Learning C# 3.0

Chapter 20: ADO.NET and Relational Databases

Quiz Solutions

Solution to Question 20-1. In a relational database, the data is organized into tables, and the queries are defined by the relationships among the tables.

Solution to Question 20-2. A primary key is a column that contains values that are unique to the table in which it resides, which allows you to uniquely identify each row.

Solution to Question 20-3. A foreign key is a column in a table that is also the primary key in a different table. This allows you to identify the relationship among the tables.

Solution to Question 20-4. To retrieve the contents of the Title column in the Books table the appropriate query would be:

Select Title from Books

Solution to Question 20-5. To retrieve the contents of the Author column where the value in the Publisher column is “OReilly”, the appropriate query would be:

Select Author from Books where Publisher = 'OReilly'

Solution to Question 20-6. You would want to use a join when you want to filter the information retrieved from one table based on the contents of a different table.

Solution to Question 20-7. The DataSet object represents a subset of retrieved data, and can be used to view or manipulate the data.

Solution to Question 20-8. One good way to view the rows in a DataTable object is to iterate over the Rows collection with a foreach loop.

Solution to Question 20-9. The DataAdapter class provides the bridge between your application and the database. The DataAdapter can take a connection string ...