C# 使用Dapper与金仓数据库交互的实现步骤_Asp.net

c# 配合 dapper 与金仓数据库（kingbasees）进行交互，可以使用如下方法实现

1. 安装必要的 nuget 包

install-package dapper
install-package npgsql  # 金仓数据库兼容 postgresql 协议

2. 基本配置和连接

using system.data;
using dapper;
using npgsql;

// 连接字符串配置
string connectionstring = "host=localhost;port=54321;database=mykingbase;user id=myuser;password=mypassword;";

// 创建连接
using (idbconnection connection = new npgsqlconnection(connectionstring))
{
    connection.open();
    
    // 执行查询
    var result = connection.query<string>("select version()");
    console.writeline(result.first());
}

3. 完整的 crud 操作示例

public class user
{
    public int id { get; set; }
    public string name { get; set; }
    public string email { get; set; }
    public datetime createdat { get; set; }
}

public class userrepository
{
    private readonly string _connectionstring;

    public userrepository(string connectionstring)
    {
        _connectionstring = connectionstring;
    }

    // 查询
    public async task<user> getuserbyidasync(int id)
    {
        using var connection = new npgsqlconnection(_connectionstring);
        return await connection.queryfirstordefaultasync<user>(
            "select * from users where id = @id", new { id = id });
    }

    // 插入
    public async task<int> insertuserasync(user user)
    {
        using var connection = new npgsqlconnection(_connectionstring);
        var sql = @"insert into users (name, email, created_at) 
                   values (@name, @email, @createdat) returning id";
        return await connection.executescalarasync<int>(sql, user);
    }

    // 更新
    public async task<int> updateuserasync(user user)
    {
        using var connection = new npgsqlconnection(_connectionstring);
        var sql = @"update users set name = @name, email = @email 
                   where id = @id";
        return await connection.executeasync(sql, user);
    }

    // 删除
    public async task<int> deleteuserasync(int id)
    {
        using var connection = new npgsqlconnection(_connectionstring);
        return await connection.executeasync(
            "delete from users where id = @id", new { id = id });
    }
}

4. 事务处理

public async task<bool> transferbalanceasync(int fromuserid, int touserid, decimal amount)
{
    using var connection = new npgsqlconnection(_connectionstring);
    connection.open();
    
    using var transaction = connection.begintransaction();
    try
    {
        // 扣款
        await connection.executeasync(
            "update accounts set balance = balance - @amount where user_id = @userid",
            new { amount = amount, userid = fromuserid }, transaction);

        // 存款
        await connection.executeasync(
            "update accounts set balance = balance + @amount where user_id = @userid",
            new { amount = amount, userid = touserid }, transaction);

        transaction.commit();
        return true;
    }
    catch
    {
        transaction.rollback();
        throw;
    }
}

5. 连接字符串配置建议

在 appsettings.json 中配置：

{
  "connectionstrings": {
    "kingbaseconnection": "host=localhost;port=54321;database=mydb;user id=myuser;password=mypassword;pooling=true;minimum pool size=5;maximum pool size=100;"
  }
}