15 Realtime Database questions from the Firebase bank, written for Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd.
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A.the SDK feature that caches the active data set on device so reads and writes keep working without a connection
B.the inability to filter on multiple properties at once, since this store sorts and filters by only one child key per query
C.the single large hierarchical structure that this older Firebase store keeps all data in, addressed by path
D.preferring the JSON-tree store for very low-latency presence and simple state, while the newer document store wins on rich queries and scale
Answer + AI explanation with Pro
2. Which term means: "the single large hierarchical structure that this older Firebase store keeps all data in, addressed by path"?
Junior
A.Fan-out write
B.Shallow query limitation
C.Offline persistence
D.JSON tree
Answer + AI explanation with Pro
3. Which statement is correct?
Junior
A.JSON tree — preferring the JSON-tree store for very low-latency presence and simple state, while the newer document store wins on rich queries and scale
B.JSON tree — the single large hierarchical structure that this older Firebase store keeps all data in, addressed by path
C.JSON tree — the SDK feature that caches the active data set on device so reads and writes keep working without a connection
D.JSON tree — the inability to filter on multiple properties at once, since this store sorts and filters by only one child key per query
Answer + AI explanation with Pro
4. What is Shallow query limitation?
Mid
A.the single large hierarchical structure that this older Firebase store keeps all data in, addressed by path
B.the inability to filter on multiple properties at once, since this store sorts and filters by only one child key per query
C.the denormalization pattern of writing the same value to several paths at once to keep a flat structure queryable
D.the SDK feature that caches the active data set on device so reads and writes keep working without a connection
Answer + AI explanation with Pro
5. Which term means: "the inability to filter on multiple properties at once, since this store sorts and filters by only one child key per query"?
Mid
A.Choice versus Firestore
B.Shallow query limitation
C.JSON tree
D.Fan-out write
Answer + AI explanation with Pro
6. Which statement is correct?
Mid
A.Shallow query limitation — the SDK feature that caches the active data set on device so reads and writes keep working without a connection
B.Shallow query limitation — the inability to filter on multiple properties at once, since this store sorts and filters by only one child key per query
C.Shallow query limitation — the denormalization pattern of writing the same value to several paths at once to keep a flat structure queryable
D.Shallow query limitation — preferring the JSON-tree store for very low-latency presence and simple state, while the newer document store wins on rich queries and scale
Answer + AI explanation with Pro
7. What is Offline persistence?
Mid
A.the SDK feature that caches the active data set on device so reads and writes keep working without a connection
B.the denormalization pattern of writing the same value to several paths at once to keep a flat structure queryable
C.preferring the JSON-tree store for very low-latency presence and simple state, while the newer document store wins on rich queries and scale
D.the single large hierarchical structure that this older Firebase store keeps all data in, addressed by path
Answer + AI explanation with Pro
8. Which term means: "the SDK feature that caches the active data set on device so reads and writes keep working without a connection"?
Mid
A.Offline persistence
B.Fan-out write
C.JSON tree
D.Choice versus Firestore
Answer + AI explanation with Pro
9. Which statement is correct?
Mid
A.Offline persistence — the denormalization pattern of writing the same value to several paths at once to keep a flat structure queryable
B.Offline persistence — the SDK feature that caches the active data set on device so reads and writes keep working without a connection
C.Offline persistence — the inability to filter on multiple properties at once, since this store sorts and filters by only one child key per query
D.Offline persistence — the single large hierarchical structure that this older Firebase store keeps all data in, addressed by path
Answer + AI explanation with Pro
10. What is Fan-out write?
Senior
A.the inability to filter on multiple properties at once, since this store sorts and filters by only one child key per query
B.the SDK feature that caches the active data set on device so reads and writes keep working without a connection
C.the single large hierarchical structure that this older Firebase store keeps all data in, addressed by path
D.the denormalization pattern of writing the same value to several paths at once to keep a flat structure queryable
Answer + AI explanation with Pro
11. Which term means: "the denormalization pattern of writing the same value to several paths at once to keep a flat structure queryable"?
Senior
A.JSON tree
B.Offline persistence
C.Fan-out write
D.Shallow query limitation
Answer + AI explanation with Pro
12. Which statement is correct?
Senior
A.Fan-out write — preferring the JSON-tree store for very low-latency presence and simple state, while the newer document store wins on rich queries and scale
B.Fan-out write — the single large hierarchical structure that this older Firebase store keeps all data in, addressed by path
C.Fan-out write — the denormalization pattern of writing the same value to several paths at once to keep a flat structure queryable
D.Fan-out write — the inability to filter on multiple properties at once, since this store sorts and filters by only one child key per query
Answer + AI explanation with Pro
13. What is Choice versus Firestore?
Senior
A.preferring the JSON-tree store for very low-latency presence and simple state, while the newer document store wins on rich queries and scale
B.the inability to filter on multiple properties at once, since this store sorts and filters by only one child key per query
C.the single large hierarchical structure that this older Firebase store keeps all data in, addressed by path
D.the SDK feature that caches the active data set on device so reads and writes keep working without a connection
Answer + AI explanation with Pro
14. Which term means: "preferring the JSON-tree store for very low-latency presence and simple state, while the newer document store wins on rich queries and scale"?
Senior
A.Fan-out write
B.Choice versus Firestore
C.Shallow query limitation
D.Offline persistence
Answer + AI explanation with Pro
15. Which statement is correct?
Senior
A.Choice versus Firestore — the single large hierarchical structure that this older Firebase store keeps all data in, addressed by path
B.Choice versus Firestore — the inability to filter on multiple properties at once, since this store sorts and filters by only one child key per query
C.Choice versus Firestore — preferring the JSON-tree store for very low-latency presence and simple state, while the newer document store wins on rich queries and scale
D.Choice versus Firestore — the SDK feature that caches the active data set on device so reads and writes keep working without a connection
Answer + AI explanation with Pro
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