Indexes & Transactions interview questions

1. A.Atomicity, Consistency, Isolation, Durability — the guarantees of a reliable transaction
2. B.a structure (usually a B-tree) that speeds lookups at the cost of slower writes and extra storage
3. C.two transactions each waiting on a lock the other holds, resolved by the database aborting one
4. D.an index containing every column a query needs, avoiding a table lookup

Answer + AI explanation with Pro

1. A.Deadlock
2. B.Index
3. C.Isolation levels
4. D.Covering index

Answer + AI explanation with Pro

1. A.Index — a structure (usually a B-tree) that speeds lookups at the cost of slower writes and extra storage
2. B.Index — Read Uncommitted, Read Committed, Repeatable Read and Serializable — trading consistency for concurrency
3. C.Index — an index containing every column a query needs, avoiding a table lookup
4. D.Index — Atomicity, Consistency, Isolation, Durability — the guarantees of a reliable transaction

Answer + AI explanation with Pro

1. A.two transactions each waiting on a lock the other holds, resolved by the database aborting one
2. B.a structure (usually a B-tree) that speeds lookups at the cost of slower writes and extra storage
3. C.an index on multiple columns, usable left-to-right by the leftmost-prefix rule
4. D.Atomicity, Consistency, Isolation, Durability — the guarantees of a reliable transaction

Answer + AI explanation with Pro

1. A.Composite index
2. B.Covering index
3. C.ACID
4. D.Index

Answer + AI explanation with Pro

1. A.Composite index — an index containing every column a query needs, avoiding a table lookup
2. B.Composite index — a structure (usually a B-tree) that speeds lookups at the cost of slower writes and extra storage
3. C.Composite index — an index on multiple columns, usable left-to-right by the leftmost-prefix rule
4. D.Composite index — Atomicity, Consistency, Isolation, Durability — the guarantees of a reliable transaction

Answer + AI explanation with Pro

1. A.two transactions each waiting on a lock the other holds, resolved by the database aborting one
2. B.an index on multiple columns, usable left-to-right by the leftmost-prefix rule
3. C.an index containing every column a query needs, avoiding a table lookup
4. D.Atomicity, Consistency, Isolation, Durability — the guarantees of a reliable transaction

Answer + AI explanation with Pro

1. A.Covering index
2. B.Deadlock
3. C.Index
4. D.Composite index

Answer + AI explanation with Pro

1. A.Covering index — Read Uncommitted, Read Committed, Repeatable Read and Serializable — trading consistency for concurrency
2. B.Covering index — an index on multiple columns, usable left-to-right by the leftmost-prefix rule
3. C.Covering index — an index containing every column a query needs, avoiding a table lookup
4. D.Covering index — Atomicity, Consistency, Isolation, Durability — the guarantees of a reliable transaction

Answer + AI explanation with Pro

1. A.two transactions each waiting on a lock the other holds, resolved by the database aborting one
2. B.a structure (usually a B-tree) that speeds lookups at the cost of slower writes and extra storage
3. C.Atomicity, Consistency, Isolation, Durability — the guarantees of a reliable transaction
4. D.an index on multiple columns, usable left-to-right by the leftmost-prefix rule

Answer + AI explanation with Pro

1. A.Deadlock
2. B.Isolation levels
3. C.Composite index
4. D.ACID

Answer + AI explanation with Pro

1. A.ACID — an index on multiple columns, usable left-to-right by the leftmost-prefix rule
2. B.ACID — Read Uncommitted, Read Committed, Repeatable Read and Serializable — trading consistency for concurrency
3. C.ACID — two transactions each waiting on a lock the other holds, resolved by the database aborting one
4. D.ACID — Atomicity, Consistency, Isolation, Durability — the guarantees of a reliable transaction

Answer + AI explanation with Pro

1. A.Atomicity, Consistency, Isolation, Durability — the guarantees of a reliable transaction
2. B.Read Uncommitted, Read Committed, Repeatable Read and Serializable — trading consistency for concurrency
3. C.two transactions each waiting on a lock the other holds, resolved by the database aborting one
4. D.a structure (usually a B-tree) that speeds lookups at the cost of slower writes and extra storage

Answer + AI explanation with Pro

1. A.Isolation levels
2. B.Covering index
3. C.Composite index
4. D.Deadlock

Answer + AI explanation with Pro

1. A.Isolation levels — an index containing every column a query needs, avoiding a table lookup
2. B.Isolation levels — Atomicity, Consistency, Isolation, Durability — the guarantees of a reliable transaction
3. C.Isolation levels — Read Uncommitted, Read Committed, Repeatable Read and Serializable — trading consistency for concurrency
4. D.Isolation levels — a structure (usually a B-tree) that speeds lookups at the cost of slower writes and extra storage

Answer + AI explanation with Pro

1. A.a structure (usually a B-tree) that speeds lookups at the cost of slower writes and extra storage
2. B.two transactions each waiting on a lock the other holds, resolved by the database aborting one
3. C.an index on multiple columns, usable left-to-right by the leftmost-prefix rule
4. D.an index containing every column a query needs, avoiding a table lookup

Answer + AI explanation with Pro

1. A.Deadlock
2. B.ACID
3. C.Composite index
4. D.Covering index

Answer + AI explanation with Pro

1. A.Deadlock — Read Uncommitted, Read Committed, Repeatable Read and Serializable — trading consistency for concurrency
2. B.Deadlock — two transactions each waiting on a lock the other holds, resolved by the database aborting one
3. C.Deadlock — Atomicity, Consistency, Isolation, Durability — the guarantees of a reliable transaction
4. D.Deadlock — an index containing every column a query needs, avoiding a table lookup

Answer + AI explanation with Pro