C# 使用Dapper与金仓数据库交互的实现步骤

Install-Package Dapper
Install-Package Npgsql  # 金仓数据库兼容 PostgreSQL 协议

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());
}

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 });
    }
}

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;
    }
}

{
  "ConnectionStrings": {
    "KingbaseConnection": "Host=localhost;Port=54321;Database=mydb;User Id=myuser;Password=mypassword;Pooling=true;Minimum Pool Size=5;Maximum Pool Size=100;"
  }
}