A column family is a NoSQL object that contains columns of related data. It is a tuple (pair) that consists of a key-value pair, where the key is mapped to a value that is a set of columns. In analogy with relational databases, a column family is as a "table".
Questions tagged [column-family]
65 questions
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cassandra copy data from one columnfamily to another columnfamily from two different keyspaces
I am a newbie to cassandra. is there a way to copy data from one column family from a key space to another keyspace?
We have an application, that generates new keyspaces of same column families. We are thinking to merge all them into one keyspace…
Divakar
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cassandra: inconsistent column families
Taken from the example in http://www.ibm.com/developerworks/library/os-apache-cassandra/. Suppose we are concerning with two entities: books and tags. A book has multiple tags, so the relationship between them is 1:M.
According to the article, we…
user3839198
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Periodically receive "InvalidQueryException: unconfigured columnfamily documents"
We have an app that is basically polling periodically for changes every 1 minute, using Datastax c* driver 2.0.4 (also tried 2.1.0-beta1).
We create a Session at app startup, specifying the keyspace, e.g.
Session session =…
Tyson Norris
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understanding the code for inserting column family in Cassandra keyspace?
I am reading Cassandra- The definitive guide by E.Hewitt. I am in the fourth chapter where the author describes the code for sample Hotel application. The image from the book is given here for reference.
Here is the method for inserting rowkeys in…
brain storm
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How to Create a Column family in a Selected Cluster in HBase
In cassandra hector API allow to create table on a selected cluster as follows. I want to do the same thing using HBase, can someone please help me out?
This is how it can done using Cassandra :
public void createColumnFamily(Cluster cluster,…
Chamika Kasun
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3 answers
Does Cassandra read the whole row when limiting the number of requested results?
I am using cassandra 2.0.6. and have this table:
CREATE TABLE t (
id text,
idx bigint,
data bigint,
PRIMARY KEY (id, idx)
)
So say I got these rows:
id / idx / data
x 1 data1
x 2 data2
x 3 data3
.... goes on…
kostas.kougios
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NoSQL (cassandra) data model for my project
I need to have your opinion on my design of data model for my project. My project is real-time recommendation system. There are some collections of recommendation algorithms. it means something like this:
collection1 {
algorithm1, algorithm5,…
Jan Bouchner
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No data relationships in big table databases?
If the relationships between the data are as important as the data
itself (such as distance or path calculations), then don't use a
column family/big table database.
(Quoted from article Big data woes: Which database should I use? by Andrew…
Dominykas Mostauskis
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How do I get all the keys that are stored in the Cassandra 2.0.1 column family with scala using hector?
I have to enter some values with a key(suppose key1="1_100"), but before inserting the values i want to check that is key("1_100") is already inserted or not.I know it will replace the previous one, if exists. i only want to enter values if key is…
user2822316
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Truncate/Delete all the columns except one from the Cassandra
I have a column family like this -
create column family TEST
with key_validation_class = 'UTF8Type'
and comparator = 'UTF8Type'
and default_validation_class = 'UTF8Type'
and column_metadata = [ {column_name : 'date', validation_class :…
AKIWEB
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Cassandra column family for different data types
Below is the data which I need to represent in my Cassandra Column Family.
rowKey e1_name e1_schemaname e1_last_modified_date
123 (ByteArray value) abc (some string) …
arsenal
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Group three columns value into one colum in Cassandra?
Below is the data which I need to represent in my Cassandra Column Family.
rowKey e1_name e1_schemaname e1_last_modified_date
123 (ByteArray value) abc (some string) …
arsenal
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0
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3 answers
Composite Column Values in Cassandra?
Can we have a composite values in each columns in Cassandra Column Family?
user-id column1-name
123 (Column1-Value Column1-SchemaName Column1-LastModifiedDate)
userId is the rowKey here. And same thing will be for other columns as…
arsenal
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InvalidRequestException while inserting into Composite Columns using Astyanax
I am tyring to insert into Composite Column in Cassandra column family using Astyanax client. Each column will be a composite column meaning its value will be made of three values as shown in my ComplexType class. Below is my column family in…
arsenal
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RuntimeException: Unknown comparator 'CompositeType'
I need to create CompositeColumns in a Cassandra ColumnFamily.
Each column value will store the something like this-
user-id column1
123 (Column1-Value Column1-SchemaName LastModifiedDate)
same with column2 as well and other columns as…
AKIWEB
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