programming
beginner
10 sample questions
Schemas MCQ Practice Test
Logical structure that defines how database tables, views, and other elements are organized.
Q1. What is the main purpose of a schema in a database?
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A. To store data
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B. To define the structure of data ✓
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C. To query data
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D. To index data
Explanation: A schema is a blueprint or a design that defines the organization of data within a database. It specifies the relationships between different data elements, such as tables, columns, and data types.
Q2. In a database schema, what is the purpose of a "Primary Key" constraint?
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A. To enforce data integrity by uniquely identifying each record in a table ✓
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B. To ensure data consistency by preventing duplicate values in a column
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C. To improve query performance by indexing a frequently used column
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D. To enforce referential integrity by linking related tables
Explanation: A primary key constraint is used to uniquely identify each record in a table, preventing duplicate values and ensuring data integrity.
Q3. What is the primary purpose of a schema in a database?
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A. To store data
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B. To define the structure of data ✓
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C. To perform data retrieval
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D. To enforce data integrity
Explanation: A schema is a blueprint or a design that defines the structure of a database, including the relationships between tables and the data types of each column.
Q4. In a relational database, which of the following is a characteristic of a schema?
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A. A schema is a physical storage of data.
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B. A schema is a collection of related tables. ✓
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C. A schema is a way to store data in a hierarchical structure.
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D. A schema is a set of predefined rules for data integrity.
Explanation: In a relational database, a schema refers to the overall structure of the database, including the relationships between various tables. It defines the relationships between entities, attributes, and data types, and is a crucial aspect of database design.
Q5. In a relational database schema, what is the purpose of a primary key in a table?
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A. to enforce data consistency
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B. to establish a relationship between tables
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C. to uniquely identify each record in a table ✓
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D. to determine the order of records in a table
Explanation: A primary key is a field or set of fields in a table that uniquely identifies each record. It ensures that each record is distinct and can be easily located and retrieved.
Q6. In a relational database schema, what is the primary purpose of a "bridge table"?
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A. to establish a one-to-one relationship between two entities
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B. to establish a many-to-many relationship between two entities ✓
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C. to establish a primary key in a table
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D. to establish a foreign key in a table
Explanation: A bridge table, also known as a junction table, is used to resolve many-to-many relationships between two entities in a relational database schema. It acts as a bridge between the two tables, allowing multiple relationships between them.
Q7. A database schema is a visual representation of the database structure, including the relationships between tables. Which of the following is a key characteristic of a well-designed schema?
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A. It should be normalized to prevent data redundancy. ✓
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B. It should be denormalized to improve query performance.
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C. It should be highly normalized but not denormalized.
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D. It should be as simple as possible but no simpler.
Explanation: A well-designed schema should be normalized to prevent data redundancy, which means that each piece of data is stored in one place and one place only. This helps to maintain data consistency and prevent errors.
Q8. In a relational database schema, what is the primary purpose of a table's primary key?
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A. To uniquely identify each row in a table ✓
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B. To define the relationships between tables
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C. To enforce data integrity by preventing duplicate values
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D. To improve query performance by indexing data
Explanation: A primary key is a column or set of columns in a table that uniquely identifies each row within that table. It serves as a unique identifier for each record, allowing for efficient data retrieval and manipulation.
Q9. Which of the following is a characteristic of a schema in a database?
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A. A schema is a physical storage structure.
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B. A schema is a collection of all the data in a database.
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C. A schema is a logical structure that defines the organization of data within a database. ✓
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D. A schema is a query that retrieves specific data from a database.
Explanation: A schema in a database defines the organization of data, including the relationships between different data elements. It provides a logical structure for the data, which is independent of the physical storage structure.
Q10. Which of the following is a benefit of using a normalized database schema?
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A. Reduced data redundancy ✓
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B. Improved data consistency
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C. Increased data complexity
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D. Enhanced data security
Explanation: A normalized database schema reduces data redundancy by storing each piece of data in one place and one place only, making it easier to maintain and update the data.
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