In the future, maybe cassandra can provide some "Filter" or "Coprocessor"
interfaces. Just like what of Bigtable do.
But now, cassandra is too young, there are many things to do for a clear
core.
On Tue, May 11, 2010 at 11:35 PM, Mike Malone <m...@simplegeo.com> wrote:
> On Mon, May 10, 2010 at 11:36 PM, vd <vineetdan...@gmail.com> wrote:
>
>> Hi Mike
>>
>> AFAIK cassandra queries only on keys and not on column names, please
>> verify.
>>
>
> Incorrect. You can slice a row or rows (identified by a key) on a column
> name range (e.g., "a" through "m") or ask for specific columns in a row or
> rows (e.g., please give me the "first_name," "last_name" and
> "hashed_password" fields from my Users column family where the key equals
> "mmalone").
>
> See the get_range_slices() method in the thrift service.
>
> Mike
>
>
>>
>>
>>
>> On Tue, May 11, 2010 at 11:06 AM, Mike Malone <m...@simplegeo.com> wrote:
>> >
>> >
>> > On Mon, May 10, 2010 at 9:00 PM, Shuge Lee <shuge....@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
>> >
>>
>
>
