How can access prevent duplicate data from being entere…

There are several ways to prevent duplicate data entry:

1. Unique constraint in a database ensures that a column or combination of columns in a table does not allow duplicate values. When attempting to insert duplicate data, the database will throw an exception. The specific method may vary depending on the type of database, for example, in MySQL, you can use the UNIQUE keyword to create a unique constraint.
2. In programming languages, data structures like Sets can be used to store data because they do not allow duplicate elements. Before inserting new data, it is important to check if it already exists in the set to prevent duplicates.
3. Front-end validation: In the front-end page, you can use script languages like JavaScript to validate user input. By listening to user input events, prompt and prevent submission when attempting to input duplicate data.
4. Back-end validation: Data validation performed on the server side allows for checking data before it is submitted by the user. If duplicate data is detected, an error message can be returned to reject the storage.

The above methods can be used individually or in combination to enhance the detection of data repetition and prevent input.