![]() This however will all the documents for the associated event (may be many?) so the two-query solution may be more efficient. Ģ) the alternative is to do everything is a single query and return just the first and last documents from it: LET results = ( If there are no matching documents for the specified _id_event value, the queries will return null each. Just one document is returned from each query, and only that document is returned per query. the very first log entry, and the most recent log entry: [ġ) the first one is to execute two queries and return just the top/bottom document from each: RETURN [Īs you can see, one query is using sort order DESC and the other is using sort order ASC. I want a query that will return an array with only the first and last items, i.e. ![]() Here's an example: FOR event IN EventTran I’m trying to work out a query to return an array of only the first and last (by timestamp) EventTran documents for a specified id_event. ArangoDB Cloud Service The ArangoGraph Insights Platform is the simplest way to run ArangoDB. ArangoDB runs on-prem, in the cloud anywhere. Native graphs, an integrated search engine, and JSON support, via a single query language. ![]() EventTran attributes include a timestamp, and a reference to the parent _id_event. ArangoDB is a scalable graph database system to drive value from connected data, faster. I have a transaction detail collection ( EventTran) that logs update details on its parent table ( Event). For object keys there is the possibility to create an index on dedicated keys, but obviously the keys need to be known in advance.Īll that said, you may still want to make sure that objects/arrays do no get excessively big, because otherwise performance and memory usage may degrade.I need help with an ArangoDB AQL query. The same is true when querying for arbitrary object keys. peeking into the middle of an array from an AQL query will normally not use any index.Apart from that it may also limit the number of object keys/array members internally. There are two possible solutions: 1) the first one is to execute two queries and return just the top/bottom document from each: RETURN (FOR event IN EventTran FILTER event.idevent 'Event/167697' SORT event.timestamp DESC LIMIT 1 RETURN event ) 0, (FOR event IN EventTran FILTER event.idevent 'Event/167697' SORT event.timestamp. The V8 JavaScript implementation that is used by ArangoDB should behave well for small and medium-sized objects/arrays, but it has its problems with huge values. when using ArangoDB's Foxx microservice framework, the documents need to be converted to plain JavaScript objects & arrays. when using huge documents from ArangoDB's JavaScript functionality, e.g.However, the performance of the full iteration of all object keys or all array values will grow linearly with the number of members. searching for specifying object keys inside documents normally uses a binary search, so its performance degrades logarithmically with the number of object keys. ![]() This will especially hurt with the RocksDB storage engine, as due to the level design of RocksDB each document revision may need to be shoved through the various levels of the LSM tree and thus needs to be copied/written several times. The performance of reading and writing individual documents obviously depends on the document size, so the bigger the documents are, the slower this will get and the more memory each individual document will consume during querying. ![]() the more array/object members you use in a document, the bigger the document will grow byte-wise.However, there are a few practical limits that you may want to consider: We'll cover the required configuration, basic CRUD operations, custom queries, and entities relations. It supports key-value, document, and graph data models with one database core and a unified query language: AQL (ArangoDB Query Language). There is no artificial limit in place for the number of array values or object keys in ArangoDB. ArangoDB is a free and open-source multi-model database system. ![]()
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