetaObj.find(By(LimitOrderMetaObj.id,
> > remainingOrders(i).id)).map(_.save) openOr 0L
> > LimitOrderMetaObj.find(By(LimitOrderMetaObj.id,
> > o1.id <http://o1.id>
> <http://o1.id>)).map(_.lots.set(o1.lots.is <http://o1.lots.is>
> > <http://o1.lots.is> - remainingOrders(i).lots.is
> <http://lots.is>
> > <http://lots.is>)) openOr 0L
> > LimitOrderMetaObj.find(By(LimitOrderMetaObj.id,
> > o1.id <http://o1.id> <http://o1.id>)).map(_.save) openOr 0L
> > }
> > if (remainingOrders(i).lots.is <http://lots.is>
> <http://lots.is> >
> > o1.lots.is <http://o1.lots.is> <http://o1.lots.is>) {
> > LimitOrderMetaObj.find(By(LimitOrderMetaObj.id,
> > o1.id <http://o1.id>
> <http://o1.id>)).map(_.status.set("OPEN")) openOr 0L
> > LimitOrderMetaObj.find(By(LimitOrderMetaObj.id,
> > o1.id <http://o1.id> <http://o1.id>)).map(_.save) openOr 0L
> > LimitOrderMetaObj.find(By(LimitOrderMetaObj.id,
> >
> remainingOrders(i).id)).map(_.lots.set(remainingOrders(i).lots.is
> <http://lots.is>
> > <http://lots.is> -
> > o1.lots.is <http://o1.lots.is> <http://o1.lots.is>)) openOr 0L
> > LimitOrderMetaObj.find(By(LimitOrderMetaObj.id,
> > remainingOrders(i).id)).map(_.save) openOr 0L
> > done = true
> > }
> > i = i + 1
> > }
> > }
> >
> >
> >
> >
> >
> > --
> > Lift, the simply functional web framework http://liftweb.net
> > Beginning Scala http://www.apress.com/book/view/1430219890
> > Follow me: http://twitter.com/dpp
> > Git some: http://github.com/dpp
> >
> > >
>
>
>
>
>
>
> --
> Lift, the simply functional web framework http://liftweb.net
> Beginning Scala http://www.apress.com/book/view/1430219890
> Follow me: http://twitter.com/dpp
> Git some: http://github.com/dpp
>
> >
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