Скачать или смотреть Understanding psql’s \dt PATTERN: How to Effectively List Triggers in PostgreSQL

Discover how to use `psql`’s `\dt PATTERN` command to effectively locate triggers in PostgreSQL, especially when searching for specific keywords like `new`!
---
This video is based on the question https://stackoverflow.com/q/62360173/ asked by the user 'Eugen Konkov' ( https://stackoverflow.com/u/4632019/ ) and on the answer https://stackoverflow.com/a/62360243/ provided by the user 'GMB' ( https://stackoverflow.com/u/10676716/ ) 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: How psql's \dt PATTERN works?

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 psql’s \dt PATTERN: How to Effectively List Triggers in PostgreSQL

When working with PostgreSQL, you might find yourself needing to inspect your database objects, including triggers. But what happens when you can't find the triggers you believe are there? This is a common problem users face — wanting to search for specific keywords in trigger names using the psql command line interface, and struggling to grasp how the \dt PATTERN command functions. This post aims to clarify this command and provide you with useful tips on searching for triggers efficiently.

The Challenge: Searching for Triggers

Imagine you are trying to identify specific triggers containing the word new. You attempt to use the command:

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

Yet, the output shows 0 rows. Confused, you might wonder if the PATTERN parameter works like a regex, especially since the keyword isn't being recognized. So, what is PATTERN, and how can you effectively find those elusive triggers?

Understanding \dFt and the PATTERN Parameter

The \dFt command in psql is designed to list all functions, including triggers. The PATTERN parameter allows you to do a more targeted search by filtering results based on specified patterns.

Key Points about PATTERN:

Not a Regex: While you might think of it as a regex, PATTERN works more like a simple wildcard search.

Placement of Wildcards: Using * allows you to represent any series of characters.

Effective Usage of the Command

Finding Triggers with Specific Keywords: To search for triggers containing the word new, you should adjust your command to include wildcards around the keyword. Here’s the correct command to do this:

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

This command effectively searches for any trigger that contains the substring new, regardless of what comes before or after it.

Searching Across All Schemas: If you want to broaden your search and include all schemas in your database, you can further modify your command:

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

By adding *.*, you're asking PostgreSQL to search within all schemas for triggers containing new in their names.

Conclusion

Understanding how to effectively use the \dt PATTERN command can significantly enhance your ability to manage and inspect triggers within PostgreSQL. By implementing the wildcards correctly, you can quickly locate any functions or triggers that might have previously seemed hidden.

Quick Tips:

Always remember to surround your keyword with * to expand your search.

If you are unsure about the exact naming conventions in your database, consider using broader patterns.

Now you can confidently navigate your database and retrieve the information you need about your triggers!