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From vd <vineetdan...@gmail.com>
Subject Re: How to write WHERE .. LIKE query ?
Date Tue, 11 May 2010 06:36:28 GMT
Hi Mike

AFAIK cassandra queries only on keys and not on column names, please verify.



On Tue, May 11, 2010 at 11:06 AM, Mike Malone <mike@simplegeo.com> wrote:
>
>
> On Mon, May 10, 2010 at 9:00 PM, Shuge Lee <shuge.lee@gmail.com> wrote:
>>
>> Hi all:
>> How to write WHERE ... LIKE query ?
>> For examples(described in Python):
>> Schema:
>> # columnfamily name
>> resources = [
>>    # key
>>     'foo': {
>>         # columns and value
>>         'url': 'foo.com',
>>         'pushlier': 'foo',
>>     },
>>     'oof': {
>>         'url': 'oof.com',
>>         'pushlier': 'off',
>>     },
>>    #  ... ,
>> }
>> # this is very easy,
>> SELECT * FROM KEY = 'foo'
>> but following are really hard:
>> SELECT * FROM resources WHERE key LIKE 'o%' # get all records which key
>> name contains character 'o'?
>
> get_range_slices(<keyspace>, ColumnParent(column_family),
> SlicePredicate(slice_range=SliceRange('',''), KeyRange('o', 'o~'),
> ConsistencyLevel.ONE);
>
>>
>> SELECT * FROM resources WHERE url == 'oof.com'
>
> This is a projection. Cassandra doesn't support this sort of query out of
> the box. You'll have to structure your data so that data you want to query
> by is in the key or column name. Or you'll have to manually build secondary
> indexes.
>
> Mike
>

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