What is the key difference between a database and a schema?
A database is a collection of tables, while a schema defines the structure of a single table.
A database stores the actual data, while a schema defines the rules for accessing that data.
A database is a broader concept encompassing one or more schemas, each defining a logical structure within the database.
There is no difference; the terms are interchangeable.
Referential integrity ensures that...
all columns in a table have unique values.
relationships between tables remain consistent.
queries are optimized for performance.
data is backed up regularly.
In a database table, what does a 'row' represent?
A specific attribute or characteristic of an entity.
A unique record or instance within the table.
A relationship between two different tables.
A column header describing the data type.
What does the 'ON DELETE CASCADE' constraint do?
It sets the foreign key values in the child table to NULL when a record in the parent table is deleted.
It prevents deletion of records in the parent table if there are matching records in the child table.
It has no impact on the child table when a record in the parent table is deleted.
It automatically deletes matching records in the child table when a record in the parent table is deleted.
What is the PRIMARY purpose of using indexes in a database?
To speed up data retrieval operations
To enforce data integrity constraints
To improve data security
To reduce disk space consumption
Which of the following is a key benefit of using a well-designed schema for a data warehouse?
Simplified data loading from various sources
Improved query performance and efficiency
Increased data redundancy for backups
Reduced need for data modeling and analysis
In which scenario might a Snowflake Schema be preferred over a Star Schema?
When data integrity is critical, and redundancy needs to be minimized
When storage space is a major concern
When dealing with small datasets
When query performance is the top priority
When converting an ER diagram to a database schema, what does an entity typically become?
A column
A database
A row
A table
To change the data type of a column in an existing table, which clause should be used with the ALTER TABLE statement?
CHANGE COLUMN
TRANSFORM COLUMN
UPDATE COLUMN
MODIFY COLUMN
You have a table with columns for StudentID, StudentName, CourseID, and CourseName. StudentID determines StudentName, and CourseID determines CourseName. What normal form is this table in?
First Normal Form (1NF)
Second Normal Form (2NF)
Third Normal Form (3NF)
None of the above