Скачать или смотреть How to Set collate en_us.UTF-8 for Order By Queries in Sequelize

Learn how to properly use the `collate` setting in Sequelize to achieve case-insensitive sorting in PostgreSQL with ease.
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Working with Collation in Sequelize for PostgreSQL

When working with databases, sorting data in a case-insensitive manner can be crucial for maintaining usability. In PostgreSQL, you can achieve this by setting a specific collation like en_US.UTF-8. However, when using an ORM like Sequelize, implementing such database-specific features may not be straightforward. This post will guide you through the process of applying the en_us.UTF-8 collation in your order by queries using Sequelize.

Understanding the Problem

In PostgreSQL, a common method to perform case-insensitive ordering is by using the ORDER BY clause combined with the COLLATE keyword. A traditional SQL command might look like this:

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

This specifies that we want to convert the column to lower case using the en_US collation, thereby treating all records as lowercase for sorting purposes. However, when working in Sequelize, it's not immediately clear how to translate this SQL query into Sequelize syntax.

The Solution

Sequelize allows us to perform complex queries, but it often requires using functions like sequelize.fn for specific operations. To set the collate option correctly in an order by query in Sequelize, you should follow this structured approach:

Step-by-Step Implementation

Use sequelize.fn and sequelize.literal:
In Sequelize, you can use sequelize.fn to call SQL functions like convert_to and lower. You can use sequelize.literal to treat a string as raw SQL, making it easier to apply PostgreSQL-specific syntax such as COLLATE.

Construct the Query:
Here's how you should structure the order by clause in your Sequelize query:

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

Breakdown of the Code

sequelize.fn('convert_to', ...): This calls the PostgreSQL function convert_to, which helps convert the result into UTF8 format.

sequelize.fn('lower', sequelize.literal(...)): This applies the lower function to the column while using raw SQL to specify the collation.

sequelize.literal('column COLLATE "en_US"'): This allows you to directly input the SQL syntax needed for PostgreSQL's collation.

Important Notes

No Single Quotes Needed: When passing 'UTF8', it should be provided without single quotes in the sequelize.fn. Just pass the string directly: 'UTF8'.

Case Sensitivity: By using COLLATE "en_US", you're making sure that this ordering isn't affected by case, which enhances the user's experience when querying the database.

Conclusion

Setting up collation for ordering in Sequelize may initially seem complex, but understanding how to leverage PostgreSQL functions through Sequelize's simplified API can greatly assist in achieving your desired outcomes. Following the steps outlined in this blog should help you implement collate en_us.UTF-8 effectively in your Sequelize queries.

Remember to always test your queries to ensure they return the desired results, especially when dealing with collation and case sensitivity in your datasets. Happy coding!