Database Systems I

Characteristic of database management system which allows program operation independence and program data independence is classified as

• Conceptual abstraction

• Implementation abstraction

• Data abstraction

• Interface abstraction

Which statement is wrong about PRIMARY KEY constraint in SQL?

• The PRIMARY KEY uniquely identifies each record in a SQL database table

• Primary key can be made based on multiple columns

• Primary key must be made of any single columns

• Primary keys must contain UNIQUE values.

The DROP TABLE statement:

• deletes the table structure only.

• deletes the table structure along with the table data.

• works whether or not referential integrity constraints would be violated

• is not an SQL statement

SQL Query to delete all rows in a table without deleting the table (structure, attributes, and indexes)

• DELETE FROM table_name;

• DELETE TABLE table_name;

• DROP TABLE table_name;

• NONE

Data administrators are responsible for:

• Physical database design

• Managing technical issues in the database environment

• Overall management of data resources in an origination

• Writing application programs

What is Entity relationship model?

• An item about which information is stored in the database

• The model that focuses on representing the data as it exists in the real world

• The models that identify the data that different groups will need and eventually translate into forms and reports

• Characteristics attached to each entity.

The graphic below indicates;

• That student can own many cars

• A student can own many cars and a car can be owned by many students

• A student cannot own a car

• A car can be owned by many students

Relational databases

• Enable one “fact” to be stored in “one place”

• Save disk storage space

• Incur a processing overheard when carrying out queries

• Only work in a windows environment.

A foreign key is which of the following;

• A defined attribute in all tables within the database

• The same as a primary key

• An attribute that serves as the primary key of another relation

• An attribute that serves no purpose

The set of rules that govern the internal validity and consistency of data within a relational database are known as:

• Rules of referential integration

• Rules of data integration

• Rules of referential integrity

• Rules of data integrity