CSE 100: Quiz No. 4

1. The relational database model, which we have been discussing in class and which is the basis for Access, Oracle, dBase, and other commercial database systems, represents information as tables. The rows of the tables are known as    records   . The columns of the tables are known as    fields   . A database design---the names of the tables, the names of their columns, the data types of the entries and the relationships among various columns of different tables---is known as a database    schema    and is often contrasted with a database instance.

2. Database design seeks to avoid redundancy, the repeated occurrence in tables of the same information. The secondary reason for not wanting redundancy in a database is that it wastes computer memory (disk space, mostly) to store all of the replicated data. What is the primary reason to avoid redundancy?

   Inconsistency is the primary reason: If information appears in more than one place in the database, it can become inconsistent, e.g. if it is changed in one place but not the other(s).

   
   
   

   

3. A key aspect of updating a database is not to make changes directly to the existing database, in case the process fails and leaves the existing database in a broken state. The standard alternative to directly changing it was illustrated by the preceding diagram. Fill in the two empty boxes.

4. The UW's STAR registration system is an example of a transaction processing system. We can guess that the table that STAR is constructing as students register for courses is called Registration. If Registration has rows with four values, what information would those entries likely represent? (The 4th has been filled in.)

      student number       course (SLN)       transaction ID (primary key)       grade   

   [These are not the only acceptable responses.]