Re: yet a couple more questions on composite columns
On Sat, Feb 4, 2012 at 8:54 PM, Yiming Sun yiming@gmail.com wrote:
Interesting idea, Jim. Is there a reason you don't you use
metadata:{accountId} instead? For performance reasons?
No, because the column comparator is defined as
CompositeType(DateType, AsciiType), and all column names must conform
to that.
Jim
On Sat, Feb 4, 2012 at 6:24 PM, Jim Ancona j...@anconafamily.com wrote:
I've used special values which still comply with the Composite
schema for the metadata columns, e.g. a column of
1970-01-01:{accountId} for a metadata column where the Composite is
DateType:UTF8Type.
Jim
On Sat, Feb 4, 2012 at 2:13 PM, Yiming Sun yiming@gmail.com wrote:
Thanks Andrey and Chris. It sounds like we don't necessarily have to
use
composite columns. From what I understand about dynamic CF, each row
may
have completely different data from other rows; but in our case, the
data
in each row is similar to other rows; my concern was more about the
homogeneity of the data between columns.
In our original supercolumn-based schema, one special supercolumn is
called
metadata which contains a number of subcolumns to hold metadata
describing
each collection (e.g. number of documents, etc.), then the rest of the
supercolumns in the same row are all IDs of documents belong to the
collection, and for each document supercolumn, the subcolumns contain
the
document content as well as metadata on individual document (e.g.
checksum
of each document).
To move away from the supercolumn schema, I could either create two CFs,
one
to hold metadata, the other document content; or I could create just one
CF
mixing metadata and doc content in the same row, and using composite
column
names to identify if the particular column is metadata or a document. I
am
just wondering if you have any inputs on the pros and cons of each
schema.
-- Y.
On Fri, Feb 3, 2012 at 10:27 PM, Chris Gerken
chrisger...@mindspring.com
wrote:
On 4 February 2012 06:21, Yiming Sun yiming@gmail.com wrote:
I cannot have one composite column name with 3 components while
another
with 4 components?
Just put 4 components and left last empty (if it is same type)?!
Another question I have is how flexible composite columns actually
are.
If my data model has a CF containing US zip codes with the following
composite columns:
{OH:Spring Field} : 45503
{OH:Columbus} : 43085
{FL:Spring Field} : 32401
{FL:Key West} : 33040
I know I can ask cassandra to give me the zip codes of all cities in
OH. But can I ask it to give me the zip codes of all cities named
Spring
Field using this model? Thanks.
No. You set first composite component at first.
I'd use a dynamic CF:
row key = state abbreviation
column name = city name
column value = zip code (or a complex object, one of whose properties
is
zip code)
you can iterate over the columns in a single row to get a state's city
names and their zip code and you can do a get_range_slices on all keys
for
the columns starting and ending on the city name to find out the zip
codes
for a cities with the given name.
I think
- Chris
Re: yet a couple more questions on composite columns
Thanks for the clarification, Jim. I didn't know the first comparator was
defined as DateType. Yeah, in that case, the beginning of the epoch is the
only choice.
-- Y.
On Mon, Feb 6, 2012 at 11:35 AM, Jim Ancona j...@anconafamily.com wrote:
On Sat, Feb 4, 2012 at 8:54 PM, Yiming Sun yiming@gmail.com wrote:
Interesting idea, Jim. Is there a reason you don't you use
metadata:{accountId} instead? For performance reasons?
No, because the column comparator is defined as
CompositeType(DateType, AsciiType), and all column names must conform
to that.
Jim
On Sat, Feb 4, 2012 at 6:24 PM, Jim Ancona j...@anconafamily.com wrote:
I've used special values which still comply with the Composite
schema for the metadata columns, e.g. a column of
1970-01-01:{accountId} for a metadata column where the Composite is
DateType:UTF8Type.
Jim
On Sat, Feb 4, 2012 at 2:13 PM, Yiming Sun yiming@gmail.com
wrote:
Thanks Andrey and Chris. It sounds like we don't necessarily have to
use
composite columns. From what I understand about dynamic CF, each row
may
have completely different data from other rows; but in our case, the
data
in each row is similar to other rows; my concern was more about the
homogeneity of the data between columns.
In our original supercolumn-based schema, one special supercolumn is
called
metadata which contains a number of subcolumns to hold metadata
describing
each collection (e.g. number of documents, etc.), then the rest of the
supercolumns in the same row are all IDs of documents belong to the
collection, and for each document supercolumn, the subcolumns contain
the
document content as well as metadata on individual document (e.g.
checksum
of each document).
To move away from the supercolumn schema, I could either create two
CFs,
one
to hold metadata, the other document content; or I could create just
one
CF
mixing metadata and doc content in the same row, and using composite
column
names to identify if the particular column is metadata or a document.
I
am
just wondering if you have any inputs on the pros and cons of each
schema.
-- Y.
On Fri, Feb 3, 2012 at 10:27 PM, Chris Gerken
chrisger...@mindspring.com
wrote:
On 4 February 2012 06:21, Yiming Sun yiming@gmail.com wrote:
I cannot have one composite column name with 3 components while
another
with 4 components?
Just put 4 components and left last empty (if it is same type)?!
Another question I have is how flexible composite columns actually
are.
If my data model has a CF containing US zip codes with the
following
composite columns:
{OH:Spring Field} : 45503
{OH:Columbus} : 43085
{FL:Spring Field} : 32401
{FL:Key West} : 33040
I know I can ask cassandra to give me the zip codes of all cities
in
OH. But can I ask it to give me the zip codes of all cities named
Spring
Field using this model? Thanks.
No. You set first composite component at first.
I'd use a dynamic CF:
row key = state abbreviation
column name = city name
column value = zip code (or a complex object, one of whose properties
is
zip code)
you can iterate over the columns in a single row to get a state's
city
names and their zip code and you can do a get_range_slices on all
keys
for
the columns starting and ending on the city name to find out the zip
codes
for a cities with the given name.
I think
- Chris
Re: yet a couple more questions on composite columns
Yiming, I am using 2 CF's. Performance wise this should not be an issue. I
use it for small files data store. My 2 CF's are:
FilesMeta
FilesData
2012/2/5 Yiming Sun yiming@gmail.com
Interesting idea, Jim. Is there a reason you don't you use
metadata:{accountId} instead? For performance reasons?
On Sat, Feb 4, 2012 at 6:24 PM, Jim Ancona j...@anconafamily.com wrote:
I've used special values which still comply with the Composite
schema for the metadata columns, e.g. a column of
1970-01-01:{accountId} for a metadata column where the Composite is
DateType:UTF8Type.
Jim
On Sat, Feb 4, 2012 at 2:13 PM, Yiming Sun yiming@gmail.com wrote:
Thanks Andrey and Chris. It sounds like we don't necessarily have to
use
composite columns. From what I understand about dynamic CF, each row
may
have completely different data from other rows; but in our case, the
data
in each row is similar to other rows; my concern was more about the
homogeneity of the data between columns.
In our original supercolumn-based schema, one special supercolumn is
called
metadata which contains a number of subcolumns to hold metadata
describing
each collection (e.g. number of documents, etc.), then the rest of the
supercolumns in the same row are all IDs of documents belong to the
collection, and for each document supercolumn, the subcolumns contain
the
document content as well as metadata on individual document (e.g.
checksum
of each document).
To move away from the supercolumn schema, I could either create two
CFs, one
to hold metadata, the other document content; or I could create just
one CF
mixing metadata and doc content in the same row, and using composite
column
names to identify if the particular column is metadata or a document.
I am
just wondering if you have any inputs on the pros and cons of each
schema.
-- Y.
On Fri, Feb 3, 2012 at 10:27 PM, Chris Gerken
chrisger...@mindspring.com
wrote:
On 4 February 2012 06:21, Yiming Sun yiming@gmail.com wrote:
I cannot have one composite column name with 3 components while
another
with 4 components?
Just put 4 components and left last empty (if it is same type)?!
Another question I have is how flexible composite columns actually
are.
If my data model has a CF containing US zip codes with the following
composite columns:
{OH:Spring Field} : 45503
{OH:Columbus} : 43085
{FL:Spring Field} : 32401
{FL:Key West} : 33040
I know I can ask cassandra to give me the zip codes of all cities in
OH. But can I ask it to give me the zip codes of all cities named
Spring
Field using this model? Thanks.
No. You set first composite component at first.
I'd use a dynamic CF:
row key = state abbreviation
column name = city name
column value = zip code (or a complex object, one of whose properties
is
zip code)
you can iterate over the columns in a single row to get a state's city
names and their zip code and you can do a get_range_slices on all keys
for
the columns starting and ending on the city name to find out the zip
codes
for a cities with the given name.
I think
- Chris
Re: yet a couple more questions on composite columns
Thanks R.V.!! We are also dealing with many small files, so this sounds
really promising.
-- Y.
On Sun, Feb 5, 2012 at 9:59 AM, R. Verlangen ro...@us2.nl wrote:
Yiming, I am using 2 CF's. Performance wise this should not be an issue. I
use it for small files data store. My 2 CF's are:
FilesMeta
FilesData
2012/2/5 Yiming Sun yiming@gmail.com
Interesting idea, Jim. Is there a reason you don't you use
metadata:{accountId} instead? For performance reasons?
On Sat, Feb 4, 2012 at 6:24 PM, Jim Ancona j...@anconafamily.com wrote:
I've used special values which still comply with the Composite
schema for the metadata columns, e.g. a column of
1970-01-01:{accountId} for a metadata column where the Composite is
DateType:UTF8Type.
Jim
On Sat, Feb 4, 2012 at 2:13 PM, Yiming Sun yiming@gmail.com wrote:
Thanks Andrey and Chris. It sounds like we don't necessarily have to
use
composite columns. From what I understand about dynamic CF, each row
may
have completely different data from other rows; but in our case, the
data
in each row is similar to other rows; my concern was more about the
homogeneity of the data between columns.
In our original supercolumn-based schema, one special supercolumn is
called
metadata which contains a number of subcolumns to hold metadata
describing
each collection (e.g. number of documents, etc.), then the rest of the
supercolumns in the same row are all IDs of documents belong to the
collection, and for each document supercolumn, the subcolumns contain
the
document content as well as metadata on individual document (e.g.
checksum
of each document).
To move away from the supercolumn schema, I could either create two
CFs, one
to hold metadata, the other document content; or I could create just
one CF
mixing metadata and doc content in the same row, and using composite
column
names to identify if the particular column is metadata or a document.
I am
just wondering if you have any inputs on the pros and cons of each
schema.
-- Y.
On Fri, Feb 3, 2012 at 10:27 PM, Chris Gerken
chrisger...@mindspring.com
wrote:
On 4 February 2012 06:21, Yiming Sun yiming@gmail.com wrote:
I cannot have one composite column name with 3 components while
another
with 4 components?
Just put 4 components and left last empty (if it is same type)?!
Another question I have is how flexible composite columns actually
are.
If my data model has a CF containing US zip codes with the following
composite columns:
{OH:Spring Field} : 45503
{OH:Columbus} : 43085
{FL:Spring Field} : 32401
{FL:Key West} : 33040
I know I can ask cassandra to give me the zip codes of all cities in
OH. But can I ask it to give me the zip codes of all cities named
Spring
Field using this model? Thanks.
No. You set first composite component at first.
I'd use a dynamic CF:
row key = state abbreviation
column name = city name
column value = zip code (or a complex object, one of whose properties
is
zip code)
you can iterate over the columns in a single row to get a state's city
names and their zip code and you can do a get_range_slices on all
keys for
the columns starting and ending on the city name to find out the zip
codes
for a cities with the given name.
I think
- Chris
Re: yet a couple more questions on composite columns
Thanks Andrey and Chris. It sounds like we don't necessarily have to use
composite columns. From what I understand about dynamic CF, each row may
have completely different data from other rows; but in our case, the data
in each row is similar to other rows; my concern was more about the
homogeneity of the data between columns.
In our original supercolumn-based schema, one special supercolumn is called
metadata which contains a number of subcolumns to hold metadata
describing each collection (e.g. number of documents, etc.), then the rest
of the supercolumns in the same row are all IDs of documents belong to the
collection, and for each document supercolumn, the subcolumns contain the
document content as well as metadata on individual document (e.g. checksum
of each document).
To move away from the supercolumn schema, I could either create two CFs,
one to hold metadata, the other document content; or I could create just
one CF mixing metadata and doc content in the same row, and using composite
column names to identify if the particular column is metadata or a
document. I am just wondering if you have any inputs on the pros and cons
of each schema.
-- Y.
On Fri, Feb 3, 2012 at 10:27 PM, Chris Gerken chrisger...@mindspring.comwrote:
On 4 February 2012 06:21, Yiming Sun yiming@gmail.com wrote:
I cannot have one composite column name with 3 components while another
with 4 components?
Just put 4 components and left last empty (if it is same type)?!
Another question I have is how flexible composite columns actually are.
If my data model has a CF containing US zip codes with the following
composite columns:
{OH:Spring Field} : 45503
{OH:Columbus} : 43085
{FL:Spring Field} : 32401
{FL:Key West} : 33040
I know I can ask cassandra to give me the zip codes of all cities in
OH. But can I ask it to give me the zip codes of all cities named Spring
Field using this model? Thanks.
No. You set first composite component at first.
I'd use a dynamic CF:
row key = state abbreviation
column name = city name
column value = zip code (or a complex object, one of whose properties is
zip code)
you can iterate over the columns in a single row to get a state's city
names and their zip code and you can do a get_range_slices on all keys for
the columns starting and ending on the city name to find out the zip codes
for a cities with the given name.
I think
- Chris
Re: yet a couple more questions on composite columns
I also made something like this a while ago. I decided to go for the
2-rows-solution: by doing that you don't have the need for super columns.
Cassandra is really good at reading, so this should not be an issue.
Cheers!
2012/2/4 Yiming Sun yiming@gmail.com
Thanks Andrey and Chris. It sounds like we don't necessarily have to use
composite columns. From what I understand about dynamic CF, each row may
have completely different data from other rows; but in our case, the data
in each row is similar to other rows; my concern was more about the
homogeneity of the data between columns.
In our original supercolumn-based schema, one special supercolumn is
called metadata which contains a number of subcolumns to hold metadata
describing each collection (e.g. number of documents, etc.), then the rest
of the supercolumns in the same row are all IDs of documents belong to the
collection, and for each document supercolumn, the subcolumns contain the
document content as well as metadata on individual document (e.g. checksum
of each document).
To move away from the supercolumn schema, I could either create two CFs,
one to hold metadata, the other document content; or I could create just
one CF mixing metadata and doc content in the same row, and using composite
column names to identify if the particular column is metadata or a
document. I am just wondering if you have any inputs on the pros and cons
of each schema.
-- Y.
On Fri, Feb 3, 2012 at 10:27 PM, Chris Gerken
chrisger...@mindspring.comwrote:
On 4 February 2012 06:21, Yiming Sun yiming@gmail.com wrote:
I cannot have one composite column name with 3 components while another
with 4 components?
Just put 4 components and left last empty (if it is same type)?!
Another question I have is how flexible composite columns actually are.
If my data model has a CF containing US zip codes with the following
composite columns:
{OH:Spring Field} : 45503
{OH:Columbus} : 43085
{FL:Spring Field} : 32401
{FL:Key West} : 33040
I know I can ask cassandra to give me the zip codes of all cities in
OH. But can I ask it to give me the zip codes of all cities named Spring
Field using this model? Thanks.
No. You set first composite component at first.
I'd use a dynamic CF:
row key = state abbreviation
column name = city name
column value = zip code (or a complex object, one of whose properties is
zip code)
you can iterate over the columns in a single row to get a state's city
names and their zip code and you can do a get_range_slices on all keys for
the columns starting and ending on the city name to find out the zip codes
for a cities with the given name.
I think
- Chris
Re: yet a couple more questions on composite columns
Interesting idea, R.V. But what did you do with the row keys?
On Sat, Feb 4, 2012 at 2:29 PM, R. Verlangen ro...@us2.nl wrote:
I also made something like this a while ago. I decided to go for the
2-rows-solution: by doing that you don't have the need for super columns.
Cassandra is really good at reading, so this should not be an issue.
Cheers!
2012/2/4 Yiming Sun yiming@gmail.com
Thanks Andrey and Chris. It sounds like we don't necessarily have to use
composite columns. From what I understand about dynamic CF, each row may
have completely different data from other rows; but in our case, the data
in each row is similar to other rows; my concern was more about the
homogeneity of the data between columns.
In our original supercolumn-based schema, one special supercolumn is
called metadata which contains a number of subcolumns to hold metadata
describing each collection (e.g. number of documents, etc.), then the rest
of the supercolumns in the same row are all IDs of documents belong to the
collection, and for each document supercolumn, the subcolumns contain the
document content as well as metadata on individual document (e.g. checksum
of each document).
To move away from the supercolumn schema, I could either create two CFs,
one to hold metadata, the other document content; or I could create just
one CF mixing metadata and doc content in the same row, and using composite
column names to identify if the particular column is metadata or a
document. I am just wondering if you have any inputs on the pros and cons
of each schema.
-- Y.
On Fri, Feb 3, 2012 at 10:27 PM, Chris Gerken chrisger...@mindspring.com
wrote:
On 4 February 2012 06:21, Yiming Sun yiming@gmail.com wrote:
I cannot have one composite column name with 3 components while another
with 4 components?
Just put 4 components and left last empty (if it is same type)?!
Another question I have is how flexible composite columns actually are.
If my data model has a CF containing US zip codes with the following
composite columns:
{OH:Spring Field} : 45503
{OH:Columbus} : 43085
{FL:Spring Field} : 32401
{FL:Key West} : 33040
I know I can ask cassandra to give me the zip codes of all cities in
OH. But can I ask it to give me the zip codes of all cities named Spring
Field using this model? Thanks.
No. You set first composite component at first.
I'd use a dynamic CF:
row key = state abbreviation
column name = city name
column value = zip code (or a complex object, one of whose properties is
zip code)
you can iterate over the columns in a single row to get a state's city
names and their zip code and you can do a get_range_slices on all keys for
the columns starting and ending on the city name to find out the zip codes
for a cities with the given name.
I think
- Chris
Re: yet a couple more questions on composite columns
I just kept both row keys the same. This was very trivial for fetching them
both. When you have A, you can fetch B, and vice versa.
2012/2/4 Yiming Sun yiming@gmail.com
Interesting idea, R.V. But what did you do with the row keys?
On Sat, Feb 4, 2012 at 2:29 PM, R. Verlangen ro...@us2.nl wrote:
I also made something like this a while ago. I decided to go for the
2-rows-solution: by doing that you don't have the need for super columns.
Cassandra is really good at reading, so this should not be an issue.
Cheers!
2012/2/4 Yiming Sun yiming@gmail.com
Thanks Andrey and Chris. It sounds like we don't necessarily have to
use composite columns. From what I understand about dynamic CF, each row
may have completely different data from other rows; but in our case, the
data in each row is similar to other rows; my concern was more about the
homogeneity of the data between columns.
In our original supercolumn-based schema, one special supercolumn is
called metadata which contains a number of subcolumns to hold metadata
describing each collection (e.g. number of documents, etc.), then the rest
of the supercolumns in the same row are all IDs of documents belong to the
collection, and for each document supercolumn, the subcolumns contain the
document content as well as metadata on individual document (e.g. checksum
of each document).
To move away from the supercolumn schema, I could either create two CFs,
one to hold metadata, the other document content; or I could create just
one CF mixing metadata and doc content in the same row, and using composite
column names to identify if the particular column is metadata or a
document. I am just wondering if you have any inputs on the pros and cons
of each schema.
-- Y.
On Fri, Feb 3, 2012 at 10:27 PM, Chris Gerken
chrisger...@mindspring.com wrote:
On 4 February 2012 06:21, Yiming Sun yiming@gmail.com wrote:
I cannot have one composite column name with 3 components while
another with 4 components?
Just put 4 components and left last empty (if it is same type)?!
Another question I have is how flexible composite columns actually are.
If my data model has a CF containing US zip codes with the following
composite columns:
{OH:Spring Field} : 45503
{OH:Columbus} : 43085
{FL:Spring Field} : 32401
{FL:Key West} : 33040
I know I can ask cassandra to give me the zip codes of all cities in
OH. But can I ask it to give me the zip codes of all cities named
Spring
Field using this model? Thanks.
No. You set first composite component at first.
I'd use a dynamic CF:
row key = state abbreviation
column name = city name
column value = zip code (or a complex object, one of whose properties
is zip code)
you can iterate over the columns in a single row to get a state's city
names and their zip code and you can do a get_range_slices on all keys for
the columns starting and ending on the city name to find out the zip codes
for a cities with the given name.
I think
- Chris
Re: yet a couple more questions on composite columns
I've used special values which still comply with the Composite
schema for the metadata columns, e.g. a column of
1970-01-01:{accountId} for a metadata column where the Composite is
DateType:UTF8Type.
Jim
On Sat, Feb 4, 2012 at 2:13 PM, Yiming Sun yiming@gmail.com wrote:
Thanks Andrey and Chris. It sounds like we don't necessarily have to use
composite columns. From what I understand about dynamic CF, each row may
have completely different data from other rows; but in our case, the data
in each row is similar to other rows; my concern was more about the
homogeneity of the data between columns.
In our original supercolumn-based schema, one special supercolumn is called
metadata which contains a number of subcolumns to hold metadata describing
each collection (e.g. number of documents, etc.), then the rest of the
supercolumns in the same row are all IDs of documents belong to the
collection, and for each document supercolumn, the subcolumns contain the
document content as well as metadata on individual document (e.g. checksum
of each document).
To move away from the supercolumn schema, I could either create two CFs, one
to hold metadata, the other document content; or I could create just one CF
mixing metadata and doc content in the same row, and using composite column
names to identify if the particular column is metadata or a document. I am
just wondering if you have any inputs on the pros and cons of each schema.
-- Y.
On Fri, Feb 3, 2012 at 10:27 PM, Chris Gerken chrisger...@mindspring.com
wrote:
On 4 February 2012 06:21, Yiming Sun yiming@gmail.com wrote:
I cannot have one composite column name with 3 components while another
with 4 components?
Just put 4 components and left last empty (if it is same type)?!
Another question I have is how flexible composite columns actually are.
If my data model has a CF containing US zip codes with the following
composite columns:
{OH:Spring Field} : 45503
{OH:Columbus} : 43085
{FL:Spring Field} : 32401
{FL:Key West} : 33040
I know I can ask cassandra to give me the zip codes of all cities in
OH. But can I ask it to give me the zip codes of all cities named Spring
Field using this model? Thanks.
No. You set first composite component at first.
I'd use a dynamic CF:
row key = state abbreviation
column name = city name
column value = zip code (or a complex object, one of whose properties is
zip code)
you can iterate over the columns in a single row to get a state's city
names and their zip code and you can do a get_range_slices on all keys for
the columns starting and ending on the city name to find out the zip codes
for a cities with the given name.
I think
- Chris
Re: yet a couple more questions on composite columns
R.V., I am a little confused. I was under the impression that you cannot
have two rows with the same key - unless you were referring to two
different CFs?
On Sat, Feb 4, 2012 at 6:11 PM, R. Verlangen ro...@us2.nl wrote:
I just kept both row keys the same. This was very trivial for fetching
them both. When you have A, you can fetch B, and vice versa.
2012/2/4 Yiming Sun yiming@gmail.com
Interesting idea, R.V. But what did you do with the row keys?
On Sat, Feb 4, 2012 at 2:29 PM, R. Verlangen ro...@us2.nl wrote:
I also made something like this a while ago. I decided to go for the
2-rows-solution: by doing that you don't have the need for super columns.
Cassandra is really good at reading, so this should not be an issue.
Cheers!
2012/2/4 Yiming Sun yiming@gmail.com
Thanks Andrey and Chris. It sounds like we don't necessarily have to
use composite columns. From what I understand about dynamic CF, each row
may have completely different data from other rows; but in our case, the
data in each row is similar to other rows; my concern was more about the
homogeneity of the data between columns.
In our original supercolumn-based schema, one special supercolumn is
called metadata which contains a number of subcolumns to hold metadata
describing each collection (e.g. number of documents, etc.), then the rest
of the supercolumns in the same row are all IDs of documents belong to the
collection, and for each document supercolumn, the subcolumns contain the
document content as well as metadata on individual document (e.g. checksum
of each document).
To move away from the supercolumn schema, I could either create two
CFs, one to hold metadata, the other document content; or I could create
just one CF mixing metadata and doc content in the same row, and using
composite column names to identify if the particular column is metadata or
a document. I am just wondering if you have any inputs on the pros and
cons of each schema.
-- Y.
On Fri, Feb 3, 2012 at 10:27 PM, Chris Gerken
chrisger...@mindspring.com wrote:
On 4 February 2012 06:21, Yiming Sun yiming@gmail.com wrote:
I cannot have one composite column name with 3 components while
another with 4 components?
Just put 4 components and left last empty (if it is same type)?!
Another question I have is how flexible composite columns actually
are. If my data model has a CF containing US zip codes with the
following
composite columns:
{OH:Spring Field} : 45503
{OH:Columbus} : 43085
{FL:Spring Field} : 32401
{FL:Key West} : 33040
I know I can ask cassandra to give me the zip codes of all cities in
OH. But can I ask it to give me the zip codes of all cities named
Spring
Field using this model? Thanks.
No. You set first composite component at first.
I'd use a dynamic CF:
row key = state abbreviation
column name = city name
column value = zip code (or a complex object, one of whose properties
is zip code)
you can iterate over the columns in a single row to get a state's city
names and their zip code and you can do a get_range_slices on all keys for
the columns starting and ending on the city name to find out the zip codes
for a cities with the given name.
I think
- Chris
Re: yet a couple more questions on composite columns
Interesting idea, Jim. Is there a reason you don't you use
metadata:{accountId} instead? For performance reasons?
On Sat, Feb 4, 2012 at 6:24 PM, Jim Ancona j...@anconafamily.com wrote:
I've used special values which still comply with the Composite
schema for the metadata columns, e.g. a column of
1970-01-01:{accountId} for a metadata column where the Composite is
DateType:UTF8Type.
Jim
On Sat, Feb 4, 2012 at 2:13 PM, Yiming Sun yiming@gmail.com wrote:
Thanks Andrey and Chris. It sounds like we don't necessarily have to use
composite columns. From what I understand about dynamic CF, each row may
have completely different data from other rows; but in our case, the
data
in each row is similar to other rows; my concern was more about the
homogeneity of the data between columns.
In our original supercolumn-based schema, one special supercolumn is
called
metadata which contains a number of subcolumns to hold metadata
describing
each collection (e.g. number of documents, etc.), then the rest of the
supercolumns in the same row are all IDs of documents belong to the
collection, and for each document supercolumn, the subcolumns contain the
document content as well as metadata on individual document (e.g.
checksum
of each document).
To move away from the supercolumn schema, I could either create two CFs,
one
to hold metadata, the other document content; or I could create just one
CF
mixing metadata and doc content in the same row, and using composite
column
names to identify if the particular column is metadata or a document. I
am
just wondering if you have any inputs on the pros and cons of each
schema.
-- Y.
On Fri, Feb 3, 2012 at 10:27 PM, Chris Gerken
chrisger...@mindspring.com
wrote:
On 4 February 2012 06:21, Yiming Sun yiming@gmail.com wrote:
I cannot have one composite column name with 3 components while another
with 4 components?
Just put 4 components and left last empty (if it is same type)?!
Another question I have is how flexible composite columns actually are.
If my data model has a CF containing US zip codes with the following
composite columns:
{OH:Spring Field} : 45503
{OH:Columbus} : 43085
{FL:Spring Field} : 32401
{FL:Key West} : 33040
I know I can ask cassandra to give me the zip codes of all cities in
OH. But can I ask it to give me the zip codes of all cities named
Spring
Field using this model? Thanks.
No. You set first composite component at first.
I'd use a dynamic CF:
row key = state abbreviation
column name = city name
column value = zip code (or a complex object, one of whose properties is
zip code)
you can iterate over the columns in a single row to get a state's city
names and their zip code and you can do a get_range_slices on all keys
for
the columns starting and ending on the city name to find out the zip
codes
for a cities with the given name.
I think
- Chris
Re: yet a couple more questions on composite columns
On 4 February 2012 06:21, Yiming Sun yiming@gmail.com wrote:
I cannot have one composite column name with 3 components while another
with 4 components?
Just put 4 components and left last empty (if it is same type)?!
Another question I have is how flexible composite columns actually are. If
my data model has a CF containing US zip codes with the following composite
columns:
{OH:Spring Field} : 45503
{OH:Columbus} : 43085
{FL:Spring Field} : 32401
{FL:Key West} : 33040
I know I can ask cassandra to give me the zip codes of all cities in OH.
But can I ask it to give me the zip codes of all cities named Spring
Field using this model? Thanks.
No. You set first composite component at first.
Re: yet a couple more questions on composite columns
On 4 February 2012 06:21, Yiming Sun yiming@gmail.com wrote:
I cannot have one composite column name with 3 components while another with
4 components?
Just put 4 components and left last empty (if it is same type)?!
Another question I have is how flexible composite columns actually are. If
my data model has a CF containing US zip codes with the following composite
columns:
{OH:Spring Field} : 45503
{OH:Columbus} : 43085
{FL:Spring Field} : 32401
{FL:Key West} : 33040
I know I can ask cassandra to give me the zip codes of all cities in OH.
But can I ask it to give me the zip codes of all cities named Spring Field
using this model? Thanks.
No. You set first composite component at first.
I'd use a dynamic CF:
row key = state abbreviation
column name = city name
column value = zip code (or a complex object, one of whose properties is zip
code)
you can iterate over the columns in a single row to get a state's city names
and their zip code and you can do a get_range_slices on all keys for the
columns starting and ending on the city name to find out the zip codes for a
cities with the given name.
I think
- Chris
