TypeScript knows your SQL is broken before your tests even run

The idea of using TypeScript and language server plugins to catch SQL errors before runtime is fascinating. It can indeed prevent many common issues such as incorrect parameter counts, missing keywords like FROM or SET, and even more subtle structural problems.

Example Use Case

Let's consider a real-world example where a type system could have caught an error:

Scenario: Missing WHERE Clause in Update Statement

Imagine you're working on a user management system. You need to update the email address of a specific user based on their ID. However, due to a typo or oversight, you forget to include the WHERE clause.

Incorrect SQL Query:

typescript
 
1const updateUserEmail = sql`
2  UPDATE users SET email = '[email protected]' 
3`;

If this query is executed without validation, it will update the email of all users in the database. This could be disastrous!

How a Type System Could Catch It

With the proposed type system and language server plugin:

1. Type Validation: The SQLParams type would validate that every SQL statement has all necessary components (e.g., WHERE clause for update statements).
2. Language Server Plugin: As you write your SQL

Read the full article at DEV Community

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