How to Use Dexie.js to Filter Records by ShipmentID in IndexedDB скачать в хорошем качестве

How to Use Dexie.js to Filter Records by ShipmentID in IndexedDB

Learn how to resolve the common issue of retrieving multiple records with `Dexie.js` by correctly filtering based on `shipmentid`. --- This video is based on the question https://stackoverflow.com/q/74773246/ asked by the user 'Badhusha' ( https://stackoverflow.com/u/8018614/ ) and on the answer https://stackoverflow.com/a/76216975/ provided by the user 'Omkar Singh' ( https://stackoverflow.com/u/7447805/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions. Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Dexiejs - Filtering returns single value Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l... The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license. If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com. --- Filter Records in IndexedDB with Dexie.js When working with client-side databases like IndexedDB, it’s important to correctly structure your queries to retrieve the data you need. A common scenario that developers encounter is filtering records based on a specific field. In this guide, we will explore a situation where a developer attempts to fetch all records with a particular shipmentid using Dexie.js, only to receive just one record instead. By the end of this article, you’ll learn how to resolve this issue and effectively retrieve multiple records. Understanding the Database Structure Let's first take a look at the database setup. The developer initializes the Dexie database as follows: [[See Video to Reveal this Text or Code Snippet]] Here, the database shipment-execution contains a table root with three fields: id (auto-incrementing primary key) shipmentid (a unique identifier for each shipment) stopid (a unique identifier for stops related to each shipment) Sample Data The current structure of the IndexedDB contains the following records: idshipmentidstopid16000001102600000120360000013046000002105600000220The goal is to fetch all records where shipmentid equals 6000001. However, when the following code is executed: [[See Video to Reveal this Text or Code Snippet]] The output only returns the first record: idshipmentidstopid1600000110Identifying the Issue The issue arises because of how the query is structured. The current usage of .where() may be causing the filter to misinterpret the criteria, particularly due to how shipmentid is being compared (as a string). This can lead to results that are not as expected. Correcting the Query To retrieve all matching records, the developer should modify the query using the equals() method, ensuring that it is accurately filtering based on the shipmentid. Here’s the corrected code: [[See Video to Reveal this Text or Code Snippet]] Points to Keep in Mind Data Type Consistency: Ensure that the type of shipmentid used in the comparison matches the data type stored in the database (string vs number). In this case, '6000001' should be a string if defined so in the database, or you might need to convert it to a number if that’s the expected type. Async Programming: Since operations with Dexie are asynchronous, wrapping your function in an async function helps manage the flow of data retrieval effectively. Conclusion By updating the query to use the equals() method correctly, you can successfully fetch all relevant records from your IndexedDB based on specific criteria. This adjustment is crucial for ensuring that your database queries perform as expected, especially when managing relationships between different pieces of data. With the knowledge acquired from this post, you will now be better equipped to handle similar challenges in your own projects. Don't forget to double-check data types and leverage async patterns when working with databases for optimal results.