C# MySQL 实现多层级联数据迁移

Dictionary<int, int> parentIdMapping = new Dictionary<int, int>();

using (var sourceConn = new MySqlConnection(sourceConnectionString))
using (var targetConn = new MySqlConnection(targetConnectionString))
{
    sourceConn.Open();
    targetConn.Open();
    
    // 迁移父表数据
    using (var transaction = targetConn.BeginTransaction())
    {
        try
        {
            // 示例：迁移用户表
            var cmdSelect = new MySqlCommand("SELECT id, name FROM users", sourceConn);
            using (var reader = cmdSelect.ExecuteReader())
            {
                while (reader.Read())
                {
                    var insertCmd = new MySqlCommand(
                        "INSERT INTO users (name) VALUES (@name); SELECT LAST_INSERT_ID();",
                        targetConn, transaction);
                    
                    insertCmd.Parameters.AddWithValue("@name", reader["name"]);
                    var newId = Convert.ToInt32(insertCmd.ExecuteScalar());
                    
                    parentIdMapping.Add(reader.GetInt32(0), newId);
                }
            }
            
            // 迁移子表（示例：订单表）
            MigrateChildTable("orders", "user_id", parentIdMapping, sourceConn, targetConn, transaction);
            
            transaction.Commit();
        }
        catch
        {
            transaction.Rollback();
            throw;
        }
    }
}

void MigrateChildTable(string tableName, string fkColumn, 
    Dictionary<int, int> idMapping, 
    MySqlConnection sourceConn, MySqlConnection targetConn,
    MySqlTransaction transaction)
{
    var cmd = new MySqlCommand($"SELECT * FROM {tableName}", sourceConn);
    using (var reader = cmd.ExecuteReader())
    {
        while (reader.Read())
        {
            var insertCmd = new MySqlCommand(
                $"INSERT INTO {tableName} ({fkColumn}, ...) VALUES (@newFk, ...)",
                targetConn, transaction);
            
            // 转换外键值
            var oldFk = reader.GetInt32(fkColumn);
            insertCmd.Parameters.AddWithValue("@newFk", idMapping[oldFk]);
            
            // 添加其他参数...
            insertCmd.ExecuteNonQuery();
        }
    }
}

ALTER TABLE target_table AUTO_INCREMENT = {new_value};

SET FOREIGN_KEY_CHECKS = 0;

SET FOREIGN_KEY_CHECKS = 1;

graph TD
    A[部门表] --> B[员工表]
    B --> C[项目表]
    C --> D[任务表]

// 验证记录数
var sourceCount = ExecuteScalar("SELECT COUNT(*) FROM source_table");
var targetCount = ExecuteScalar("SELECT COUNT(*) FROM target_table");

// 验证外键关联
var sql = @"SELECT COUNT(*) FROM child_table 
           WHERE NOT EXISTS (
               SELECT 1 FROM parent_table 
               WHERE parent_table.id = child_table.parent_id
           )";
var orphanRecords = ExecuteScalar(sql);