Скачать или смотреть How to Use FTS4 for Full-Text Search in SQLite with Two Columns

Learn how to implement Full-Text Search (FTS4) in SQLite for multiple columns, troubleshoot common issues, and optimize your queries with our step-by-step guide.
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This video is based on the question https://stackoverflow.com/q/71916771/ asked by the user 'Sebastián Ardila' ( https://stackoverflow.com/u/7216007/ ) and on the answer https://stackoverflow.com/a/71924005/ provided by the user 'bwt' ( https://stackoverflow.com/u/1283554/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Utilizing FTS4 for Full-Text Search in SQLite with Two Columns

When working with SQLite, one might often encounter the need to perform full-text searches across multiple columns in a table. If you have a table containing fields such as ldap and name, and you're looking to implement FTS4 for efficient searching, you may run into a few challenges. In this post, we'll address these challenges and guide you through the correct implementation of FTS4 with SQLite.

The Problem: Empty Search Results

A common issue arises when users attempt to create a virtual table for full-text searching and end up with empty results, despite having inserted relevant data. Consider this scenario:

You have created a virtual table with the following statement:

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Upon inserting a row with data:

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

And executing a search query such as:

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

Surprisingly, the result returns empty, which can be quite frustrating. Let's delve into the solution to ensure you can effectively search through your data.

The Solution: Modifying Your Trigger

The key to resolving the empty results lies in how you handle the insertion of data into the FTS4 virtual table. When using an external content table, it is crucial to provide a value for the docid, which should correspond to the rowid of the content table.

Step-by-Step Guide

Modify Your Trigger: Make sure your trigger correctly inserts data into the FTS table. Here’s the revised trigger to include the docid:

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Insert Data: Now, when you insert data, the docid will automatically reference the rowid of the content table, allowing FTS4 to function correctly:

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

Performing the Search: With the trigger set up to correctly record docid, you can now perform the full-text search reliably:

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

Expected Outcome

By implementing these changes, you should now receive the expected search results that contain the relevant row corresponding to the search term 'Bry'.

Conclusion

FTS4 in SQLite is a powerful tool for managing full-text searches across multiple columns. By ensuring that your triggers and insertions are set up correctly, you can avoid the frustrating issue of empty search results. Always remember to provide the correct docid to enhance your search capabilities.

Happy querying!