Implementing OrientDB aggregation queries using Java
The use of Java to implement various aggregation queries in OrientDB can be achieved through the use of OrientDB's Java API and SQL statements. Here is a simple step to implement various data aggregation queries.
1. Add OrientDB Maven dependency
<dependency>
<groupId>com.orientechnologies</groupId>
<artifactId>orientdb-graphdb</artifactId>
<version>3.0.0</version>
</dependency>
2. Create OrientDB database connection
import com.orientechnologies.orient.core.db.ODatabaseSession;
import com.orientechnologies.orient.core.db.OrientDB;
OrientDB orientDB = new OrientDB("remote:localhost", OrientDBConfig.defaultConfig());
ODatabaseSession db = orientDB.open("database", "admin", "admin");
3. Execute aggregation queries
import com.orientechnologies.orient.core.db.document.ODatabaseDocument;
import com.orientechnologies.orient.core.sql.executor.OResult;
import com.orientechnologies.orient.core.sql.executor.OResultSet;
String sql = "SELECT COUNT(*) FROM Person";
OResultSet resultSet = db.query(sql);
long count = resultSet.next().getProperty("COUNT");
resultSet.close();
In the above code, we executed a simple count aggregation query using the SELECT COUNT (*) statement and stored the results in the variable count.
Here are several examples of other aggregated queries:
-Average Query
String sql = "SELECT AVG(age) FROM Person";
OResultSet resultSet = db.query(sql);
double averageAge = resultSet.next().getProperty("AVG");
resultSet.close();
-Sum query
String sql = "SELECT SUM(salary) FROM Employee";
OResultSet resultSet = db.query(sql);
double totalSalary = resultSet.next().getProperty("SUM");
resultSet.close();
-Maximum Query
String sql = "SELECT MAX(salary) FROM Employee";
OResultSet resultSet = db.query(sql);
double maxSalary = resultSet.next().getProperty("MAX");
resultSet.close();
-Minimum value query
String sql = "SELECT MIN(salary) FROM Employee";
OResultSet resultSet = db.query(sql);
double minSalary = resultSet.next().getProperty("MIN");
resultSet.close();
These examples demonstrate how to use Java to implement various aggregation queries for OrientDB. You can use different SQL statements as needed to execute various aggregation queries and use Java code to process the returned results.
