Blockchain 3 - The difference between database and blockchain

1. Database basics

1. Database definition and purpose

Please click on the link to view the article to learn about the following two points:
Database 1—Database Basics·Database Overview and Basic Concepts

• 1. Basic concepts of database
• 2. The role and importance of databases in applications

2. Overview of database management system (DBMS)

Please click link 1 to view the article to understand point 1:
Database 1—Database Basics·Database Overview and Basic Concepts

Please click link 2 to view the article to understand point 2. Link 2.1 is for learning supplement:
Database 2—Database Basics·Relational Database and SQL
Database 2.1—Knowledge Supplement of Relational Database and SQL—Fine Edition

• 1. Roles and functions of DBMS
• 2. Introduction to common database management systems (such as MySQL, PostgreSQL, Oracle)

3. Relational databases and non-relational databases

Please click link 2 to view the article to understand point 1. Link 2.1 is for supplementary learning:
Database 2—Database Basics·Relational Database and SQL
Database 2.1—Knowledge Supplement of Relational Database and SQL—Refined Edition

Please click link 7 to view the article to understand point 2:
Database 7—Non-relational database

• 1. Characteristics and applicable scenarios of relational databases
• 2. Classification and comparison of advantages and disadvantages of non-relational databases (NoSQL)

2. Blockchain Basics

Please click link 7 to view the article to understand points a, b, and c: (Among them, the comparison between the decentralization of blockchain and centralized databases will be explained later)
Blockchain 1 - Basic Concepts of Blockchain

a. Blockchain definition and uses

• Basic concepts of blockchain
• Applications of blockchain in various industries

b. Core principles of blockchain

• Concept analysis of block, chain and decentralization
• Consensus algorithm and distributed accounting

c. Decentralization characteristics of blockchain

• Comparison between blockchain decentralization and centralized databases
• Advantages and limitations of blockchain

3. Data storage method

1. Database data storage method

1.1 Storage methods of tables, indexes and views

• Table: The basic storage unit in the database, organized in the form of rows and columns. The table's data is stored on disk and can be retrieved via a query language.

• Index: used to speed up retrieval of data in the database. An index is a data structure, similar to a book's table of contents, that helps locate data quickly.

• View: Virtual table is a visual display of the query results of a table or other views. The view itself does not store data, but is generated dynamically.

1.2 Physical storage structure of database

• Data file: A file containing actual data, in the form of a table.

• Log file: records changes to the database so that it can be recovered in the event of a system crash.

• Index file: A file that stores index data to speed up data retrieval.

2. Distributed ledger storage of blockchain

2.1 How data is organized in the blockchain

• Block: Data is stored in blocks, and each block contains a certain number of transaction records.

• Chain structure: Blocks are linked through hashes to form a chain structure, ensuring the non-tamperability of data.

• Decentralized storage: Data is distributed across nodes throughout the network, rather than being stored centrally on a single server.

2.2 Security and reliability of distributed ledger

• Consensus algorithm: The blockchain uses a consensus algorithm to ensure that nodes on the distributed network agree on the status of the ledger.

• Encryption technology: Data is stored in the blockchain using encryption technology to improve security.

• Decentralized reliability: Since data is stored on multiple nodes, the system is more attack-resistant and fault-tolerant.

3. Differences and connections

• connect:

  • Databases and blockchain are both technologies used to store and manage data.
  • Both have data organization and retrieval capabilities.

• the difference:

  • Centralization vs. decentralization: Databases are centralized, while blockchains are decentralized.
  • Tamperability: Blockchain ensures the immutability of data through hashing and consensus mechanisms, while databases may be more vulnerable to single points of failure or attacks.
  • Real-time: Databases are usually more suitable for scenarios that require real-time updates and queries, while blockchain data updates may take a certain amount of time.

4. Data consistency and transaction processing

1. ACID attributes (database)

1.1 ACID attribute explanation

• Atomicity: All operations in a transaction either succeed or fail. A transaction is the smallest indivisible unit of work.

• Consistency: After a transaction is executed, the database changes from one consistency state to another. The results of transaction execution must comply with defined database rules.

• Isolation: When multiple transactions are executed concurrently, the execution of each transaction is not interfered by other transactions. Each transaction feels like the only user of the system.

• Durability: Once a transaction is committed, its results are permanent and can be recovered even if the system fails.

1.2 Concept and characteristics of transactions

• Transaction: It is a series of database operations, either all executed or all rolled back. Transactions have the characteristics of atomicity, consistency, isolation, and durability.
• characteristic:
  • 1. Atomicity: Atomicity means that all operations in a transaction either execute successfully or are rolled back if they fail. This is an "indivisible" property, meaning that all operations in a transaction either succeed together or fail together. If an error occurs during transaction execution, the system will automatically undo all executed operations and the database will be rolled back to the state before the transaction started.
  • 2. Consistency: Consistency requires transactions to transform the database from one consistency state to another. The database must maintain consistency before a transaction begins and after it ends. This means that the results of transaction execution must satisfy the integrity constraints of the database, such as uniqueness constraints, foreign key constraints, etc.
  • 3. Isolation: Isolation means that multiple transactions can be executed concurrently without interfering with each other. Each transaction is isolated from the operations of other transactions. Transaction isolation is achieved through a concurrency control mechanism to prevent data contention and conflicts between multiple transactions, thereby ensuring database consistency.
  • 4. Durability: Durability requires that once a transaction is committed, its modifications to the database are permanent and will not be lost even if the system fails. Database systems achieve durability by persistently writing transaction modifications to disk. Even after a system crash or reboot, the database should be able to recover to the state it was in after the transaction was committed.

2. Consistency mechanism of blockchain

2.1 The impact of consensus algorithm on consistency

• Consensus Algorithm: The nodes in the blockchain reach agreement through the consensus algorithm. For example, Proof of Work (PoW) and Proof of Stake (PoS) are common consensus algorithms.

• Consistency: The consensus algorithm ensures that all nodes in the network agree on the state of the blockchain to prevent problems such as double spending.

Explanation of the double-spend problem:
The double-spend problem refers to the situation where the same asset is spent multiple times in digital currency or cryptocurrency transactions. In a traditional centralized system, there is a central authority that maintains account balances and processes transactions, so the double-spending problem is less likely to occur because the centralized authority is able to prevent double spending. But in distributed systems and decentralized blockchains, there is no central organization, so consensus algorithms are needed to solve the double-spending problem.

The consensus algorithm ensures that nodes in the network agree on the validity of a transaction to prevent an account from sending the same asset to different nodes at the same time. Through the consensus algorithm, nodes in the network can reach a consistent order of transaction records, thus avoiding the occurrence of double-spending problems. This means that all nodes agree on a specific sequence of transactions, and only verified transactions are added to the blockchain, ensuring a unique, immutable transaction history.

2.2 Transaction processing methods in blockchain

• Blockchain Transactions: Transactions in the blockchain are performed by packaging multiple operations into a block. This block is added to the chain after consensus.

• Decentralized features: The decentralized features of blockchain enable transactions to be propagated and verified throughout the network, ensuring security and reliability.

3. Differences and connections

• connect:

  • Both the ACID properties and the blockchain’s consensus algorithm strive to maintain the consistency of the system.
  • The transaction concept exists in both, and both emphasize the atomicity of data changes.

• the difference:

  • Centralization vs. decentralization: Databases are usually centralized and managed by a central server. The blockchain is decentralized and has no central control agency.
  • Consensus mechanism: Databases rely on trust centers and complex permission management, while blockchains use consensus algorithms to reach consensus without the need for a central authority.
  • Privacy and Transparency: Blockchain offers greater transparency, but may sacrifice some privacy.

5. Data access control and privacy

1. Database permission management

1.1 Management of user rights and role rights

• User permissions: The database is managed through user accounts, and each user is assigned specific permissions, such as the permission to read, write, modify or delete data. Users can be individuals or applications.

• Role permissions: To simplify permission management, databases usually support the concept of roles. Administrators can assign permissions to roles and then grant roles to users. This makes it easier to manage large numbers of users.

1.2 Data encryption and access control

• Data encryption: Databases can use encryption technology to protect the privacy of data. This includes encrypted storage of data as well as encryption during transmission.

• Access control: Database systems usually provide fine-grained access control by setting access rules and policies to ensure that only authorized users can access sensitive data.

2. Decentralized identity verification on blockchain

2.1 Public and private key system and identity verification

• Public key and private key system: Users in the blockchain use public and private keys for identity verification. The public key is used for public sharing, and the private key serves as the user's private identity.

• Authentication: Users prove their identity by providing a signature that matches their private key to conduct transactions or access data on the blockchain.

2.2 Permission control mechanism in blockchain

• Smart contracts: Smart contracts in the blockchain are self-executing contracts with programmed logic. Through smart contracts, access control rules can be defined and enforced, such as restricting a user's access to specific data.

• Decentralized identity: Blockchain can support decentralized identity verification, eliminating the need for centralized identity management. Users have full control over their identity information without relying on a central authority.

3. Differences and connections

• connect:

  • Both databases and blockchain work to ensure that only authorized users have access to sensitive data.
  • Both use encryption technology to protect the privacy of data.

• the difference:

  • Centralization vs. decentralization: Databases often rely on centralized identity management, while blockchain supports decentralized identity verification.
  • Smart contracts: Blockchain achieves more flexible permission control through smart contracts, while databases usually use static permission allocation.
  • Identity management: Blockchain users have greater control and can better manage their identity information, while database users are usually subject to central management.

6. Data Security and Encryption

1. Database encryption technology

1.1 Encryption methods for data transmission and storage

• Data transmission encryption: Databases usually use encryption protocols such as SSL/TLS to encrypt data transmission between the client and the server to ensure that the data is not stolen or tampered with during transmission.

• Data storage encryption: The database can use encryption algorithms to encrypt and store data, ensuring that even if the database is illegally accessed, the data will not be easily leaked.

1.2 Practical applications of database encryption

• Field-level encryption: Encrypt sensitive data fields, such as users’ personal identity information, bank account numbers, etc.

• Transparent Data Encryption (TDE): An encryption method provided by the database system, which encrypts the entire database and is transparent to the application.

2. Blockchain encryption and hashing algorithms

2.1 Application of hash algorithm in blockchain

• Data integrity: Blockchain uses a hash algorithm to ensure data integrity. Each block contains the hash value of the previous block. Any data tampering will cause the hash value to change and be detected.

• Merkle tree: used to quickly verify the integrity of large amounts of data, especially in blockchains to verify the validity of transactions.

2.2 Digital signature and encryption guarantee in blockchain

• Digital signature: Transactions in the blockchain are authenticated through digital signatures to ensure the authenticity and integrity of the transaction.

• Asymmetric encryption: Users in the blockchain use public and private keys for encryption and decryption, ensuring the security of data transmission and transactions.

3. Differences and connections

• connect:

  • Both databases and blockchain use encryption technology to ensure the security of data, including encryption of data transmission and storage.
  • Both use hashing algorithms to ensure data integrity.

• the difference:

  • Centralization vs. decentralization: Databases often rely on centralized authentication and access control, while blockchain supports decentralized authentication and transaction confirmation.
  • Smart contracts: Blockchain uses smart contracts to achieve more flexible encryption guarantees and permission control, while databases usually use static permission allocation.

7. Data scalability and performance

1. Vertical and horizontal expansion of database

1.1 The concept of vertical expansion and horizontal expansion

• Vertical scaling: Improve database performance by increasing the processing power of a single server, such as increasing CPU, memory, or storage capacity.

• Horizontal scaling: Improve database performance by increasing the number of servers, such as through database sharding or replication to share the load.

1.2 Database performance optimization strategy

• Index optimization: Speed ​​up data retrieval through proper design and use of indexes.

• Query optimization: Improve query performance by optimizing query statements, using appropriate connection methods and conditional filtering.

• Cache optimization: Use caching technology to reduce the number of database accesses and increase data access speed.

2. Blockchain performance bottlenecks and solutions

2.1 Blockchain performance challenges and response strategies

• Transaction throughput: The transaction throughput of the blockchain may be limited. Solutions include optimizing the consensus algorithm, increasing network bandwidth, and optimizing the transaction structure.

• Storage capacity: The amount of data in blockchain can grow rapidly, and solutions include data compression, sharded storage, and storage optimization.

• Delay problem: Blockchain transaction confirmation may take a certain amount of time. Solutions include optimizing the consensus algorithm and introducing a second-layer expansion solution.

2.2 Application of layered architecture and side chain

• Layered architecture: Overall scalability and performance can be improved by dividing the blockchain network into different layers, such as using second-layer solutions such as the Lightning Network.

• Sidechain: A sidechain is a blockchain that is interconnected with the main blockchain and can be used to process specific types of transactions, reducing the burden on the main chain.

3. Differences and connections

• connect:

  • Both databases and blockchains face performance and scalability challenges that need to be solved through technical means.

• the difference:

  • Data model: Databases are usually oriented towards structured data, while blockchain is more suitable for the storage and management of distributed ledgers.
  • Consensus mechanism: The performance challenges of blockchain mainly stem from the consensus mechanism, while the performance challenges of databases mainly stem from data access and processing.

8. Smart contracts and business logic

1. Stored procedures and triggers in the database

1.1 Definition and use of stored procedures and triggers

Stored procedure:
A stored procedure is a set of precompiled SQL statements, similar to a function, that is stored in the database. Through stored procedures, a series of SQL statements can be encapsulated into a single execution unit, which improves the performance and security of the database.

Trigger:
A trigger is a database object related to a table that automatically executes when a specific event (such as insert, update, delete) occurs on the table. Triggers can be used to enforce business rules, data integrity, and log changes.

1.2 Business logic processing in the database

In a database, business logic processing usually involves the use of stored procedures and triggers. Through stored procedures, complex business logic can be encapsulated and the interaction between the client and the database can be simplified. Triggers are used to automatically perform operations under specific conditions to ensure data consistency and integrity.

2. Smart contracts in blockchain

For a more detailed explanation, please refer to my other blog:
Blockchain 2 - Solidity Smart Contract Development

2.1 Definition and characteristics of smart contracts

Smart Contract:
A smart contract is an automated contract executed on the blockchain that contains programming code that defines the rules and conditions of the contract. Smart contracts can automatically execute, verify and enforce contract terms without the need for intermediaries, thereby increasing the transparency and security of transactions.

Features:

• Immutability: Once deployed on the blockchain, the code of a smart contract is immutable.
• Automatic execution: Smart contracts can be executed automatically without third-party intervention.
• Transparency: The execution process and results of the contract are publicly verifiable, increasing trust.
• Decentralization: Smart contracts run on blockchain nodes and there is no central control agency.

2.2 Solidity language and smart contract development

Solidity language:
Solidity is a smart contract development language mainly used on the Ethereum platform. Its syntax is similar to JavaScript and is specifically designed for writing smart contracts. Solidity supports object-oriented programming, including inheritance, libraries and other features.

Smart contract development process:

1. Define the contract: Use Solidity language to write the code of the smart contract and define the state variables and methods of the contract.
2. Compile the contract: Use the Solidity compiler to convert the code into bytecode for execution on the blockchain.
3. Deploy the contract: Deploy the contract to the blockchain, create an instance of the contract, and obtain a unique contract address.
4. Interaction and invocation: Send messages to the contract through transactions, and call methods in the contract to perform corresponding operations.
5. Status changes: After the contract is executed, the status changes are recorded on the blockchain to ensure transparency and non-tamperability.

In smart contracts, business logic can be written as contract methods, and the role of triggers can be realized through automatic execution of the contract, ensuring decentralized execution and transparent business logic processing.

3. Differences and connections

• connect:

  • Business logic processing: Smart contracts, stored procedures and triggers are all used to process business logic. They can contain specific business rules, conditions, and actions to ensure data integrity and consistency.
  • Automatic execution: Both smart contracts and triggers can automatically execute under specific conditions, while stored procedures need to be called explicitly.
  • Data processing: All of these techniques can be used to process data, perform specific operations, or trigger specific events.

• the difference:

  • Operating environment: Smart contracts mainly run on the blockchain, while stored procedures and triggers mainly run in relational databases.
  • Immutability: Smart contracts are immutable once deployed on the blockchain, while stored procedures and triggers can be modified in the database.
  • Decentralization: Smart contracts are executed on a decentralized blockchain network, while stored procedures and triggers are executed on a centralized database server.
  • Programming language: Smart contracts typically use a specific smart contract programming language (such as Solidity), while stored procedures and triggers use SQL or a database-specific programming language.
  • Security: The security of smart contracts is protected by the blockchain, while the security of stored procedures and triggers depends on the security of the database.

In general, smart contracts are more suitable for decentralized scenarios that require a high degree of security and transparency, while stored procedures and triggers are more suitable for business logic processing in traditional centralized database systems.

In some cases, smart contracts and stored procedures/triggers can be used together to achieve more complex business logic processing and data interaction.