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Mongodb json query5/26/2023 ![]() ![]() I’m going to use Exploratory’s UI to demonstrate, but all the examples can be used with any other tools including Mongo Shell. Today, I’m going to walk you through the basics of MongoDB query with a bunch of examples so that you can start writing the queries to work with MongoDB data effectively. Though you don’t need to be an expert of MongoDB query, knowing just the enough level of MongoDB query will make your entire data wrangling and analysis flow much more smooth and more efficient. So I’d usually recommend a hybrid approach, which is to use MongoDB Query at a minimal level to extract just the enough data, not the whole, from the database and import it into Exploratory, then do the nitty gritty world of data wrangling there for faster and easier data exploration. However, as you would imagine, that might not be always efficient or even practical sometimes due to the time it takes to download the data and the memory size limit of your PC. or simply with UI tools like Exploratory (UI for R). Well, of course, you can always import the whole data from MongoDB to R’s in-memory for much easier data exploration with packages like ‘mongolite’, ‘dplyr’, ‘tidyr’, etc. Now having said that, querying MongoDB data is not as straightforward as dplyr or even SQL due to the MongoDB Query’s JSON and JavaScript flavor that makes the queries hard to read and a bit more complicated. We store most of the data we have in MongoDB because it’s so easy to store and manage in a way that allows us to keep changing the scheme, which is super critical and essential for startups like us who are constantly experimenting by changing things. Object or array cannot be found in the specified JSON path.Īs expected, strict mode results in an error message explaining the error.We at Exploratory use MongoDB quite a lot. ![]() Result: Msg 13624, Level 16, State 2, Line 1 SELECT JSON_QUERY('', 'strict $.Name') AS 'Result' Here’s what happens when the path expression contains an error while in lax mode. Here’s an example to demonstrate the difference between these two modes. In strict mode, the function raises an error if the path expression contains an error. For example, if you request the value $.name, and the JSON text doesn’t contain a name key, the function returns null, but does not raise an error.
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