CollectionOperations interface provides 'ensureHashIndex' method to create a hash index for the collection if it does not already exist. Query by example queries use this index.
Signature
IndexEntity ensureHashIndex(Iterable<String> fields, HashIndexOptions options) throws DataAccessException;
‘HashIndexOptions’ is used to provide additional options which are used while creating the index. Below table summarizes possible options associated with HashIndexOptions.
|
Option |
Data type |
Description |
|
inBackground |
Boolean |
create the the index in the background |
|
name |
String |
name of the index |
|
fields |
Iterable<String> |
list of attribute paths like a, a.b, a.b.c etc., |
|
type |
IndexType |
IndexType is an enum and can be one of a. primary, b. hash, c. skiplist, d. persistent, e. geo, f. geo1, g. geo2, h. fulltext, i. edge, j. ttl |
|
unique |
Boolean |
if true, then create a unique index |
|
sparse |
Boolean |
if true, then create a sparse index |
|
deduplicate |
Boolean |
if false, the deduplication of array values is turned off. |
Example
HashIndexOptions hashIndexOptions = new HashIndexOptions();
hashIndexOptions.name("nameIndex");
empsCollection.ensureHashIndex(Arrays.asList("firstName", "lastName"), hashIndexOptions);
Find the below working application.
Step 1: Create new maven project ‘collection-operations-create-hash-index’.
Step 2: Update pom.xml with maven dependencies.
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.sample.app</groupId>
<artifactId>collection-operations-create-hash-index</artifactId>
<version>1</version>
<!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-parent -->
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.4.5</version>
</parent>
<dependencies>
<dependency>
<groupId>com.arangodb</groupId>
<artifactId>arangodb-spring-boot-starter</artifactId>
<version>2.3.3.RELEASE</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
Step 3: Define entity class.
Employee.java
package com.sample.app.entity;
import com.arangodb.springframework.annotation.ArangoId;
import com.arangodb.springframework.annotation.Document;
import org.springframework.data.annotation.Id;
@Document("employees")
public class Employee {
@Id // db document field: _key
private String key;
@ArangoId // db document field: _id
private String arangoId;
private Integer id;
private String firstName;
private String lastName;
private Integer age;
public Employee(Integer id, String firstName, String lastName, Integer age) {
super();
this.id = id;
this.firstName = firstName;
this.lastName = lastName;
this.age = age;
}
public Employee() {
}
public String getKey() {
return key;
}
public void setKey(String key) {
this.key = key;
}
public String getArangoId() {
return arangoId;
}
public void setArangoId(String arangoId) {
this.arangoId = arangoId;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
@Override
public String toString() {
return "Employee [key=" + key + ", arangoId=" + arangoId + ", id=" + id + ", firstName=" + firstName
+ ", lastName=" + lastName + ", age=" + age + "]";
}
}
Step 4: Define arango configuration class.
ArangoConfig.java
package com.sample.app.config;
import org.springframework.context.annotation.Configuration;
import com.arangodb.ArangoDB;
import com.arangodb.springframework.annotation.EnableArangoRepositories;
import com.arangodb.springframework.config.ArangoConfiguration;
@Configuration
@EnableArangoRepositories(basePackages = { "com.sample.app" })
public class ArangoConfig implements ArangoConfiguration {
@Override
public ArangoDB.Builder arango() {
return new ArangoDB.Builder().host("localhost", 8529).user("root").password("tiger");
}
@Override
public String database() {
return "abc_org";
}
}
Step 5: Define main application class.
App.java
package com.sample.app;
import java.util.Arrays;
import java.util.Collection;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import com.arangodb.entity.IndexEntity;
import com.arangodb.model.HashIndexOptions;
import com.arangodb.springframework.core.ArangoOperations;
import com.arangodb.springframework.core.CollectionOperations;
import com.sample.app.entity.Employee;
@SpringBootApplication
public class App {
@Autowired
private ArangoOperations arangoTemplate;
public static void main(String args[]) {
SpringApplication.run(App.class, args);
}
@Bean
public CommandLineRunner demo() {
return (args) -> {
Employee emp1 = new Employee(1, "Krishna", "Gurram", 33);
Employee emp2 = new Employee(2, "Lahari", "G", 20);
Employee emp3 = new Employee(3, "Thulasi", "G", 19);
arangoTemplate.insert(Arrays.asList(emp1, emp2, emp3), Employee.class);
Iterable<Employee> empsIterable = arangoTemplate.findAll(Employee.class);
System.out.println("Documents in employees collection");
for (Employee emp : empsIterable) {
System.out.println(emp);
}
CollectionOperations empsCollection = arangoTemplate.collection(Employee.class);
HashIndexOptions hashIndexOptions = new HashIndexOptions();
hashIndexOptions.name("nameIndex");
empsCollection.ensureHashIndex(Arrays.asList("firstName", "lastName"), hashIndexOptions);
Collection<IndexEntity> indexesCollection = empsCollection.getIndexes();
System.out.println("\nTotal indexes : " + indexesCollection.size());
for (IndexEntity indexEntity : indexesCollection) {
System.out.println("\nindex details");
System.out.println("name : " + indexEntity.getName());
System.out.println("Index created on fields : " + indexEntity.getFields());
}
System.out.println("\nDropping the collection");
empsCollection.drop();
};
}
}
Total project structure looks like below.
Run App.java, you will see below messages in console.
Documents in employees collection Employee [key=51679, arangoId=employees/51679, id=1, firstName=Krishna, lastName=Gurram, age=33] Employee [key=51680, arangoId=employees/51680, id=2, firstName=Lahari, lastName=G, age=20] Employee [key=51681, arangoId=employees/51681, id=3, firstName=Thulasi, lastName=G, age=19] Total indexes : 2 index details name : primary Index created on fields : [_key] index details name : nameIndex Index created on fields : [firstName, lastName] Dropping the collection
You can download complete working application from below link.
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