Indexed parameters in Blockchain / Solidity - Cheat Sheet & Quick Revision

Recall & Review

beginner

What are indexed parameters in blockchain event logs?

Indexed parameters are special event parameters that are stored in the blockchain's log topics, allowing efficient filtering and searching of events by these parameters.

beginner

How many parameters can be indexed in a single event in Ethereum?

Up to three parameters can be indexed in a single event in Ethereum smart contracts.

beginner

Why use indexed parameters in blockchain events?

Indexed parameters make it easier and faster to search for specific events by filtering logs based on these parameters without scanning all event data.

intermediate

Show an example of an event declaration with indexed parameters in Solidity.

event Transfer(address indexed from, address indexed to, uint256 value);

intermediate

What is the difference between indexed and non-indexed parameters in blockchain events?

Indexed parameters are stored in topics and can be filtered efficiently, while non-indexed parameters are stored in the event data and require full log scanning to access.

How many parameters can you mark as indexed in an Ethereum event?

A 1

B 3

C 5

D Unlimited

Ethereum allows up to three parameters to be indexed in an event for efficient filtering.

What is the main benefit of using indexed parameters in blockchain events?

A Increased contract storage

B Lower gas cost for transactions

C Automatic event execution

D Faster event filtering

Indexed parameters allow faster filtering of events by storing key data in topics.

In Solidity, how do you mark a parameter as indexed in an event?

A Add the keyword 'indexed' after the parameter type

B Add the keyword 'filter' after the parameter

C Use a special event type

D Indexed parameters are not supported

You add the keyword 'indexed' after the parameter type to mark it as indexed.

Which part of the event log stores indexed parameters?

A Topics

B Data

C Transaction input

D Block header

Indexed parameters are stored in the topics section of the event log.

Can non-indexed parameters be used to filter events efficiently?

A Only if the event is small

B Yes, all parameters can be filtered equally

C No, only indexed parameters can be filtered efficiently

D Only if the blockchain is private

Only indexed parameters are stored in topics and can be filtered efficiently.

Explain what indexed parameters are and why they are useful in blockchain event logs.

Think about how events are searched on the blockchain.

Describe how to declare an event with indexed parameters in Solidity and what happens when the event is emitted.

Recall Solidity syntax and event log structure.