HBase Create Table - HBase

How to create a table in HBase?

Creating a Table using HBase Shell

Table can be created using create command by specifying the table name and the Column Family name. Syntax for creating a table in HBase shell is shown below.

create ‘<table name>’,’<column family>’

Example

Below is a sample schema of a table named emp which has two column families: “personal data” and “professional data”.

This table can be created in HBase shell as shown below.

hbase(main):002:0> create 'emp', 'personal data', 'professional data'

This will give you below output.

0 row(s) in 1.1300 seconds => Hbase::Table – emp

Verification

User can verify if the table is created using the list command as shown below. Here you can observe the created emp table.

hbase(main):002:0> list TABLE emp 2 row(s) in 0.0340 seconds

Creating a Table Using java API

A table in HBase can be created using createTable() method of HBaseAdmin class. This class belongs to org.apache.hadoop.hbase.client package. Below are the steps for creating a table in HBase using java API.

Step1: Instantiate HBaseAdmin

This class requires the Configuration object as a parameter, therefore initially instantiate the Configuration class and pass this instance to HBaseAdmin.

Configuration conf = HBaseConfiguration.create(); HBaseAdmin admin = new HBaseAdmin(conf);

Step2: Create TableDescriptor

HTableDescriptor is a class which belongs to the org.apache.hadoop.hbase class. This class is like a container of table names and column families. //creating table descriptor HTableDescriptor table = new HTableDescriptor(toBytes("Table name")); //creating column family descriptor HColumnDescriptor family = new HColumnDescriptor(toBytes("column family")); //adding coloumn family to HTable table.addFamily(family);

Step 3: Execute through Admin

Created table can be executed in Admin mode Using createTable() method of HBaseAdmin class.

admin.createTable(table);

Below is the complete program for creating a table via admin.

import java.io.IOException; import org.apache.hadoop.hbase.HBaseConfiguration; import org.apache.hadoop.hbase.HColumnDescriptor; import org.apache.hadoop.hbase.HTableDescriptor; import org.apache.hadoop.hbase.client.HBaseAdmin; import org.apache.hadoop.hbase.TableName; import org.apache.hadoop.conf.Configuration; public class CreateTable { public static void main(String[] args) throws IOException { // Instantiating configuration class Configuration con = HBaseConfiguration.create(); // Instantiating HbaseAdmin class HBaseAdmin admin = new HBaseAdmin(con); // Instantiating table descriptor class HTableDescriptor tableDescriptor = new HTableDescriptor(TableName.valueOf("emp")); // Adding column families to table descriptor tableDescriptor.addFamily(new HColumnDescriptor("personal")); tableDescriptor.addFamily(new HColumnDescriptor("professional")); // Execute the table through admin admin.createTable(tableDescriptor); System.out.println(" Table created "); } }

Compile and execute the above program as shown below.

$javac CreateTable.java $java CreateTable

Output:

Table created