PDE Storing the Data Practice Question
An application needs to store user profile data in a document database with flexible schema. The data is accessed frequently from a mobile app. Which Google Cloud database is BEST suited?
⚠ Common exam trap
Test-takers frequently confuse Cloud Firestore with Cloud Bigtable because both are NoSQL, but Bigtable lacks document flexibility, real-time sync, and mobile SDK support, which are essential for the described use case.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Cloud Firestore
Cloud Firestore is a NoSQL document database designed for mobile and web app development, offering flexible schema, real-time data synchronization, and automatic scaling. It directly supports frequent reads from mobile apps through its client SDKs and offline persistence, making it the best fit for storing user profile data with varying attributes.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Cloud Bigtable
Why it's wrong here
Cloud Bigtable is a wide-column NoSQL store keyed by row, lacking document semantics and flexible nested schemas for profile fields. It is tempting because it delivers low-latency access at scale, and it is correct for high-throughput time-series or key-range workloads, not mobile document storage.
- ✗
BigQuery
Why it's wrong here
BigQuery is an analytics warehouse for SQL queries over columnar data, not low-latency document reads and writes from a mobile app. It is tempting because it stores semi-structured data cheaply, and it is correct when the workload is large-scale analytical reporting rather than transactional profile lookups.
- ✗
Cloud Spanner
Why it's wrong here
Cloud Spanner is a globally distributed, strongly consistent relational database requiring fixed schemas and horizontal scaling, so it cannot provide the flexible document schema this profile data needs. It is tempting because Spanner suits high-throughput, multi-region transactional workloads needing SQL and strong consistency, not mobile document storage.
- ✓
Cloud Firestore
Why this is correct
Cloud Firestore is a serverless document database with flexible schema and native mobile SDKs offering real-time sync and offline support. It suits frequently accessed user profile data from mobile apps, meeting the flexible-schema and mobile-access constraints.
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This PDE practice question is part of Courseiva's free Google Cloud certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PDE exam.