Deleting Records

note

Deleting records is a fundamental operation to manage the lifecycle of data within your application. The CollectModel class provides methods to delete multiple records. We will use the Author and Post models defined earlier to demonstrate these operations.

Table of Contents

• Deleting Records
• Handling Related Records

delete

The delete method is used to remove multiple records based on specified criteria.

Signature:

delete(
  params?: Omit<CollectQuery<S>, 'labels'>,
  transaction?: CollectTransaction | string
): Promise<CollectApiResponse<{ message: string }>>;

Parameters:

• params (optional): An object specifying query parameters such as filters.
• transaction (optional): A transaction object or string to include the operation within a transaction.

Returns:

• A promise that resolves to a CollectApiResponse containing the result of the delete operation.

Examples:

Example with Author:

const transaction = await Collect.tx.begin();
try {
  const deleteResponse = await Author.delete({ where: { name: { $contains: 'Jane' } } }, transaction);
  await transaction.commit();
  console.log(deleteResponse);
  /*
  {
    success: true,
    message: 'Records deleted successfully.'
  }
  */
} catch (error) {
  await transaction.rollback();
  throw error;
}

Example with Post:

const transaction = await Collect.tx.begin();
try {
  const deleteResponse = await Post.delete({ where: { rating: { $lt: 3 } } }, transaction);
  await transaction.commit();
  console.log(deleteResponse);
/*
{
  success: true,
  message: 'Records deleted successfully.'
}
*/
} catch (error) {
  await transaction.rollback();
  throw error;
}

Deletion with Multiple Operators:

const deleteResponse = await Post.delete({
  where: {
    $OR: [
      { title: { $contains: 'Blog' } },
      { rating: { $gte: 4.5 } },
      { created: { $lt: '2023-01-01T00:00:00Z' } }
    ]
  }
});
console.log(deleteResponse);
/*
{
  success: true,
  message: 'Records deleted successfully.'
}
*/

Handling Related Records

When you delete a record that is attached to another record, the relationship is automatically removed. This ensures data integrity and consistency.

Complex Example with Transactions:

In this example, we'll delete an Author and ensure that any Post attached to this Author is also handled appropriately.

Steps:

1. Begin a transaction.
2. Delete the Author.
3. Verify that the related Post is updated accordingly.
4. Commit the transaction if the delete operation succeeds.
5. Rollback the transaction if any operation fails.

const transaction = await Collect.tx.begin();
try {
  // Step 1: Delete the author
  const deleteAuthorResponse = await Author.delete({ where: { __id: 'author_id' } }, transaction);
  
  // Step 2: Ensure related Post records are updated
  const relatedPosts = await Post.find({ where: { authorId: 'author_id' } }, transaction);
  for (const post of relatedPosts.data) {
    await Post.delete({ where: { __id: post.__id } }, transaction);
  }

  await transaction.commit();
  console.log(deleteAuthorResponse);
  console.log(relatedPosts);
/*
{
  success: true,
  message: 'Records deleted successfully.'
}
{
  data: [],
  total: 0
}
*/
} catch (error) {
  await transaction.rollback();
  throw error;
}

This complex example demonstrates how to manage related records within a transaction during delete operations.

Conclusion

This section covered how to delete records using the CollectModel class. By understanding these methods and their parameters, you can effectively manage your application's data lifecycle with the Collect SDK. The next sections will delve into other advanced operations and best practices.