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Hive is a database technology that can define databases and tables to analyze structured data. The theme for structured data analysis is to store the data in a tabular manner, and pass queries to analyze it. This chapter explains how to create Hive database. Hive contains a default database named default.
Create Database Statement
Create Database is a statement used to create a database in Hive. A database in Hive is a namespace or a collection of tables. The syntax for this statement is as follows:
CREATE DATABASE|SCHEMA [IF NOT EXISTS] <database name>
Here, IF NOT EXISTS is an optional clause, which notifies the user that a database with the same name already exists. We can use SCHEMA in place of DATABASE in this command. The following query is executed to create a database named userdb:
hive> CREATE DATABASE [IF NOT EXISTS] userdb;
or
hive> CREATE SCHEMA userdb;
The following query is used to verify a databases list:
hive> SHOW DATABASES; default userdb
JDBC Program
The JDBC program to create a database is given below.
import java.sql.SQLException; import java.sql.Connection; import java.sql.ResultSet; import java.sql.Statement; import java.sql.DriverManager; public class HiveCreateDb { private static String driverName = "org.apache.hadoop.hive.jdbc.HiveDriver"; public static void main(String[] args) throws SQLException { // Register driver and create driver instance Class.forName(driverName); // get connection Connection con = DriverManager.getConnection("jdbc:hive://localhost:10000/default", "", ""); Statement stmt = con.createStatement(); stmt.executeQuery("CREATE DATABASE userdb"); System.out.println(“Database userdb created successfully.”); con.close(); } }
Save the program in a file named HiveCreateDb.java. The following commands are used to compile and execute this program.
$ javac HiveCreateDb.java $ java HiveCreateDb
Output:
Database userdb created successfully.
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