jdo_开发者

InvocationTargetException: Plugin (Bundle) "org.datanucleus" is already registered

I am trying to follow the DataNucleus tutorial for JDO. I am using Maven and I have followed the instructions available here for the enhancer.[详细]

2023-04-11 17:47 分类：问答

Google App Engine JDO Query using Alternate logic for 'NOT IN'

I\'m developing a Googl开发者_开发问答e App Engine Java app where users can search business objects from database based on search criteria.[详细]

2023-04-09 05:27 分类：问答

JDO on GoogleAppEngine: How to efficiently retrieve a subset of fields from a huge number of records

I\'m facing a little problem of scalabi开发者_高级运维lity. I\'m using JDO to query my datastore.[详细]

2023-04-05 15:07 分类：问答

JDO on GoogleAppEngine: How to count and group with BigTable

I need to collect some statistics on my entities in the datastore. As an example, I need to know how many objects of a kind I have, how[详细]

2023-04-05 06:12 分类：问答

Adding functions to my Google app engine app made with Java and JDO

Here is my testing app: http://caoscoding.appspot.com login: admin pass: test Is an simple app where you insert some data and get开发者_如何学JAVA out a table, of that data, that\'s all.[详细]

2023-04-04 14:50 分类：问答

JDO + PostgreSQL Arrays

I\'ve implemented store_mapping extension but it currently uses ObjectAsStringMapping. As a result I can read array values from database but any insert or update causes underlying postgresql driver er[详细]

2023-04-04 08:34 分类：问答

How can I get the ID/Name of an entry using datastore

When I look under http://localhost:8888/_ah/admin/ I can see that every entry in datastore has an ID/Name field. I also know that I can get objects with this id using persistenceManager.getObject(claz[详细]

2023-04-04 08:07 分类：问答

Does High Replication DB "eventually consistent" mean that detached JDO objects may not always contain updated object graph?

I have been using the Master/Slave database for previous App Engine projects but my new app is defined as High Replication Datastore (I don\'t believe this setting can be changed after it is defined).[详细]

2023-04-02 14:16 分类：问答

Datanucleus exception adding new column to hbase table

I am using DataNucleus with HBase. I had a table user. It contained 4 rows. Now I added a new column to the table. Now everytime I access any old user object which does not have this column DataNucleu[详细]

2023-04-01 19:02 分类：问答