Why is it important to keep your database up to date and organized? What type of data might become unneeded or unwanted over time? What type of query can help you clean up your database?

What will be an ideal response?

In order to use queries effectively, the data must be kept current and up to date. Using incorrect data can be expensive. For example, duplicate mailings sent to the same customer, or mailings sent to customers who have moved, may lead to redoing the mailing or losing customers. Databases can accumulate data over time, and sometimes that data can become out of date, or maybe it was just entered wrong in the first place. Products may be discontinued or employees may be fired. Duplicate data can be mistakenly added. Older data may need to be archived and moved from one database to another. Data cleansing is a process where the delete query will remove data that is not useful or needed anymore. A delete query can delete data from one table while a complex delete query can delete related data from multiple tables.