Solving the react-native-sqllite value not displayed Issue

Описание: Discover how to effectively retrieve and display data from SQLite in React Native using promises for improved functionality.
---
This video is based on the question https://stackoverflow.com/q/65824688/ asked by the user 'Shariq' ( https://stackoverflow.com/u/8520339/ ) and on the answer https://stackoverflow.com/a/65825429/ provided by the user 'Honey' ( https://stackoverflow.com/u/4215953/ ) 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: react-native-sqllite value not displayed

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.
---
Understanding the react-native-sqllite value not displayed Issue

If you're working with React Native and SQLite, you may encounter a frustrating problem where your data is not displayed outside of the database transaction block. This situation typically arises when you want to access the results of a database query after it has been executed asynchronously. In this guide, we will break down this issue and provide a clear, structured solution to help you display your data successfully.

The Problem

When querying the database, a common pattern involves using a transaction and executing SQL commands within that transaction. Here's a concise code snippet showcasing the problem:

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

In the code above, userDetails is displayed correctly within the tx.executeSql callback, but it remains empty when you try to access it outside of the db.transaction block. This is due to the asynchronous nature of the database operation. The SQL execution happens after the console log for userDetails runs, resulting in an empty array being logged.

The Solution

To resolve this issue, we need to ensure that we handle the asynchronous nature of the database calls. One way to do this is by leveraging JavaScript promises. By defining a promise, we can effectively wait for the results of the database query before proceeding.

Step 1: Define a Promise Function

First, we'll create a function called dbAction that returns a promise. Inside this promise, we will conduct our database transaction. Here's how it looks:

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

In this definition:

We initialize a new promise.

Once the SQL query is executed, we either resolve it with the retrieved details or handle errors through rejection.

Step 2: Retrieve Data Using async/await

Now that we have our promise-ready function, we can rewrite the getDetails function to use async/await, making it cleaner and more straightforward:

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

Key Points

Async/Await: The use of async lets us wait for the promise returned by dbAction. This ensures the results are available before we log them.

Error Handling: It's always a good practice to wrap the await call in a try/catch block to handle any potential errors gracefully.

Conclusion

By incorporating promises and the async/await syntax into your SQLite queries in React Native, you can effectively manage asynchronous behavior and access your data as expected. The method demonstrated here not only resolves the react-native-sqllite value not displayed issue but also enhances your application's reliability.

Now you can confidently retrieve and display data from your SQLite database without running into those frustrating undefined values! Happy coding!