In this Article, I will show How to work with Cassandra Bound Statement.
How this differ from Prepared Statement.
Few questions come to mind, while using Bound Statement are.
When to Use Bound Statement?
– If the provided statements that map to different tables? Yes
– The goal of the bound statement is to be able to execute a bunch
of different queries that follow some similar query structure,
But not the exact same query concurrently.
Tools Uses :
1) spring-data-cassandra-1.2.1.RELEASE
2) Apache-cassandra-2.1.6
3) eclipse version Luna 4.4.1.
4) Maven 3.3.3
5) JDK 1.6 or above
If you are completely new to Apache Cassandra,
please refer apache-cassandra-quick-start
Prerequisites :
1) Cassandra Server should be up and running.
2) key space should be created with name “devJavaSource”
Steps to be followed :
1) Create a maven project in eclipse.
2) Add cassandra-driver-core 2.1.6 jar file as dependency in pom.xml file.
3) Start Cassandra server.
4) Write a simple java program.
5) Demo
2) Add cassandra-driver-core 2.1.6 jar file as dependency in pom.xml file :
Cassandra java driver cassandra-driver-core 2.1.6 jar is required to run java program,
So add this as dependency in pom.xml file.
<dependency> <groupId>com.datastax.cassandra</groupId> <artifactId>cassandra-driver-core</artifactId> <version>2.1.6</version> </dependency>
3) Start Cassandra server :
Go to your home directory, where cassandra server is installed or extracted.
Command to start Casandra server is,
C:\apache-cassandra-2.1.6\bin> cassandra.bat -f
4) Write a simple java program :
Create a simple maven project and add Cassandra dependency.
Complete pom.xml file is Here,
pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.devjavasource.cassandra</groupId>
<artifactId>boundStatement</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>boundStatement</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.datastax.cassandra</groupId>
<artifactId>cassandra-driver-core</artifactId>
<version>2.1.6</version>
</dependency>
</dependencies>
</project>
Written two java files,
User.java – Is a simple Value Object, holds one user details.
User.java
package com.devjavasource.cassandra.boundStatement;
public class User {
private String id;
private String name;
private String address;
public User(String id, String address, String name){
this.id = id;
this.address = address;
this.name = name;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
}
Another java that doing cassandra insert and update the user details in User.
App.java
package com.devjavasource.cassandra.boundStatement;
import com.datastax.driver.core.BoundStatement;
import com.datastax.driver.core.Cluster;
import com.datastax.driver.core.PreparedStatement;
import com.datastax.driver.core.Session;
import com.datastax.driver.core.ResultSet;
import com.datastax.driver.core.Row;
public class App {
public static void main(String[] args) {
Cluster cluster = null;
Session session = null;
try {
// Connect to the cluster and keyspace "devjavasource"
final Cluster.Builder clusterBuilder = Cluster.builder()
.addContactPoint("127.0.0.1").withPort(9042)
.withCredentials("devjavasource", "devjavasource");
cluster = clusterBuilder.build();
session = cluster.connect("devjavasource");
// database operations insert
PreparedStatement insertStatement = session.prepare(INSERT_QUERY);
User user = new User("11104", "USA", "Stuart");
bindValuesToStatement(insertStatement, session, user);
getUsersAllDetails(session);
// database operations update
PreparedStatement updateStatement = session.prepare(UPDATE_QUERY);
user.setName("Stuart_Updated");
user.setAddress("USA_Updated");
bindValuesToStatement(updateStatement, session, user);
getUsersAllDetails(session);
// delete the inserted record
session.execute(" delete FROM users where id = 11104");
} catch (final Exception exp) {
exp.printStackTrace();
} finally {
// Close Cluster and Session objects
cluster.close();
session.close();
}
}
private static void bindValuesToStatement(
final PreparedStatement inPreparedStatement,
final Session inSession, final User inUser) {
BoundStatement boundStatement = new BoundStatement(inPreparedStatement);
boundStatement.enableTracing();
inSession.execute(boundStatement.bind(inUser.getAddress(),
inUser.getName(), Integer.parseInt(inUser.getId())));
}
private static void getUsersAllDetails(final Session inSession) {
// Use select to get the users table data
ResultSet results = inSession.execute("SELECT * FROM users");
for (Row row : results) {
System.out.format("%s %d %s\n", row.getString("name"),
row.getInt("id"), row.getString("address"));
}
}
final static String INSERT_QUERY = "INSERT INTO users (address, name, id ) VALUES (?, ?, ?)";
final static String UPDATE_QUERY = "UPDATE users set address = ?, name=? WHERE id= ?";
}
Run Maven project :
Select and Run As -> Java Application.
Out Put :
******* database operations insert ******** Stuart 11104 USA ******* database operations update ******** Stuart_Updated 11104 USA_Updated
You can download complete project, Here
*** Venkat – Happy learning ****