15 real Realtime Database questions from the Firebase bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.
1. What is JSON tree?
Junior
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
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
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
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
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"?
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
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