Javascript TypeORM MissingDeleteDateColumnError
Understanding TypeORM and Its Purpose
TypeORM is a popular Object-Relational Mapper (ORM) for TypeScript and JavaScript (ES7, ES6, ES5). It is designed to work with various databases such as MySQL, PostgreSQL, MariaDB, SQLite, and more. TypeORM allows developers to interact with databases using TypeScript or JavaScript classes and decorators, providing a more intuitive and object-oriented approach to database management.
Identifying the Symptom: MissingDeleteDateColumnError
When working with TypeORM, you might encounter the MissingDeleteDateColumnError. This error typically occurs when you attempt to use soft delete functionality in your entity but have not defined a delete date column. The error message is a clear indication that TypeORM is expecting a specific column to track deletion timestamps, which is missing in your entity definition.
Explaining the Issue: Why the Error Occurs
The MissingDeleteDateColumnError arises because TypeORM's soft delete feature requires a column to store the deletion timestamp. This column is used to mark records as deleted without actually removing them from the database. If you enable soft delete by using the @DeleteDateColumn decorator, TypeORM expects this column to be present in your entity. Without it, TypeORM cannot track which records are considered deleted, leading to the error.
Soft Delete in TypeORM
Soft delete is a technique where records are not physically removed from the database but are instead marked as deleted. This is useful for maintaining historical data and allowing for record recovery. In TypeORM, this is achieved using the @DeleteDateColumn decorator, which automatically manages the deletion timestamp.
Steps to Fix the MissingDeleteDateColumnError
To resolve the MissingDeleteDateColumnError, you need to define a delete date column in your entity. Follow these steps:
Step 1: Add the Delete Date Column
import { Entity, PrimaryGeneratedColumn, Column, DeleteDateColumn } from 'typeorm';
@Entity()
export class User {
@PrimaryGeneratedColumn()
id: number;
@Column()
name: string;
@DeleteDateColumn()
deletedAt: Date;
}
In the example above, the @DeleteDateColumn() decorator is used to define the deletedAt column, which will store the timestamp of when the record is marked as deleted.
Step 2: Run Migrations
After adding the delete date column, you need to update your database schema. If you are using TypeORM migrations, generate a new migration and run it:
typeorm migration:generate -n AddDeleteDateColumn
typeorm migration:run
These commands will create and apply a migration to add the deletedAt column to your database table.
Step 3: Verify the Fix
Once the migration is applied, verify that the deletedAt column is present in your database table. You can now use TypeORM's soft delete functionality without encountering the MissingDeleteDateColumnError.
Additional Resources
By following these steps, you should be able to resolve the MissingDeleteDateColumnError and effectively utilize soft deletes in your TypeORM project.
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