Exam 2: The Relational Model 1: Introduction, QBE, and Relational Algebra

The comparison operators are also known as relational operators.

You can restrict the output from a join to include only certain columns by using the ____ command.

When a structure satisfies all the properties of a relation except for the first item-in other words,some entries contain repeating groups and thus are not single-valued-it is referred to as a(n) ____________________.

When a field name contains spaces or SQL reserved words,you must enclose the field name in curly braces ({}).

A relation is essentially just a two-dimensional table.

Access automatically adds double quotation marks around values in the design grid that are formatted as Text fields when you run the query or move the insertion point to another cell in the design grid.

A relational database handles entities,attributes,and relationships by storing each entity in its own table.

Using the product operator,if table A has 4 rows and table B has 4 rows,the number of rows in the product of these two tables is ____.

The secondary key provides an important way of distinguishing one row in a table from another.

The product of two tables is also called the ____ product.

The ____ operator is used to concatenate every row in the first table with every row in the second table.

If you are sorting records by more than one field,the more important field is called the ____.

The comparison operators are +,*,%,and /.

The relationships between tables are handled through ____________________ columns.

The ____ operator is performed by the SUBTRACT command in relational algebra.

QBE is a visual approach to writing queries.

To find the total of all customers' balances,use the ____________________ function.

Columns in a table are often called attributes or ____________________.

What is the difference between an AND criterion and an OR criterion? How is each criterion created in QBE?

Count,Sum,Avg,Max,and Min are a few of the built-in statistics or ____ functions that can be used in a query.