How does Oracle determine if a field is not empty or an empty string?

In Oracle, you can use the following methods to determine if a field is empty or an empty string:

1. Utilize NULL condition testing.
2. Retrieve all records from a table where a specific column is not empty.
3. Use the LENGTH function to determine the length of a string:
4. Retrieve all rows from a table where the length of a specific column is greater than zero.
5. Use the TRIM function to determine the length of the string after removing spaces.
6. Retrieve all columns from the table where the length of the trimmed column is greater than 0.
7. Convert empty strings to NULL using the NVL function, and then use NULL condition checking.
8. Select all columns from the table where the specified column is not empty.

These methods can be chosen based on the needs to determine if a field is empty or an empty string.