Cassandra Practice Test

What operation is demonstrated by the command "INSERT ... IF NOT EXISTS"?

1. Updating existing data

2. Inserting data only if a condition is met

3. Deleting data if certain conditions are fulfilled

4. Reading data without altering it

The correct answer is: Inserting data only if a condition is met

The command "INSERT ... IF NOT EXISTS" is used in Cassandra to perform a conditional insert operation. This means that the command will insert data into the database only if the specified condition—namely, that the data does not already exist—is satisfied. When using this command, if the data you are trying to insert already exists in the specified table, the operation will not proceed with the insertion, thereby preventing duplicate entries. This is particularly useful in scenarios where maintaining data integrity and uniqueness is critical. By employing this command, developers can ensure that they are adding new records without accidentally overwriting or duplicating existing ones. In contrast, the other options do not accurately describe the function of this command. For instance, it does not perform updates to existing data; rather, it checks for existence prior to inserting new data. Furthermore, it does not involve deleting data, nor does it read data without making changes, as its primary role is to conditionally insert based on the existence of data.