> For the complete documentation index, see [llms.txt](https://8olidity.gitbook.io/qu-kuai-lian-bi-ji/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://8olidity.gitbook.io/qu-kuai-lian-bi-ji/ji-ben-zhi-shi/openzeppelin-sheng-ji-ti-yan.md).

# openzeppelin升级体验

### 创建项目

```
npm install -g @openzeppelin/cli
oz --version
mkdir hello-oz  
cd hello-oz
npm init -y
oz init
npm install @openzeppelin/upgrades --save
```

### 部署

在contracts文件夹中创建HelloOz.sol文件

```
// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.6.0;
import "@openzeppelin/upgrades/contracts/Initializable.sol";


contract HelloOz is Initializable {
    string public name;
    uint256 public dec;
    uint256 public inc;

    function initialize(string memory _name) initializer public {
        name = _name;
    }

    function decrement(uint256 x) public returns (uint256) {
        return dec = x - 1;
    }

    function increment(uint256 x) public returns (uint256) {
        return inc = x + 1;
    }
}
```

编译合约

```
oz compile
```

部署合约上链

```
oz create
```

这里根据networks.js随便跑一个节点，这里用hardhat代替

![](/files/ui0qr1ul79WEyICDkmHp)

部署完之后可以在`.openzeppelin/dev-.json`中看到部署的信息。其中implementation就是逻辑合约的地址。<br>

![](/files/k9P6HUwrNXdNm3yO48hp)

这里模拟溢出做演示。\
首先使用

```
oz send-tx
```

设置x为0，并计算。然后

```
oz call
```

查看计算结果<br>

![](/files/rLyUy1RNTbJb1UvWW0LT)

可以看到，0-1结果溢出了。然后我们来升级合约。

### 升级

安装一个库

```
oz link @openzeppelin/contracts-ethereum-package
```

修改代码如下

```
// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.6.0;
import "@openzeppelin/upgrades/contracts/Initializable.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/math/SafeMath.sol";
contract HelloOz is Initializable {
    string public name;
    uint256 public dec;
    uint256 public inc;
    using SafeMath for uint256;
    function initialize(string memory _name) initializer public {
        name = _name;
    }
    function decrement(uint256 x) public returns (uint256) {
            return dec = x.sub(1);
        }
    function increment(uint256 x) public returns (uint256) {
            return dec = x.add(1);
        }
}
```

使用

```
oz upgrade
```

进行更新

![](/files/8E7QhCr0kH73PapEDw56)

提示我们`0xa85233C63b9Ee964Add6F2cffe00Fd84eb32338f`已经更新。再用刚才的例子测试

![](/files/4ZOPSXPTRkO1WDa4ad2C)

发现它提示溢出了。可以看到，合约地址不变。但是逻辑已经更新。

参考:\
[How to create an upgradeable smart contract using OpenZeppelin SDK | by Paulina Błaszkiewicz | Coinmonks | Medium](https://medium.com/coinmonks/how-to-create-an-upgradeable-smart-contract-using-openzeppelin-sdk-example-of-fixing-smart-260dfbfd5bae)


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