March 2022
Intermediate to advanced
293 pages
5h 31m
Chinese
Content preview from 精通区块链
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128 ｜ 第 5 章
CryptoKitties#1270015
的属性信息不是从一个集中的数据库中读取，而
是从
CryptoKittiesERC-721
智能合约中提取出来。转到函数
#32
，输入
CryptoKittiesID
，即
1270015
。从那里可以看到存储在以太坊区块链上的这个
CryptoKitties
的独一无二的属性，如图
5-2
所示。
图
5
-
2
：从 CryptoKitties 主智能合约中调用读取函数 getKitty，会响应存储在以太坊中关于
特定 kitty ID 为
1270015
的数据
5.2.3 ERC-777
这个拟议的标准是针对下一代同质化（
ERC-20
）代币。它包括对
ERC-20
标
准的一些改进，其中最重要的是代币的转移方式。
有两种方式可以让用户将
ERC-20
代币从一个地址转移到另一个地址：
推送交易（
push transaction
）
调用函数
transfer(address _to, uint256 _value)
是一个推送交易，发
送者发起了代币的转移。
拉取交易（
pull transaction
）
函数
approval(address _spender, uint256_value)
和
transferFrom
万物皆可代币化 ｜ 129
(address _from, address ...
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