Identify the level within a database system (user, programmer of application software, and designer of the DBMS software) at which each of the following concerns or activities occur:
a. How should data be stored on a disk to maximize efficiency?
b. Is there a vacancy on flight 243?
c. Could a relation be stored as a sequential file?
d. How many times should a user be allowed to mistype a password before the conversation is terminated?
e. How can the PROJECT operation be implemented?
Typically users interact with application software which then interacts with the DBMS. This maintains a high level of abstraction between the different layers. This abstraction is what makes a database system so powerful and flexible.
A database system can be envisioned as having three levels:
- The user layer refers to the user who is inserting or reading data from the database. The user "cares" about the data and nothing else. In particular, the user doesn't care about how the data is stored (e.g., one big table vs. a bunch of small tables) or how the data is retrieved.
- The application software level is where software that uses the database sits. In ...
This solution looks at five different aspects of a database software system and explains where each aspect fits in the various database system levels. This solution is 413 words.