CODEWITHSUNDEEP
javagoogle-app-enginejdo
nwaltham
nwaltham

Reputation: 2074

On Google App Engine is it possible JDOQL Date without using a parameterised query?

Is it possible to do a date query in JDOQL without using a parameterrised query on Google App Engine.

I am trying to write some generic code that looks something like this, where criteria is just a string, and I would like to be able to specify anything - with this piece of code not needing to to know much about the underlying data. 

Query query = pm.newQuery(tClass);
        if (criteria!=null) {
            query.setFilter(criteria);
        }

criteria could be "startdate = 'someproperlyformatteddatetime'"

Thanks for your suggestions.

Upvotes: 0

Views: 71

Answers (1)

Peter Knego
Peter Knego

Reputation: 80340

Of course, GAE JDO queries support JDOQL. You could simply do something like this: q.setFilter("height <= 200") or q.setFilter("name == 'Smith'"), where you would programmatically assemble the JDOQL filter string. The only downside is that you need to know the type of parameters (as saved in Datastore), as strings need to be enclosed in single or double quotes.

Note that all restrictions on queries still apply.

Also, if you want to query on multiple properties where you also use inequality operator, then you need to define compound indexes beforehand.

Update: JDOQL literal parameter specification works with string and numeric values; all other value types must use parameter substitution. You could still do that programmatically.

Another workaround would be if you use long instead of Date and convert dates to UNIX timestamps (which are of type long).

Upvotes: 1

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