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Posted to user@hbase.apache.org by y_...@tsmc.com on 2009/06/26 11:14:13 UTC
Try to get qualifier collection
Hi there,
I have a table "Table1" with one Family and 10 qualifier.
Any ways that I can get these qualifier's name in Table1,
then I can loop qualifier collection to fetch each qualifier's value.
Thank you
Fleming
====================================================================================
HTable table = new HTable(config, "Table1");
Get g = new Get(Bytes.toBytes("Key1"));
Result r = table.get(g);
byte [] value1 = r.getValue(Bytes.toBytes("Family"),
Bytes.toBytes("qualifier1"));
String valueStr1 = Bytes.toString(value1);
byte [] value2 = r.getValue(Bytes.toBytes("Family"),
Bytes.toBytes("qualifier2"));
String valueStr2 = Bytes.toString(value2);
.
.
.
byte [] value10 = r.getValue(Bytes.toBytes("Family"),
Bytes.toBytes("qualifier10"));
String valueStr10 = Bytes.toString(value10);
---------------------------------------------------------------------------
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This email communication (and any attachments) is proprietary information
for the sole use of its
intended recipient. Any unauthorized review, use or distribution by anyone
other than the intended
recipient is strictly prohibited. If you are not the intended recipient,
please notify the sender by
replying to this email, and then delete this email and any copies of it
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Re: Try to get qualifier collection
Posted by Jonathan Gray <jl...@streamy.com>.
The Map<byte[],Cell> is a mapping from "column" to its value(s).
A "column" is made up of the "family" and "qualifier". Notated in 0.19
as: family:qualifier
So if you iterator the RowResult:
for(Map.Entry<byte[],Cell> entry : rowResult.entrySet()) {
byte [] column = entry.getKey();
// column is of form: family:qualifier
}
0.20 splits these up in two fields so that you don't have to split/merge
all over your code. I used my own utility methods to handle the joint
family:qualifier but I think there are also methods in Bytes utility class.
Ishaaq Chandy wrote:
> Thanks for the quick responses guys.
>
> Yes, I did look at RowResult but its not very obvious what its supposed to
> do when dealing with a column family that consists of multiple qualifiers.
> Does each column family get a single key or does each qualifier get a single
> key in the entry set?
>
> I'm sorry, I guess I could run a test and check what it does but I am
> physically away from my machine which has HBase installed so I can't verify
> this - so I resorted to the documentation which didn't seem too clear to me.
>
> Thanks again,
> Ishaaq
>
>
>
> stack-3 wrote:
>> On Mon, Jul 6, 2009 at 6:39 PM, Ishaaq Chandy <is...@gmail.com> wrote:
>>
>>> Hmm, I have a similar requirement. However, when looking at the API I
>>> cannot
>>> see these classes: Get and Result. Are these 0.20.0 classes? If so, what
>>> would be the equivalent for 0.19.3?
>>
>>
>> Yes. These are 0.20.0 classes.
>>
>> In 0.19.3, use RowResult. Iterate entrySet:
>> http://hadoop.apache.org/hbase/docs/r0.19.3/api/org/apache/hadoop/hbase/io/RowResult.html#entrySet().
>> Its keyed by column.
>>
>> St.Ack
>>
>>
>> Thanks,
>>> Ishaaq
>>>
>>>
>>> Jonathan Gray-2 wrote:
>>>> Fleming,
>>>>
>>>> Of course there is!
>>>>
>>>> Look at some of the different methods in Result that return various
>>> Maps
>>>> in different format. For your example, you might do:
>>>>
>>>> =======
>>>>
>>>> HTable table = new HTable("Table1");
>>>> Get g = new Get(Bytes.toBytes("Key1"));
>>>> Result r = table.get(g);
>>>>
>>>> // Get a Map<qualifier,value> for Family
>>>>
>>>> Map<byte[],byte[]> family = r.getFamilyMap(Bytes.toBytes("Family"));
>>>>
>>>> // You can get a value knowing the qualifier
>>>>
>>>> byte [] value1 = family.get(Bytes.toBytes("qualifier1"));
>>>>
>>>> // Or you can just iterate all the qualifiers and values
>>>>
>>>> for(Map.Entry<byte[],byte[]> entry : family.entrySet()) {
>>>> byte [] qualifier = entry.getKey();
>>>> byte [] value = entry.getValue();
>>>> }
>>>>
>>>> =======
>>>>
>>>> All the maps that are returned by Result are NavigableMaps, so they are
>>>> sorted and allow a number of operations on them.
>>>>
>>>> Hope that helps.
>>>>
>>>> JG
>>>>
>>>> y_823910@tsmc.com wrote:
>>>>> Hi there,
>>>>>
>>>>> I have a table "Table1" with one Family and 10 qualifier.
>>>>> Any ways that I can get these qualifier's name in Table1,
>>>>> then I can loop qualifier collection to fetch each qualifier's value.
>>>>> Thank you
>>>>>
>>>>> Fleming
>>>>>
>>>>>
>>> ====================================================================================
>>>>> HTable table = new HTable(config, "Table1");
>>>>> Get g = new Get(Bytes.toBytes("Key1"));
>>>>> Result r = table.get(g);
>>>>> byte [] value1 = r.getValue(Bytes.toBytes("Family"),
>>>>> Bytes.toBytes("qualifier1"));
>>>>> String valueStr1 = Bytes.toString(value1);
>>>>> byte [] value2 = r.getValue(Bytes.toBytes("Family"),
>>>>> Bytes.toBytes("qualifier2"));
>>>>> String valueStr2 = Bytes.toString(value2);
>>>>> .
>>>>> .
>>>>> .
>>>>>
>>>>> byte [] value10 = r.getValue(Bytes.toBytes("Family"),
>>>>> Bytes.toBytes("qualifier10"));
>>>>> String valueStr10 = Bytes.toString(value10);
>>>>>
>>>>>
>>> ---------------------------------------------------------------------------
>>>>> TSMC PROPERTY
>>>>> This email communication (and any attachments) is proprietary
>>>>> information
>>>>> for the sole use of its
>>>>> intended recipient. Any unauthorized review, use or distribution by
>>>>> anyone
>>>>> other than the intended
>>>>> recipient is strictly prohibited. If you are not the intended
>>>>> recipient,
>>>>> please notify the sender by
>>>>> replying to this email, and then delete this email and any copies of
>>> it
>>>>> immediately. Thank you.
>>>>>
>>>>>
>>> ---------------------------------------------------------------------------
>>>>>
>>>>>
>>>>
>>> --
>>> View this message in context:
>>> http://www.nabble.com/Try-to-get-qualifier-collection-tp24217280p24365806.html
>>> Sent from the HBase User mailing list archive at Nabble.com.
>>>
>>>
>>
>
Re: Try to get qualifier collection
Posted by Ishaaq Chandy <is...@gmail.com>.
Thanks for the quick responses guys.
Yes, I did look at RowResult but its not very obvious what its supposed to
do when dealing with a column family that consists of multiple qualifiers.
Does each column family get a single key or does each qualifier get a single
key in the entry set?
I'm sorry, I guess I could run a test and check what it does but I am
physically away from my machine which has HBase installed so I can't verify
this - so I resorted to the documentation which didn't seem too clear to me.
Thanks again,
Ishaaq
stack-3 wrote:
>
> On Mon, Jul 6, 2009 at 6:39 PM, Ishaaq Chandy <is...@gmail.com> wrote:
>
>>
>> Hmm, I have a similar requirement. However, when looking at the API I
>> cannot
>> see these classes: Get and Result. Are these 0.20.0 classes? If so, what
>> would be the equivalent for 0.19.3?
>
>
>
> Yes. These are 0.20.0 classes.
>
> In 0.19.3, use RowResult. Iterate entrySet:
> http://hadoop.apache.org/hbase/docs/r0.19.3/api/org/apache/hadoop/hbase/io/RowResult.html#entrySet().
> Its keyed by column.
>
> St.Ack
>
>
> Thanks,
>> Ishaaq
>>
>>
>> Jonathan Gray-2 wrote:
>> >
>> > Fleming,
>> >
>> > Of course there is!
>> >
>> > Look at some of the different methods in Result that return various
>> Maps
>> > in different format. For your example, you might do:
>> >
>> > =======
>> >
>> > HTable table = new HTable("Table1");
>> > Get g = new Get(Bytes.toBytes("Key1"));
>> > Result r = table.get(g);
>> >
>> > // Get a Map<qualifier,value> for Family
>> >
>> > Map<byte[],byte[]> family = r.getFamilyMap(Bytes.toBytes("Family"));
>> >
>> > // You can get a value knowing the qualifier
>> >
>> > byte [] value1 = family.get(Bytes.toBytes("qualifier1"));
>> >
>> > // Or you can just iterate all the qualifiers and values
>> >
>> > for(Map.Entry<byte[],byte[]> entry : family.entrySet()) {
>> > byte [] qualifier = entry.getKey();
>> > byte [] value = entry.getValue();
>> > }
>> >
>> > =======
>> >
>> > All the maps that are returned by Result are NavigableMaps, so they are
>> > sorted and allow a number of operations on them.
>> >
>> > Hope that helps.
>> >
>> > JG
>> >
>> > y_823910@tsmc.com wrote:
>> >> Hi there,
>> >>
>> >> I have a table "Table1" with one Family and 10 qualifier.
>> >> Any ways that I can get these qualifier's name in Table1,
>> >> then I can loop qualifier collection to fetch each qualifier's value.
>> >> Thank you
>> >>
>> >> Fleming
>> >>
>> >>
>> ====================================================================================
>> >>
>> >> HTable table = new HTable(config, "Table1");
>> >> Get g = new Get(Bytes.toBytes("Key1"));
>> >> Result r = table.get(g);
>> >> byte [] value1 = r.getValue(Bytes.toBytes("Family"),
>> >> Bytes.toBytes("qualifier1"));
>> >> String valueStr1 = Bytes.toString(value1);
>> >> byte [] value2 = r.getValue(Bytes.toBytes("Family"),
>> >> Bytes.toBytes("qualifier2"));
>> >> String valueStr2 = Bytes.toString(value2);
>> >> .
>> >> .
>> >> .
>> >>
>> >> byte [] value10 = r.getValue(Bytes.toBytes("Family"),
>> >> Bytes.toBytes("qualifier10"));
>> >> String valueStr10 = Bytes.toString(value10);
>> >>
>> >>
>> ---------------------------------------------------------------------------
>> >> TSMC PROPERTY
>> >> This email communication (and any attachments) is proprietary
>> >> information
>> >> for the sole use of its
>> >> intended recipient. Any unauthorized review, use or distribution by
>> >> anyone
>> >> other than the intended
>> >> recipient is strictly prohibited. If you are not the intended
>> >> recipient,
>> >> please notify the sender by
>> >> replying to this email, and then delete this email and any copies of
>> it
>> >> immediately. Thank you.
>> >>
>> >>
>> ---------------------------------------------------------------------------
>> >>
>> >>
>> >>
>> >
>> >
>>
>> --
>> View this message in context:
>> http://www.nabble.com/Try-to-get-qualifier-collection-tp24217280p24365806.html
>> Sent from the HBase User mailing list archive at Nabble.com.
>>
>>
>
>
--
View this message in context: http://www.nabble.com/Try-to-get-qualifier-collection-tp24217280p24366338.html
Sent from the HBase User mailing list archive at Nabble.com.
Re: Try to get qualifier collection
Posted by stack <st...@duboce.net>.
On Mon, Jul 6, 2009 at 6:39 PM, Ishaaq Chandy <is...@gmail.com> wrote:
>
> Hmm, I have a similar requirement. However, when looking at the API I
> cannot
> see these classes: Get and Result. Are these 0.20.0 classes? If so, what
> would be the equivalent for 0.19.3?
Yes. These are 0.20.0 classes.
In 0.19.3, use RowResult. Iterate entrySet:
http://hadoop.apache.org/hbase/docs/r0.19.3/api/org/apache/hadoop/hbase/io/RowResult.html#entrySet().
Its keyed by column.
St.Ack
Thanks,
> Ishaaq
>
>
> Jonathan Gray-2 wrote:
> >
> > Fleming,
> >
> > Of course there is!
> >
> > Look at some of the different methods in Result that return various Maps
> > in different format. For your example, you might do:
> >
> > =======
> >
> > HTable table = new HTable("Table1");
> > Get g = new Get(Bytes.toBytes("Key1"));
> > Result r = table.get(g);
> >
> > // Get a Map<qualifier,value> for Family
> >
> > Map<byte[],byte[]> family = r.getFamilyMap(Bytes.toBytes("Family"));
> >
> > // You can get a value knowing the qualifier
> >
> > byte [] value1 = family.get(Bytes.toBytes("qualifier1"));
> >
> > // Or you can just iterate all the qualifiers and values
> >
> > for(Map.Entry<byte[],byte[]> entry : family.entrySet()) {
> > byte [] qualifier = entry.getKey();
> > byte [] value = entry.getValue();
> > }
> >
> > =======
> >
> > All the maps that are returned by Result are NavigableMaps, so they are
> > sorted and allow a number of operations on them.
> >
> > Hope that helps.
> >
> > JG
> >
> > y_823910@tsmc.com wrote:
> >> Hi there,
> >>
> >> I have a table "Table1" with one Family and 10 qualifier.
> >> Any ways that I can get these qualifier's name in Table1,
> >> then I can loop qualifier collection to fetch each qualifier's value.
> >> Thank you
> >>
> >> Fleming
> >>
> >>
> ====================================================================================
> >>
> >> HTable table = new HTable(config, "Table1");
> >> Get g = new Get(Bytes.toBytes("Key1"));
> >> Result r = table.get(g);
> >> byte [] value1 = r.getValue(Bytes.toBytes("Family"),
> >> Bytes.toBytes("qualifier1"));
> >> String valueStr1 = Bytes.toString(value1);
> >> byte [] value2 = r.getValue(Bytes.toBytes("Family"),
> >> Bytes.toBytes("qualifier2"));
> >> String valueStr2 = Bytes.toString(value2);
> >> .
> >> .
> >> .
> >>
> >> byte [] value10 = r.getValue(Bytes.toBytes("Family"),
> >> Bytes.toBytes("qualifier10"));
> >> String valueStr10 = Bytes.toString(value10);
> >>
> >>
> ---------------------------------------------------------------------------
> >> TSMC PROPERTY
> >> This email communication (and any attachments) is proprietary
> >> information
> >> for the sole use of its
> >> intended recipient. Any unauthorized review, use or distribution by
> >> anyone
> >> other than the intended
> >> recipient is strictly prohibited. If you are not the intended
> >> recipient,
> >> please notify the sender by
> >> replying to this email, and then delete this email and any copies of it
> >> immediately. Thank you.
> >>
> >>
> ---------------------------------------------------------------------------
> >>
> >>
> >>
> >
> >
>
> --
> View this message in context:
> http://www.nabble.com/Try-to-get-qualifier-collection-tp24217280p24365806.html
> Sent from the HBase User mailing list archive at Nabble.com.
>
>
Re: Try to get qualifier collection
Posted by Jonathan Gray <jl...@streamy.com>.
These are 0.20.0 classes.
The 0.19 API and earlier provided a very different view of the data.
Check out RowResult, which contained a Map<byte[],Cell>.
Ishaaq Chandy wrote:
> Hmm, I have a similar requirement. However, when looking at the API I cannot
> see these classes: Get and Result. Are these 0.20.0 classes? If so, what
> would be the equivalent for 0.19.3?
>
> Thanks,
> Ishaaq
>
>
> Jonathan Gray-2 wrote:
>> Fleming,
>>
>> Of course there is!
>>
>> Look at some of the different methods in Result that return various Maps
>> in different format. For your example, you might do:
>>
>> =======
>>
>> HTable table = new HTable("Table1");
>> Get g = new Get(Bytes.toBytes("Key1"));
>> Result r = table.get(g);
>>
>> // Get a Map<qualifier,value> for Family
>>
>> Map<byte[],byte[]> family = r.getFamilyMap(Bytes.toBytes("Family"));
>>
>> // You can get a value knowing the qualifier
>>
>> byte [] value1 = family.get(Bytes.toBytes("qualifier1"));
>>
>> // Or you can just iterate all the qualifiers and values
>>
>> for(Map.Entry<byte[],byte[]> entry : family.entrySet()) {
>> byte [] qualifier = entry.getKey();
>> byte [] value = entry.getValue();
>> }
>>
>> =======
>>
>> All the maps that are returned by Result are NavigableMaps, so they are
>> sorted and allow a number of operations on them.
>>
>> Hope that helps.
>>
>> JG
>>
>> y_823910@tsmc.com wrote:
>>> Hi there,
>>>
>>> I have a table "Table1" with one Family and 10 qualifier.
>>> Any ways that I can get these qualifier's name in Table1,
>>> then I can loop qualifier collection to fetch each qualifier's value.
>>> Thank you
>>>
>>> Fleming
>>>
>>> ====================================================================================
>>>
>>> HTable table = new HTable(config, "Table1");
>>> Get g = new Get(Bytes.toBytes("Key1"));
>>> Result r = table.get(g);
>>> byte [] value1 = r.getValue(Bytes.toBytes("Family"),
>>> Bytes.toBytes("qualifier1"));
>>> String valueStr1 = Bytes.toString(value1);
>>> byte [] value2 = r.getValue(Bytes.toBytes("Family"),
>>> Bytes.toBytes("qualifier2"));
>>> String valueStr2 = Bytes.toString(value2);
>>> .
>>> .
>>> .
>>>
>>> byte [] value10 = r.getValue(Bytes.toBytes("Family"),
>>> Bytes.toBytes("qualifier10"));
>>> String valueStr10 = Bytes.toString(value10);
>>>
>>> ---------------------------------------------------------------------------
>>> TSMC PROPERTY
>>> This email communication (and any attachments) is proprietary
>>> information
>>> for the sole use of its
>>> intended recipient. Any unauthorized review, use or distribution by
>>> anyone
>>> other than the intended
>>> recipient is strictly prohibited. If you are not the intended
>>> recipient,
>>> please notify the sender by
>>> replying to this email, and then delete this email and any copies of it
>>> immediately. Thank you.
>>>
>>> ---------------------------------------------------------------------------
>>>
>>>
>>>
>>
>
Re: Try to get qualifier collection
Posted by Ishaaq Chandy <is...@gmail.com>.
Hmm, I have a similar requirement. However, when looking at the API I cannot
see these classes: Get and Result. Are these 0.20.0 classes? If so, what
would be the equivalent for 0.19.3?
Thanks,
Ishaaq
Jonathan Gray-2 wrote:
>
> Fleming,
>
> Of course there is!
>
> Look at some of the different methods in Result that return various Maps
> in different format. For your example, you might do:
>
> =======
>
> HTable table = new HTable("Table1");
> Get g = new Get(Bytes.toBytes("Key1"));
> Result r = table.get(g);
>
> // Get a Map<qualifier,value> for Family
>
> Map<byte[],byte[]> family = r.getFamilyMap(Bytes.toBytes("Family"));
>
> // You can get a value knowing the qualifier
>
> byte [] value1 = family.get(Bytes.toBytes("qualifier1"));
>
> // Or you can just iterate all the qualifiers and values
>
> for(Map.Entry<byte[],byte[]> entry : family.entrySet()) {
> byte [] qualifier = entry.getKey();
> byte [] value = entry.getValue();
> }
>
> =======
>
> All the maps that are returned by Result are NavigableMaps, so they are
> sorted and allow a number of operations on them.
>
> Hope that helps.
>
> JG
>
> y_823910@tsmc.com wrote:
>> Hi there,
>>
>> I have a table "Table1" with one Family and 10 qualifier.
>> Any ways that I can get these qualifier's name in Table1,
>> then I can loop qualifier collection to fetch each qualifier's value.
>> Thank you
>>
>> Fleming
>>
>> ====================================================================================
>>
>> HTable table = new HTable(config, "Table1");
>> Get g = new Get(Bytes.toBytes("Key1"));
>> Result r = table.get(g);
>> byte [] value1 = r.getValue(Bytes.toBytes("Family"),
>> Bytes.toBytes("qualifier1"));
>> String valueStr1 = Bytes.toString(value1);
>> byte [] value2 = r.getValue(Bytes.toBytes("Family"),
>> Bytes.toBytes("qualifier2"));
>> String valueStr2 = Bytes.toString(value2);
>> .
>> .
>> .
>>
>> byte [] value10 = r.getValue(Bytes.toBytes("Family"),
>> Bytes.toBytes("qualifier10"));
>> String valueStr10 = Bytes.toString(value10);
>>
>> ---------------------------------------------------------------------------
>> TSMC PROPERTY
>> This email communication (and any attachments) is proprietary
>> information
>> for the sole use of its
>> intended recipient. Any unauthorized review, use or distribution by
>> anyone
>> other than the intended
>> recipient is strictly prohibited. If you are not the intended
>> recipient,
>> please notify the sender by
>> replying to this email, and then delete this email and any copies of it
>> immediately. Thank you.
>>
>> ---------------------------------------------------------------------------
>>
>>
>>
>
>
--
View this message in context: http://www.nabble.com/Try-to-get-qualifier-collection-tp24217280p24365806.html
Sent from the HBase User mailing list archive at Nabble.com.
Re: Try to get qualifier collection
Posted by Jonathan Gray <jl...@streamy.com>.
Fleming,
Of course there is!
Look at some of the different methods in Result that return various Maps
in different format. For your example, you might do:
=======
HTable table = new HTable("Table1");
Get g = new Get(Bytes.toBytes("Key1"));
Result r = table.get(g);
// Get a Map<qualifier,value> for Family
Map<byte[],byte[]> family = r.getFamilyMap(Bytes.toBytes("Family"));
// You can get a value knowing the qualifier
byte [] value1 = family.get(Bytes.toBytes("qualifier1"));
// Or you can just iterate all the qualifiers and values
for(Map.Entry<byte[],byte[]> entry : family.entrySet()) {
byte [] qualifier = entry.getKey();
byte [] value = entry.getValue();
}
=======
All the maps that are returned by Result are NavigableMaps, so they are
sorted and allow a number of operations on them.
Hope that helps.
JG
y_823910@tsmc.com wrote:
> Hi there,
>
> I have a table "Table1" with one Family and 10 qualifier.
> Any ways that I can get these qualifier's name in Table1,
> then I can loop qualifier collection to fetch each qualifier's value.
> Thank you
>
> Fleming
>
> ====================================================================================
>
> HTable table = new HTable(config, "Table1");
> Get g = new Get(Bytes.toBytes("Key1"));
> Result r = table.get(g);
> byte [] value1 = r.getValue(Bytes.toBytes("Family"),
> Bytes.toBytes("qualifier1"));
> String valueStr1 = Bytes.toString(value1);
> byte [] value2 = r.getValue(Bytes.toBytes("Family"),
> Bytes.toBytes("qualifier2"));
> String valueStr2 = Bytes.toString(value2);
> .
> .
> .
>
> byte [] value10 = r.getValue(Bytes.toBytes("Family"),
> Bytes.toBytes("qualifier10"));
> String valueStr10 = Bytes.toString(value10);
> ---------------------------------------------------------------------------
> TSMC PROPERTY
> This email communication (and any attachments) is proprietary information
> for the sole use of its
> intended recipient. Any unauthorized review, use or distribution by anyone
> other than the intended
> recipient is strictly prohibited. If you are not the intended recipient,
> please notify the sender by
> replying to this email, and then delete this email and any copies of it
> immediately. Thank you.
> ---------------------------------------------------------------------------
>
>
>