1. What is the in deletion method
The in deletion method usually uses an array containing multiple values as a condition, and deletes those conditions in the database of multiple records. For example, the following SQL statement:
DELETE FROM user WHERE id IN (1, 2, 3, 4, 5);
The ids in the user table are 1, 2, 3, 4, 5 records will be deleted from the SQL statement. This one-by-one deletion method is based on the idea of SQL statements, which makes it more convenient for us to perform this operation.
2. How to use the in delete method
In ThinkPHP, the use of the in delete method is very simple. You only need to call the delete method of the model and pass in a file containing An array of multiple values will do. Here is a sample code:
$user = new UserModel();
$ids = array(1, 2, 3, 4, 5);
$result = $user-> where('id', 'in', $ids)->delete();
We first instantiate a UserModel, assign it to the $user variable, and then define a $ids array, It contains multiple id values. Next, we called the where method of $user, passing in 'in' as the comparison operator and the $ids array, indicating that the user ID is any record in the $ids array. Finally, we use the delete method to delete the records that meet the conditions and store the results in the $result variable.
3. Application scenarios of in deletion method
The in deletion method is very useful in many scenarios. For example, we can use the in delete method to delete all articles under a specific category, or delete multiple users. The following are some common application scenarios of the in deletion method:
1. Delete users in batches
Suppose we have a user management system and need to delete multiple users in batches. We can use the in delete method to achieve this function. The code example is as follows:
$user = new UserModel();
$ids = array(1, 2, 3, 4, 5);
$result = $user->where('id', 'in', $ids)->delete();
This code will delete IDs 1, 2, 3, 4, 5 user records.
2. Batch deletion of articles
If we need to delete all articles under a certain category at one time, we can consider adding a batch deletion function to the blog system. We can use the in delete method to achieve this function. The code example is as follows:
$article = new ArticleModel();
$ids = array(21, 22, 23, 24, 25);
$result = $article->where('category_id', 10)->where('id', 'in', $ids)->delete();
This code will Delete the article records with category ID 10 and IDs 21, 22, 23, 24, and 25.
4. Notes
1. The deletion method can only delete multiple records that meet a certain condition, but cannot delete the entire table.
2. When using the in deletion method, please note that the parameter passed is an array, and the array must contain multiple values.
3. When using the in delete method, be sure to pay attention to the security of parameters to avoid risks such as SQL injection.
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