Ok, don't worry, that's what we are here for.
on the other hand, remember the two types of associations in DataStore, the
"owned" and "not owned" related to the way the Primary Keys are stored as
foreign Keys in other Entities to simulate the Relational way.
The concept is a bit complex when trying to understand it, but once you've
got it, you are done!.
GAE & DataStore Rule! jeje.
Rgds.
any doubt, I'm always available.
Ronmell F.
2010/8/12 Caram <caram.jun...@gmail.com>
> Sorry for indelicate, I researched, tried, and nothing illuminate my
> way...
>
> But, MAN! I got it! :) Thanks for the explanation!!! :)
>
> I would now look for:
> 1) If I can use a Key like you said but with a Key that is a number
> generated automatically.
> 2) If 1 above not possible, how I can map foreign keys and control the
> associations.
>
> I would research!
>
> THANKS!
> Caram.:
>
>
> On 12 ago, 13:24, Ronmell Fuentes <ringe...@gmail.com> wrote:
> > *Hi *Caram it's good to say hi to you again... jeje Just Kidding.
> >
> > yup, you are generating an automatic ID, but that's why there is double
> > records, because there is for instance 2 differents IDs for the same
> > records. I mean:
> >
> > let's suppose the initial data in your data store is like following:
> > *ID name desc.*
> > 1. hello whatever.
> >
> > but if you try to upload the same data in an CSV file, like this.
> >
> > *name desc.*
> > hello whatever
> > hello whatever1.
> >
> > after uploading the file the data in datastore would be something like
> this.
> >
> > *ID name desc.*
> > 1. hello whatever.
> > 2. hello whatever.
> > 3. hello whatever1.
> >
> > because the ID, is been generated every time that an insert occurs.
> >
> > If you want to avoid this, you can add something to the Constructor of
> the
> > class to manage this. For example:
> >
> > *public Login(String user, String password) {
> > Key key =
> KeyFactory.createKey(Login.class.getSimpleName(),
> > user);
> > this.user = user;
> > this.password = password;
> > }*
> >
> > This will make the following:
> >
> > when inserting for the first time the data:
> > user: "hello"
> > pass: "world"
> >
> > the Datastore would be like this.
> >
> > *Key user password.*
> > Login("hello") hello world.
> >
> > then when uploading new data from CSV, smthg like this.
> >
> > hello newworld
> > hello2 world2
> > hello3 world3
> >
> > the data store would be like this.
> >
> > *key user password.*
> > Login("hello") hello newworld
> > Login("hello2") hello2 world2
> > Login("hello3") hello3 world3
> >
> > As you can see, in the user "hello" the data was just update, so there's
> no
> > double records, but the others are inserted as new ones.
> > this happens because the Key of your Entity is generated depending on the
> > user, and since the Key is unique, when making "MakePersistenceAll()" the
> > Data just is written over the previous data, if there is already a record
> > with the same Key, then data is updated, otherwise is inserted.
> >
> > Hope this was helpful.
> >
> > Rgds.
> >
> > R. F
> >
> > 2010/8/12 Caram <caram.jun...@gmail.com>
> >
> >
> >
> > > I'm confused.
> >
> > > My class Login of persistence is:
> > > ---------------------------------------------------------------
> > > import javax.jdo.annotations.IdGeneratorStrategy;
> > > import javax.jdo.annotations.PersistenceCapable;
> > > import javax.jdo.annotations.Persistent;
> > > import javax.jdo.annotations.PrimaryKey;
> >
> > > @PersistenceCapable
> > > public class Login {
> >
> > > @PrimaryKey
> > > @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
> > > private Long id;
> >
> > > @Persistent
> > > private String user;
> >
> > > @Persistent
> > > private String password;
> >
> > > public String getUser() {
> > > return user;
> > > }
> >
> > > public void setUser(String user) {
> > > this.user = user;
> > > }
> >
> > > public String getPassword() {
> > > return password;
> > > }
> >
> > > public void setPassword(String password) {
> > > this.password = password;
> > > }
> >
> > > }
> >
> > >
> ---------------------------------------------------------------------------
> ------
> >
> > > So, I'm storing the Entity and automatic generating the ID. Right? If
> > > true, my data should not double as is happening, right?
> >
> > > Thank you very much!
> >
> > > Rgds,
> > > Caram.:
> >
> > > On 11 ago, 18:38, Ronmell Fuentes <ringe...@gmail.com> wrote:
> > > > yup, just in case the ID is not generated when storing the Entity.
> > > > ;-)
> > > > otherwise the ID 'd be generated every time the data'd be stored.
> >
> > > > 2010/8/11 Caram <caram.jun...@gmail.com>
> >
> > > > > But, in
> > > > >
> http://code.google.com/intl/en/appengine/docs/python/tools/uploadingd.
> > > ..
> > > > > ,
> > > > > he said:
> >
> > > > > "When data is downloaded, the entities are stored along with their
> > > > > original keys. When the data is uploaded, the original keys are
> used.
> > > > > If an entity exists in the datastore with the same key as an entity
> > > > > being uploaded, the entity in the datastore is replaced.
> >
> > > > > You can use upload_data to replace the data in the app from which
> it
> > > > > was dumped, or you can use it to upload the data to a different
> > > > > application. Entities with numeric system IDs will be uploaded with
> > > > > the same IDs, and reference properties will be preserved."
> >
> > > > > So, my ID of Login is Long, I understand that it should be updating
> > > > > like he said above and not adding as is happening.
> >
> > > > > Am I right?
> >
> > > > > Thanks!
> > > > > Caram.:
> >
> > > > > On 11 ago, 15:57, Ronmell Fuentes <ringe...@gmail.com> wrote:
> > > > > > Hi, ok.
> > > > > > what happens is the following.
> >
> > > > > > As you already know, in DataStore there's no "update" because
> when
> > > you
> > > > > > insert a record, depending on the Primary Key you have set in
> your,
> > > all
> > > > > the
> > > > > > new data just falls over the first records. This means, that if
> you
> > > are
> > > > > > generating an ID every time an insert is done, this will keep
> until
> > > > > always.
> > > > > > jeje. But if for example you set a primary Key based on an field
> of
> > > your
> > > > > > entity, for example you set
> > > > > > Primary Key(MyField); where MyField is a string name, this will
> > > create
> > > > > > something like this.
> > > > > > For MyField="helloworld1";
> >
> > > > > > MyEntity("helloworld1");
> >
> > > > > > For MyField="helloworld2";
> >
> > > > > > MyEntity("helloworld1");
> >
> > > > > > and so on...
> >
> > > > > > So that, the main point here is, when inserting a new record, and
> the
> > > > > value
> > > > > > of the Primary Key is not set by yourself, this will
> automatically
> > > create
> > > > > a
> > > > > > new record. All data will be inserted again and again.
> >
> > > > > > if you already have the ID=1;
> > > > > > and you try to insert a new record with ID=1 and ID is the
> primary
> > > key,
> > > > > then
> > > > > > the record won't be inserted again, but will be updated.
> >
> > > > > > As you can see, all depends on the way you create your Entities
> or
> > > > > Classes .
> >
> > > > > > Rgds.
> >
> > > > > > R. F.
> >
> > > > > > 2010/8/11 Caram <caram.jun...@gmail.com>
> >
> > > > > > > Ronmell,
> >
> > > > > > > These days I study and I succeed in download data from
> datastore
> > > > > > > in .csv.
> > > > > > > I understand that I can modifiy this .csv and upload it to make
> the
> > > > > > > changes in my datastore. But, when I try to upload it,
> duplicate in
> > > my
> > > > > > > datastore all entities I have. It changes the ID to name, I've
> > > tried
> > > > > > > many things unsuccessfully, can you help me?
> >
> > > > > > > Here my commands/codes:
> >
> > > > > > > bulkloader.yaml:
> >
> > >
> ---------------------------------------------------------------------------
> > > > > --------------
> > > > > > > # Autogenerated bulkloader.yaml file.
> > > > > > > # You must edit this file before using it. TODO: Remove this
> line
> > > when
> > > > > > > done.
> > > > > > > # At a minimum address the items marked with TODO:
> > > > > > > # * Fill in connector and connector_options
> > > > > > > # * Review the property_map.
> > > > > > > # - Ensure the 'external_name' matches the name of your CSV
> > > column,
> > > > > > > # XML tag, etc.
> > > > > > > # - Check that __key__ property is what you want. Its value
> will
> > > > > > > become
> > > > > > > # the key name on import, and on export the value will be
> the
> > > Key
> > > > > > > # object. If you would like automatic key generation on
> > > import
> > > > > > > and
> > > > > > > # omitting the key on export, you can remove the entire
> > > __key__
> > > > > > > # property from the property map.
> >
> > > > > > > # If you have module(s) with your model classes, add them here.
> > > Also
> > > > > > > # change the kind properties to model_class.
> > > > > > > python_preamble:
> > > > > > > - import: base64
> > > > > > > - import: re
> > > > > > > - import: google.appengine.ext.bulkload.transform
> > > > > > > - import: google.appengine.ext.bulkload.bulkloader_wizard
> > > > > > > - import: google.appengine.api.datastore
> > > > > > > - import: google.appengine.api.users
> >
> > > > > > > transformers:
> >
> > > > > > > - kind: Login
> > > > > > > connector: csv
> >
> > > > > > > property_map:
> > > > > > > - property: __key__
> > > > > > > external_name: ID
> > > > > > > export_transform: transform.key_id_or_name_as_string
> >
> > > > > > > - property: password
> > > > > > > external_name: password
> >
> > > > > > > - property: user
> > > > > > > external_name: user
> >
> > >
> ---------------------------------------------------------------------------
> > > > > ----------------------------------
> >
> > > > > > > For download:
> > > > > > > appcfg.py download_data -e caram.jun...@gmail.com --
> > > > > > > config_file=bulkloader.yaml --kind=Login --filename=teste.csv
> --
> > > > > > > url=http://pac-web.appspot.com/remote_api
> >
> > > > > > > Result (teste.csv):
> >
> > >
> ---------------------------------------------------------------------------
> > > > > -------------------------------
> > > > > > > password,ID,user
> > > > > > > swdw,1,User
> > > > > > > CARACA,1001,User
> > > > > > > CARACA2,2001,User
> > > > > > > ,3001,
> > > > > > > edsed,4001,User
> > > > > > > edsed,4002,User43
> > > > > > > edsed,5001,User43
> > > > > > > edsed,6001,User47
> >
> > >
> ---------------------------------------------------------------------------
> > > > > -------------------------------
> >
> > > > > > > For upload (result inhttps://appengine.google.com/datastore,
> kind
> > > > > > > Login):
> >
> > >
> ---------------------------------------------------------------------------
> > > > > -------------------------------
> > > > > > > ID/Name password user
> > > > > > > id=1 swdw User
> > > > > > > id=1001 CARACA User
> > > > > > > id=2001 CARACA2 User
> > > > > > > id=3001 <null> <null>
> > > > > > > id=4001 edsed User
> > > > > > > id=4002 edsed User43
> > > > > > > id=5001 edsed User43
> > > > > > > id=6001 edsed User47
> > > > > > > name=1 swdw User
> > > > > > > name=1001 CARACA User
> > > > > > > name=2001 CARACA2 User
> > > > > > > name=3001
> > > > > > > name=4001 edsed User
> > > > > > > name=4002 edsed User43
> > > > > > > name=5001 edsed
> >
> > ...
> >
> > mais »
>
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