However, this creates a problem when a decision must be made now and the information required to make it will not be produced until the end of the week. The objective of a popular query language is to provide users with a dimple, natural language structure (like English) to select records from a database and produce information on demand. To be effective, a query language must allow the user to phrase requests for information in a flexible fashion.
For example, take a request for inventory information. Here are some examples, take a request for inventory information. Here are some examples of questions that the user could ask using a popular query language when a single file is involved:
- List all items in the inventory database for which the quantity on hand equals 10 (Immediate orders would have to be placed to restock these items.)
- List all items in the database for which the quantity on hand is less than or equal to the reorder point. (This information would be used to process regular orders for restocking inventory.)
- List the names and addresses of all customers who ordered items that were out of stock and now are in stock. (This would involve using the customer order file and the inventory file and would show a listing of all customers who should be notified by mail that the items they ordered are now available for pickup.)
- List the phone numbers of customers who ordered items that were out of stock and that aren’t going to be restocked. (This would also involve using both the customer order file and the inventory file and would show a listing of all phone numbers of customers who should be notified that the item they ordered will no longer be carried in inventory.)