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

Question 1

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?

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

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 2

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 3

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 4

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 5

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 6

A company stores customer data in a SQL Server database table with columns: CustomerID (integer), Name (varchar), Email (varchar), SignupDate (date). All rows adhere to this schema. Which type of data does this represent?

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

Question 7

A data file contains records for customer orders. Each record has fields for OrderID, CustomerID, and OrderDate that are present in every record. However, some records include an optional 'DiscountCode' field, and others include an optional 'GiftMessage' field. The file is stored in JSON format. Which type of data does this file represent?

Accepted Answer

Semi-structured data. The JSON file contains records with a fixed set of fields (OrderID, CustomerID, OrderDate) that are always present, but also includes optional fields (DiscountCode, GiftMessage) that may appear in some records but not others. This mix of a consistent schema with flexible, self-describing fields is the hallmark of semi-structured data. JSON itself is a semi-structured format because it uses key-value pairs and allows nested or optional attributes without requiring a rigid schema.

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Structured data

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Unstructured data

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Transactional data

Question 8

A company maintains a database of customer orders that are updated frequently. They also store aggregated monthly sales reports that are generated once and then only read. Which statement correctly distinguishes these two types of data workloads?

Accepted Answer

Transactional data is optimized for write operations, and analytical data is optimized for read operations.. Transactional workloads (like the frequently updated customer orders) are optimized for write-heavy operations, ensuring ACID compliance and data integrity, while analytical workloads (like the read-only monthly sales reports) are optimized for read-heavy operations, often using columnar storage or pre-aggregated data to speed up queries. This distinction aligns with the core difference between OLTP (Online Transaction Processing) and OLAP (Online Analytical Processing) systems in Azure, such as Azure SQL Database for transactional data and Azure Synapse Analytics for analytical data.

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Transactional data must always be stored in non-relational databases, and analytical data in relational databases.

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Analytical data always requires real-time processing, whereas transactional data is batch-processed.

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Transactional data is read-only and analytical data is frequently updated.

Question 9

Match each ACID property with its correct description. Properties: - Atomicity - Consistency - Isolation - Durability Descriptions: 1. Transactions appear to execute one after the other, even if they are concurrent. 2. Once a transaction is committed, the changes are permanently saved and survive failures. 3. A transaction either completes fully or is rolled back entirely. 4. A transaction brings the database from one valid state to another, obeying all rules. Which option correctly maps each property to its description?

Accepted Answer

Atomicity → 3, Consistency → 4, Isolation → 1, Durability → 2. It accurately maps each ACID property to its definition. Atomicity ensures a transaction is all-or-nothing (3), Consistency guarantees the database moves from one valid state to another (4), Isolation makes concurrent transactions appear serial (1), and Durability ensures committed changes persist even after a failure (2). These are the standard definitions used in Azure SQL Database and other relational database systems.

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Atomicity → 4, Consistency → 3, Isolation → 2, Durability → 1

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Atomicity → 2, Consistency → 1, Isolation → 3, Durability → 4

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Atomicity → 1, Consistency → 2, Isolation → 4, Durability → 3

Question 10

A manufacturing company stores two types of data: (1) real-time sensor readings from production machines used to monitor current machine status, and (2) historical daily production summaries used by managers to identify trends over months. Which statement accurately describes these workloads?

Accepted Answer

Sensor readings are an OLTP workload; daily summaries are an OLAP workload.. Real-time sensor readings involve frequent, small inserts and point lookups (typical of an OLTP workload), while historical daily summaries are aggregated data used for trend analysis over months (typical of an OLAP workload). OLTP systems handle high-volume transactional operations, whereas OLAP systems support complex queries and aggregations on large historical datasets.

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Sensor readings are an OLAP workload; daily summaries are an OLTP workload.

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Sensor readings are a NoSQL workload; daily summaries are a relational workload.

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Sensor readings are a batch workload; daily summaries are a real-time workload.

Question 11

A company stores customer orders in a database. Each order has an OrderID (integer), CustomerName (text), OrderDate (date), and a JSON column for order details that contains varying fields such as discount codes or gift messages. Which statement best describes the data types in this table?

Accepted Answer

The table stores both structured and semi-structured data.. The table includes structured columns (OrderID integer, CustomerName text, OrderDate date) and a JSON column for order details, which stores semi-structured data because JSON allows flexible schemas with varying fields like discount codes or gift messages. This combination of fixed-schema columns and a schema-less JSON column means the table holds both structured and semi-structured data, making option B correct.

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The table stores only structured data.

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The table stores only unstructured data.

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The table stores only semi-structured data.

Question 12

A bank's online transaction processing system records every withdrawal and deposit in a database. The bank also runs a monthly report that summarizes total transactions per customer. Which statement correctly identifies these two workloads?

Accepted Answer

The transaction recording is OLTP, and the monthly report is OLAP.. The transaction recording system is an OLTP (Online Transaction Processing) workload because it handles individual, real-time transactions (withdrawals and deposits) with high concurrency and low latency. The monthly report summarizing total transactions per customer is an OLAP (Online Analytical Processing) workload because it aggregates historical data for reporting and analysis, typically using batch processing or columnar storage. Option B correctly pairs each workload with its appropriate processing type.

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Both workloads are OLTP.

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The transaction recording is OLAP, and the monthly report is OLTP.

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Both workloads are OLAP.

Question 13

A company stores customer orders in a relational database that handles many small transactions (inserts, updates, deletes) throughout the day. Separately, they maintain a data warehouse that is used for complex aggregations and historical trend analysis. Which statement correctly describes these two workloads?

Accepted Answer

The first system is an OLTP workload; the second is an OLAP workload.. The first system handles many small, concurrent transactions (inserts, updates, deletes) typical of an Online Transaction Processing (OLTP) workload, optimized for ACID compliance and fast query response. The second system is an Online Analytical Processing (OLAP) workload, designed for complex aggregations and historical trend analysis using columnar storage and star schemas. This distinction is fundamental in data architecture, where OLTP systems prioritize write performance and OLAP systems prioritize read performance for large-scale analytics.

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Both systems are OLTP workloads because they store customer orders.

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The first system is an OLAP workload; the second is an OLTP workload.

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Both systems are OLAP workloads because they both involve data storage.

Question 14

A data scientist needs to analyze historical sales data to identify yearly trends. They run SQL queries that aggregate millions of rows. No new data is being added during analysis. Which type of data processing workload does this represent?

Accepted Answer

Online Analytical Processing (OLAP). This workload is Online Analytical Processing (OLAP) because the data scientist is running complex SQL queries that aggregate millions of rows of historical sales data to identify yearly trends. OLAP is designed for read-intensive, analytical queries that summarize large volumes of static data, which matches the scenario where no new data is being added during analysis.

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Online Transaction Processing (OLTP)

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Batch processing

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Stream processing

Question 15

A company stores customer information in a table with columns CustomerID, Name, Address, and PhoneNumber. Every row has values for all these columns, and the data follows a fixed schema. Which type of data does this represent?

Accepted Answer

Structured data. Structured data conforms to a fixed schema where each row has the same columns and data types. The table with CustomerID, Name, Address, and PhoneNumber, where every row contains values for all columns, perfectly fits this definition. This is typical of relational database tables (e.g., in Azure SQL Database) where the schema is enforced at the table level.

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Unstructured data

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Semi-structured data

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Streaming data