I am playing with google app engine and having a bit of trouble on JDOQL queries. The example shows how to fetch stuff from the datastore: PersistenceManager pm = PMF.get().getPersistenceManager(); String query = "select from " + Greeting.class.getName(); List<Greeting> greetings = (List<Greeting>) pm.newQuery(query).execute(); But w...
I am trying to query the google datastore for something like (with pm --> persistanceManager): String filters = "( field == 'value' || field == 'anotherValue' )"; Query query = pm.newQuery(myType.class, filters); When I execute - I am getting back: App Engine datastore does not support operator OR. What's the best approach in peop...
On this question I solved the problem of querying Google Datastore to retrieve stuff by user (com.google.appengine.api.users.User) like this: User user = userService.getCurrentUser(); String select_query = "select from " + Greeting.class.getName(); Query query = pm.newQuery(select_query); query.setFilter("author == paramAuthor"); que...
According to the Queries and Indexes doc you can go a query effectively identically (so far as I can tell) to this: PersistenceManager pm = PMF.get().getPersistenceManager(); try { Query q = pm.newQuery(App.class); q.setOrdering("name desc"); try { results = (ArrayList<App>) q.execute(); } finally { q.closeAll(); } } finally {...
All examples I'm seeing show how to pull up entities matching a string exactly. Is there an equivalent to a LIKE query? Also, if it helps, I'm thinking of using the result for an auto-completing a text box. Thanks ...
I just started working on a project that will run on google app engine (GAE). I'm using java (wicket) with some ajax. I'm experienced with relational databases and typically use something like iBatis. When going through the docs and examples for the GAE datastore using JDO I see that they're executing stuff like: String query = "sele...
How do I escape parameters of queries in JDO (Google App Engine)? For example, how do I make the next snippet safe, if the variable name may contain unsafe chars as single quotes (') PersistenceManager pm = ...; String query = "select from Person where name='"+name+"'"; List<Shortened> shortened = (List<Shortened>) pm.newQuery(query).e...
I want to code a function to get a list of Entry objects whose date field is between a beginPeriod and endPeriod I post below a code snippet which works with a HACK. I have to substract a day from the begin period date. It seems the condition great or equal does not work. Any idea why I have this issue? public static List<Entry> getEnt...
I want to build an application where a user identified by an email address can have several application accounts. Each account can have one o more users. I am trying to use the JDO Storage capabilities with Google App Engine Java. Here is my attempt: @PersistenceCapable @Inheritance(strategy = InheritanceStrategy.NEW_TABLE) public class...
How to store java.util.Calendar field into one column with Datanucleus JDO. By default it is stored into two columns (millisecs, Timezone) with following JDO metadata. field name="startDate" serialized="true" embedded="true" persistence-modifier="persistent" What need to be changed in metadata to sto...
I have the next persistence capable classes: @PersistenceCapable public class AppAccount { @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) private Long id; @Persistent private String companyName; @Persistent List<AppUser> users = new ArrayList<AppUser>(); // Getters and Sett...
I have about 50k entities stored in appengine. I am able to look up an individual record via the GQL admin interface with a query like: SELECT * FROM Pet where __key__ = KEY( 'Pet','Fido') But I'm having trouble figuring out how to do a batch version of this via JDO. Right now I have this: PersistenceManager pm = ...; for(...
I'm working on a GAE app. I want to query datastore and retrieve all records between startDate and endDate. Each record has a datetime field. I'm using a query similar to this (the below code is something I quickly grabbed - I'm not near my developer machine.): Query query = pm.newQuery(Employee.class); query.setFilter("lastName == las...
The question pretty much says it all. If I have a class Class A public class A { ... private List<String> keys; ... } And I want to select all A instances from the DataStore that have atleast one of a List of keys, is there a better way of doing it than this: query = pm.newQuery(A.class); query.setFilter("keys.contains(:...
Following query gives a NullPointerException when complie it. Query query = pm.newQuery(Festival.class); query.setFilter("this.startDate == sDate"); query.declareImports("import java.util.GregorianCalendar"); query.declareParameters("GregorianCalendar sDate"); query.compile(); Class: public class Festival{ ... private G...
I am trying to create a database of users with connection between users (friends list). There are 2 main tables: UserEntity (main field id) and FriendEntity with fields: - initiatorId - id of user who initiated the friendship - friendId - id of user who has been invited. Now I am trying to fetch all friends of one particular user and ...
I have some records in datastore, I want to delete a specific record from the table. for example in SQL , we use delete * from table1 where name ="mike" what is the equivalent code in java (I m using Eclipse with Google appengine API plugin)? or any other method to do that? ...
Hi, I'm working with App Engine(Java/JDO) and are trying to do some querying with lists. So I have the following class: @PersistenceCapable(identityType = IdentityType.APPLICATION, detachable="true") public class MyEntity { @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) Key key; @Persistent List<Strin...
I'm using the .startsWith() filter in a JDOQL query but it's case sensitive. So startsWith("ab") doesn't return "Abc" result and so on. Will I need to use a SQL query to avoid this ? ...
When querying with JDOQL is there a performance difference between using the declarative version and the Single-String version: Example from the JDOQL doc: //Declarative JDOQL : Query q = pm.newQuery(org.jpox.Person.class, "lastName == \"Jones\" && age < age_limit"); q.declareParameters("double age_limit"); List results = (List)q.execu...