DP-900 Describe core data concepts Practice Test 9 — 15 Questions

Question 1

A company stores customer data in a SQL table with fixed columns (CustomerID, Name, Email, SignupDate). They also store product images as JPEG files and application logs as JSON documents. Which of the following correctly classifies each data type?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

SQL table: structured, JPEG: unstructured, JSON: semi-structured. A SQL table with fixed columns enforces a rigid schema, making it structured data. JPEG files are binary blobs with no internal schema, classifying them as unstructured. JSON documents use key-value pairs with flexible schemas, which is the definition of semi-structured data.

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SQL table: structured, JPEG: semi-structured, JSON: unstructured

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SQL table: semi-structured, JPEG: unstructured, JSON: structured

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SQL table: unstructured, JPEG: structured, JSON: semi-structured

Question 2

A retail company uses a point-of-sale (POS) system that records each sales transaction in a database. Each transaction involves reading the current inventory, updating the stock level, and recording the sale. The database must ensure that concurrent transactions do not interfere with each other, so that one transaction does not see partially updated data from another. Which property of a database transaction ensures this isolation?

Accepted Answer

Isolation. Isolation ensures that concurrent transactions do not interfere with each other, so each transaction sees a consistent snapshot of the database as if it were the only transaction running. In the POS scenario, isolation prevents one transaction from reading partially updated inventory data from another transaction, which could lead to overselling or stock discrepancies. This property is typically implemented through locking mechanisms or multi-version concurrency control (MVCC).

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Atomicity

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Consistency

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Durability

Question 3

A company updates a customer's address in a database. The update must ensure that all existing orders still reference a valid customer ID. The database checks the foreign key constraint and rejects the update if it would violate referential integrity. Which ACID property does this enforcement represent?

Accepted Answer

Consistency. Consistency ensures that any database transaction brings the database from one valid state to another, preserving all defined rules, including constraints like foreign keys. In this scenario, the foreign key constraint enforcement prevents an update that would leave orphaned order records, directly upholding the consistency property by rejecting the transaction if it violates referential integrity.

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Atomicity

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Isolation

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Durability

Question 4

A company receives data from a point-of-sale system. Each row contains TransactionID, ProductID, Quantity, and Price. The data has a fixed schema and is stored in a table. How should this data be classified?

Accepted Answer

Structured data. The data has a fixed schema with clearly defined columns (TransactionID, ProductID, Quantity, Price) and each row follows the same structure, which is the definition of structured data. In Azure, this would map directly to a table in Azure SQL Database or a fixed-schema table in Azure Synapse Analytics. The rigid schema and consistent data types make it ideal for relational storage and querying.

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Semi-structured data

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Unstructured data

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Transactional data

Question 5

A retail company stores customer transaction data in a relational database. Each transaction is recorded with a fixed schema including TransactionID, CustomerID, ProductID, Quantity, and TotalAmount. Which type of data does this represent?

Accepted Answer

Structured data. The data conforms to a fixed schema with defined columns (TransactionID, CustomerID, ProductID, Quantity, TotalAmount) and data types, which is the defining characteristic of structured data. In a relational database, this schema enforces consistency and allows for efficient querying using SQL, making it a classic example of structured data.

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Unstructured data

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Semi-structured data

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Binary data

Question 6

A global e-commerce platform uses a combination of relational and NoSQL databases. The order management system requires ACID transactions across multiple tables (Orders, OrderItems, Inventory). The product catalog uses a flexible schema to accommodate varying product attributes and is read-heavy. The session store requires low-latency key-value lookups with eventual consistency. Which of the following pairings of data stores best matches these requirements?

Accepted Answer

Order management: Azure SQL Database - Product catalog: Azure Cosmos DB (NoSQL API) - Session store: Azure Cache for Redis. Azure SQL Database provides full ACID transaction support across multiple tables, making it ideal for order management. Azure Cosmos DB (NoSQL API) offers a flexible schema and high read throughput for the product catalog. Azure Cache for Redis delivers sub-millisecond key-value lookups with eventual consistency, perfect for session storage.

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Order management: Azure Cosmos DB (NoSQL API) - Product catalog: Azure SQL Database - Session store: Azure Table Storage

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Order management: Azure Table Storage - Product catalog: Azure SQL Database - Session store: Azure Cosmos DB (NoSQL API)

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Order management: Azure Cosmos DB (Table API) - Product catalog: Azure Cache for Redis - Session store: Azure SQL Database

Question 7

A company stores customer information in a SQL database table with columns: CustomerID, FirstName, LastName, Email, SignupDate. They also store product images as JPEG files in Azure Blob Storage. Which statement correctly describes the types of data involved?

Accepted Answer

Customer data is structured, product images are unstructured.. Customer data stored in a SQL database table with defined columns (CustomerID, FirstName, LastName, Email, SignupDate) is structured because it adheres to a fixed schema with rows and columns. Product images stored as JPEG files in Azure Blob Storage are unstructured because they lack a predefined data model and are stored as binary large objects (BLOBs) without a schema. Option B correctly identifies this distinction.

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Customer data is unstructured, product images are semi-structured.

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Both are structured.

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Customer data is semi-structured, product images are unstructured.

Question 8

A financial database system ensures that once a transaction is committed, the data changes are permanently stored and will survive any subsequent system failure, such as a power outage or crash. Which property of ACID transactions does this describe?

Accepted Answer

D: Durability. D is correct because durability guarantees that once a transaction is committed, the changes persist permanently, even in the event of a system failure like a power outage or crash. In SQL Server, this is implemented via the write-ahead log (WAL) and checkpoint processes, ensuring committed data is flushed to disk before acknowledging success.

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A: Atomicity

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B: Consistency

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C: Isolation

Question 9

A financial company needs to store transactional records where each record has a fixed set of attributes (TransactionID, Amount, Date, AccountID). The data must support complex queries and enforce referential integrity. Which type of data store is most appropriate?

Accepted Answer

Relational database. A relational database (option C) is the most appropriate choice because transactional records with a fixed schema and the need for referential integrity (e.g., ensuring AccountID references a valid account) are best handled by a structured, ACID-compliant system like Azure SQL Database or SQL Server. Relational databases enforce constraints such as foreign keys and support complex queries using JOINs and aggregations, which are essential for financial reporting and auditing.

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Key-value store

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Document database

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Graph database

Question 10

A hospital stores patient records. Each record includes a PatientID (integer), Name (text), DateOfBirth (date), and MRI scan images (binary files). Which classification best describes the MRI scan images?

Accepted Answer

Unstructured data. MRI scan images are binary files that lack a predefined data model or schema, making them unstructured data. Unlike structured data (e.g., rows in a SQL table) or semi-structured data (e.g., JSON with tags), binary image files cannot be easily queried or organized using traditional relational database tools without additional processing.

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Structured data

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Semi-structured data

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Streaming data

Question 11

A company stores customer orders. Each order has a unique order ID, customer ID, a list of items (each item contains product ID, quantity, and price), and an order date. They frequently query orders by customer ID and also need to filter by order date ranges. The data volume is high and schema flexibility is desired because items can vary in structure. Which type of data store is best suited for this scenario?

Accepted Answer

Document database. A document database (e.g., Azure Cosmos DB for NoSQL) is ideal because it stores each order as a self-contained JSON document, allowing the items array to vary in structure per order (schema flexibility). It supports efficient queries by customer ID (using a partition key) and filtering by order date ranges (using indexing on the date field), while handling high data volumes with horizontal scaling.

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Relational database

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Key-value store

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Graph database

Question 12

A company stores an employee database in a relational database. The Employees table includes columns: EmployeeID (integer), FirstName (text), LastName (text), HireDate (date), and a column called Photo which stores the employee's photo as a binary large object (BLOB). Which statement best describes the data types in this table?

Accepted Answer

The Photo column stores unstructured data, while the other columns store structured data.. The Photo column stores a binary large object (BLOB), which is unstructured data because it does not have a predefined schema or format that can be easily queried or indexed by relational operations. In contrast, EmployeeID, FirstName, LastName, and HireDate are all structured data types (integer, text, date) that conform to a fixed schema and support direct querying, sorting, and indexing. This distinction is fundamental in Azure data services, where structured data is typically stored in Azure SQL Database or Azure Synapse, while unstructured BLOBs are better suited for Azure Blob Storage.

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All columns store structured data.

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All columns store unstructured data.

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The HireDate column stores semi-structured data.

Question 13

A company processes sales transactions in real-time from a retail website. Each transaction is recorded as a row in a relational database. Additionally, the company stores weekly sales reports as PDF files. Which statement correctly describes these data types?

Accepted Answer

Transactions are structured, reports are unstructured.. Transactions are structured because they are stored as rows in a relational database, which imposes a fixed schema with defined columns and data types. Weekly sales reports as PDF files are unstructured because they lack a predefined data model and cannot be easily queried using SQL without additional processing. Option B correctly identifies this distinction.

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Transactions are unstructured, reports are semi-structured.

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Both are structured because they are files.

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Both are unstructured because they are digital.

Question 14

A database system ensures that a transaction either completes fully and all changes are applied, or it is completely rolled back and no partial changes are saved. Which property of ACID transactions does this describe?

Accepted Answer

Atomicity. Atomicity ensures that a transaction is treated as a single, indivisible unit of work. If any part of the transaction fails, the entire transaction is rolled back, leaving the database in its original state. This property guarantees that no partial changes are saved, which directly matches the description in the question.

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Consistency

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Isolation

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Durability

Question 15

A company stores customer data in a SQL table with fixed columns (CustomerID, Name, Email, SignupDate). They also store product images as JPEG files and application logs as JSON documents. Which of the following correctly classifies each data type?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Structured data. This data is structured because it conforms to a fixed schema with clearly defined columns (CustomerID, Name, Email, SignupDate) and data types (integer, varchar, date). In SQL Server, structured data is stored in tables with rows and columns, enabling efficient querying via T-SQL and indexing. The consistent adherence to the schema across all rows is the hallmark of structured data.

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Unstructured data

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Semi-structured data

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Transactional data