Implementing ArangoDB aggregation queries using Java

ArangoDB is an open source Multi-model database that supports multiple aggregate query operations. Using Java to connect and operate ArangoDB can be achieved by adding corresponding Maven dependencies using the ArangoDB Java driver. 1. Connect to ArangoDB database: Firstly, it is necessary to add the dependencies of ArangoDB Java driver to the pom.xml file of the project: <dependencies> <dependency> <groupId>com.arangodb</groupId> <artifactId>arangodb-java-driver</artifactId> <version>6.17.0</version> </dependency> </dependencies> Next, use the following code to connect to the ArangoDB database: import com.arangodb.ArangoDB; import com.arangodb.ArangoDatabase; ArangoDB arangoDB = new ArangoDB.Builder().build(); ArangoDatabase db = arangoDB.db("<database-name>"); 2. Execute aggregation query: Here are some common ArangoDB aggregation queries and their Java implementation examples: -Calculate the total number of documents in the collection: import com.arangodb.ArangoCursor; import com.arangodb.entity.BaseDocument; import com.arangodb.model.AqlQueryOptions; String aql = "RETURN LENGTH(<collection-name>)"; ArangoCursor<BaseDocument> cursor = db.query(aql, new AqlQueryOptions(), BaseDocument.class); -Calculate the number of documents in the set that meet the conditions: String aql = "RETURN LENGTH(FOR doc IN <collection-name> FILTER doc.<field-name> == <value> RETURN doc)"; ArangoCursor<BaseDocument> cursor = db.query(aql, new AqlQueryOptions(), BaseDocument.class); -Obtain the average value of all documents in the collection: String aql = "RETURN AVG(FOR doc IN <collection-name> RETURN doc.<field-name>)"; ArangoCursor<BaseDocument> cursor = db.query(aql, new AqlQueryOptions(), BaseDocument.class); -Obtain the maximum value of a field in the collection: String aql = "RETURN MAX(FOR doc IN <collection-name> RETURN doc.<field-name>)"; ArangoCursor<BaseDocument> cursor = db.query(aql, new AqlQueryOptions(), BaseDocument.class); -Sort the documents in the collection by a certain field and return the first n documents: String aql = "FOR doc IN <collection-name> SORT doc.<field-name> DESC LIMIT <n> RETURN doc"; ArangoCursor<BaseDocument> cursor = db.query(aql, new AqlQueryOptions(), BaseDocument.class); These examples demonstrate how to use ArangoDB Java driver to perform various aggregation query operations. You can customize AQL query statements according to specific needs and use corresponding Java classes to process the results.