Interactive Query Computation
The decision support is based on the query computations on the existing database. The interactive query is the basic need of end users. The accurate and complete retrieval conditions can help user get the required data from the database.
At present, there are two kinds of interactive query solutions:
1. Regarding the tools for interactive query computation, the most common tool is SQL statement querying directly on the database. But, using SQL or stored procedure to query will bring about various troubles. First, users must grasp the database structure and know the name of every table and their relations, just like a database administer. Second, SQL as a generic query language is quite awkward to process the complicated computation: Using SQL to carry out the programmed computation, the developer may be unable to carry through the computation or have to write a long string of complicated statements.
2. The interactive computation can also be implemented by programming directly. But this method will result in a much higher difficulty and great workload if compared with using SQL. Moreover, the program is not suitable to modify once programming is completed. You will be unable to handle it timely if the business logic changes or there is a new computation task
We may need to obtain some useful information by analyzing and computing from time to time, based on the raw data fragment in the database, such as:
Is there any stock rising to the expected value for three consecutive business days in a month?
What are the top n clients achieving half of total sales?
Is there any goods sold out for at least 3 times by PM 5 in a month?
What is the average interval between the purchases of iPhone and later the iPad by a same customer?
Is there any subscriber run out of credit to pay the telephone bill?