Reference no: EM133445850
Questions
1. What is the restrict operation?
An operation that asks a DBMS to copy specific attributes.
An operation that asks a DBMS to ignore null values.
An operation that asks a DBMS to choose rows that meet some logical criteria.
An operation that asks a DBMS to choose columns that meet some logical criteria.
2. The _____ operation creates a new table by placing all rows from two source tables into a single result table.
3. The _____ operation combines two tables into one using relationships between primary and foreign keys.
4. Which of the following is true regarding joins? Select all that apply.
Most joins between tables that do not have a primary key-foreign key relationship are not valid.
Joins between tables that do not have a primary key-foreign key relationship are valid in most circumstances.
Outer joins are not valid.
Invalid joins can create misinformation.
5. Which of the following regarding unions is false?
For a union operation to be possible, the two source tables must be union compatible.
For a union operation to be possible, columns from both tables must be defined over the same domains.
Tables in a union operation must have the same columns.
Tables in a union operation must have columns of identical order and size.
6. Which of the following regarding joins is true?
A join can be a strain on database resources.
The most common join is an outer join.
A join's usefulness stems from its ability to merge database files.
Joins are facilitated through relationships between primary keys.
7. What is a database relation?
The creation of a database file
The definition of a database table with columns and rows
The creation of a database field
The definition of a database form
8. Which of the following characterizes a column in a relation?
A name that is unique within the table
Values drawn from one and only one domain
A name that is unique within the database
Domain constraints
9. Which of the following characterizes a row in a relation?
Uniqueness
A primary key
Multivalued attributes
Domain constraints
10. Which of the following regarding the way columns and rows can be viewed is true?
Column and rows are positional and must be viewed in the defined order.
Columns are positional and must be viewed in the defined order; rows can be viewed in any order.
Rows are positional and must be viewed in the defined order; columns can be viewed in any order.
Columns and rows can be viewed in any order.
11. Which of the following regarding the representation of data relationships in a relational database is true?
Data should never be used to represent relationships.
Relations are documented by using examples containing appropriate data.
Only numeric data can be used to represent relationships.
Relations are documented by using examples containing primary key and/or foreign key data.
12. Which of the following is true regarding primary keys in a relational database?
Unique primary keys make it possible to identify every row in a table.
Any bit of data can be located by referencing the name of the table and the primary key of the row.
In certain circumstances, a primary key may contain a null vale.
A relation can only have one primary key.
13. Which of the following would make the most effective primary key in a patient contact information table?
Patient-selected values they will easily remember.
Concatenated codes based on patient initials and dates of birth.
Arbitrary numbers.
Patient email addresses.
14. Which of the following is true regarding the representation of data relationships?
A foreign key should not be used to represent a data relationship.
Relationships can be represented between tables and/or files.
Relationships can be represented between tables only.
A concatenated key should not be used to represent a data relationship.
15. What is referential integrity?
A constraint stating that every nonnull foreign key value must match an existing key value.
A constraint stating that a primary key must not contain a null value.
A feature of relational databases that ensures the existence of a primary key.
A feature of relational databases that enforces usage of appropriate data types.