What is KijiSchema?

KijiSchema provides a simple Java API and command line interface for importing, managing, and retrieving data from HBase.

Key Features

  • Set up HBase layouts using user-friendly tools including a DDL
  • Implement HBase best practices in table management
  • Use evolving Avro schema management to serialize complex data
  • Perform both short-request and batch processing on data in HBase
  • Import data from HDFS into structured HBase tables

KijiSchema promotes the use of entity-centric data modeling, where all information about a given entity, including both dimensional and transaction data, is encoded within the same row. This approach is particularly valuable for user-based analytics such as targeting, recommendations, and personalization.

Using KijiSchema in Your Project

You will need to include KijiSchema as a dependency in your project. If you’re using Maven, this can be included as follows in your pom.xml in the <dependencies> block:

<dependency>
  <groupId>org.kiji.schema</groupId>
  <artifactId>kiji-schema</artifactId>
  <version>1.1.2</version>
  <scope>provided</scope>
</dependency>

<dependency>
  <groupId>org.kiji.platforms</groupId>
  <artifactId>kiji-cdh4-platform</artifactId>
  <version>1.1.0</version>
  <scope>provided</scope>
</dependency>

Because you typically launch Kiji applications by running bin/kiji jar /path/to/example.jar, you can list this as a provided dependency; the runtime environment will provide the implementation jars, so you do not need to bundle them in your application. If you intend to bundle your application (e.g., for deployment within a Tomcat container), you should list your scope as:

<scope>compile</scope>

This ensures that Kiji’s jars will be included in your assembled application.

You will need to compile against a specific version of Hadoop and HBase. The kiji-cdh4-platform dependency specifies which Hadoop platform you depend on; in this case, CDH4. See the kiji-platforms repository for more information.

You’ll probably need to configure your Maven settings.xml to locate these dependencies. See Getting started with Maven for more details.