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POGoogle Datastore problem with query on *User* type
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933023
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2009-05-31T22:28:27.450
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2010-07-21T19:37:30.420
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2017-05-23T12:32:06.453
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Body
On <a href="https://stackoverflow.com/questions/764337/how-to-fetch-data-by-user-from-google-datastore">this</a> question I solved the problem of querying Google Datastore to retrieve stuff by user (com.google.appengine.api.users.User) like this: <pre><code>User user = userService.getCurrentUser(); String select_query = "select from " + Greeting.class.getName(); Query query = pm.newQuery(select_query); query.setFilter("author == paramAuthor"); query.declareParameters("java.lang.String paramAuthor"); greetings = (List<Greeting>) query.execute(user); </code></pre> The above works fine - but after a bit of messing around I realized this syntax in not very practical as the need to build more complicated queries arises - so I decided to manually build my filters and now I got for example something like the following (where the filter is usually passed in as a string variable but now is built inline for simplicity): <pre><code>User user = userService.getCurrentUser(); String select_query = "select from " + Greeting.class.getName(); Query query = pm.newQuery(select_query); query.setFilter("author == '"+ user.getEmail() +"'"); greetings = (List<Greeting>) query.execute(); </code></pre> Obviously this won't work even if this syntax with <code>field = 'value'</code> is <a href="http://code.google.com/appengine/docs/java/datastore/queriesandindexes.html" rel="nofollow noreferrer">supported by JDOQL</a> and it works fine on other fields (String types and Enums). The other strange thing is that looking at the Data viewer in the app-engine dashboard the 'author' field is stored as type User but the value is 'user@gmail.com', and then again when I set it up as parameter (the case above that works fine) I am declaring the parameter as a String then passing down an instance of User (user) which gets serialized with a simple <code>toString()</code> (I guess). Anyone any idea?
Tags
<google-app-engine><jdo><google-cloud-datastore><jdoql>
Title
Google Datastore problem with query on *User* type
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