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Discover how to efficiently count the results of your graph queries in ArangoDB. Great for beginners and intermediate users!
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This video is based on the question https://stackoverflow.com/q/63330373/ asked by the user 'Mustanish Altamash' ( https://stackoverflow.com/u/4147528/ ) and on the answer https://stackoverflow.com/a/63354323/ provided by the user 'darkheir' ( https://stackoverflow.com/u/1280608/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Count Results in Graph Traversal Using ArangoDB

As you dive into the world of databases, particularly with ArangoDB, you might find yourself confronted with questions on how to efficiently retrieve data. One such question came from a learner who wanted to know how to count results while performing graph traversal. Let’s break down this problem and provide a clear solution!

Understanding the Problem

During a guide on ArangoDB, the instructor utilized a dataset on flights and airports to demonstrate named and anonymous graph queries. A specific query was run to fetch a list of airports, which filtered airports in San Francisco that are tagged as VIP. Here’s a brief look at the original query:

[[See Video to Reveal this Text or Code Snippet]]

While this query provides a list of airports, the learner wanted to know how to count the possible results instead of simply fetching them.

Solution: Using the COUNT Function

The best approach to count the number of results generated by a query in ArangoDB is to encapsulate your original query within the COUNT function. This will allow you to get the total number of items without retrieving them all. Here’s how to modify the original query to incorporate counting:

Step-by-Step Solution

Start with the Original Query: Begin with the understanding of what your original query does.

Use the COUNT Function: Wrap the original query within the COUNT function for counting purposes.

Return a Placeholder: Instead of returning the actual results, return a placeholder value (like 1) for counting purposes.

Revised Query Example

Below is how your modified query should look:

[[See Video to Reveal this Text or Code Snippet]]

Explanation of the Modified Query

RETURN COUNT(...): This portion tells ArangoDB that you want to count the number of results that meet the criteria set in the enclosed query.

The inner query: Remains the same, allowing you to filter airports based on city and VIP status and traverse the graph to find connections.

RETURN 1: This is critical in the count; it acts as a placeholder to indicate each row that meets your conditions is worth one count.

Conclusion

By modifying your original query to include the COUNT function, you can efficiently gather insights about your data without overloading the system with unnecessary result sets. This approach not only streamlines your data handling but also enhances performance when working with larger datasets.

If you’re just starting with ArangoDB, remember that practice and experimentation with queries will help solidify your understanding. Happy querying!