In a database table, what does a 'row' represent?
A column header describing the data type.
A relationship between two different tables.
A unique record or instance within the table.
A specific attribute or characteristic of an entity.
What is the purpose of a referential integrity constraint in a relational database?
To enforce relationships between tables by ensuring that related data exists
To speed up data retrieval queries
To ensure that all data in a table is unique
To prevent unauthorized access to sensitive data
A table has a composite primary key (using two columns). What condition must be met for it to be considered in Second Normal Form (2NF)?
It must already be in 1NF
No non-key attribute should be dependent on only part of the primary key
It must have no transitive dependencies
All columns must have unique values
How is a one-to-many relationship represented in an ER diagram?
Two lines connecting two entities
A line with a crow's foot symbol on one end and a single line on the other
A diamond connecting two entities
A single line connecting two entities
What happens to records in the 'Orders' table with 'ON UPDATE CASCADE' if a customer's ID is updated in the 'Customers' table?
The corresponding customer IDs in the 'Orders' table are automatically updated.
The corresponding orders are deleted from the 'Orders' table.
An error occurs, and the update operation on the 'Customers' table is rolled back.
The 'Orders' table is unaffected, and the old customer ID remains.
Which of the following is NOT a valid SQL data type for storing numerical values?
VARCHAR
INTEGER
DECIMAL
FLOAT
What is the primary purpose of a Primary Key in a database table?
To uniquely identify each row within the table.
To establish a relationship with another table.
To define the order in which data is stored.
To ensure that all columns in the table have a value.
Which normal form acts as the foundation for higher levels of normalization?
Boyce-Codd Normal Form (BCNF)
Third Normal Form (3NF)
Second Normal Form (2NF)
First Normal Form (1NF)
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 table with a composite key, a non-key attribute depends on only one part of the key. Which normal form is violated?
None of the above