OceanBase在.NET开发操作指南

OceanBase与.NET开发概述

OceanBase是阿里巴巴集团自主研发的分布式关系型数据库，具有高可用、高性能、高扩展等特点。在.NET环境下开发OceanBase应用，主要通过ADO.NET接口或ORM框架实现。

OceanBase特点

1. 分布式架构：支持水平扩展，数据自动分片
2. 高可用性：基于Paxos协议的多副本一致性
3. 兼容性：兼容MySQL协议，支持大部分MySQL语法
4. HTAP能力：同时支持OLTP和OLAP场景

.NET开发选择

1. ADO.NET：使用MySQL官方提供的Connector/NET
2. ORM框架：Entity Framework Core、Dapper等
3. 第三方驱动：如MySqlConnector等替代驱动

环境配置与连接管理

安装驱动

# 使用NuGet安装MySQL官方驱动
Install-Package MySql.Data

基础连接配置

using MySql.Data.MySqlClient;

string connectionString = "server=obproxy.mydomain.com;port=2883;user=root;password=yourpassword;database=test;";
using (var connection = new MySqlConnection(connectionString))
{
    try
    {
        connection.Open();
        Console.WriteLine("连接OceanBase成功！");
    }
    catch (Exception ex)
    {
        Console.WriteLine($"连接失败: {ex.Message}");
    }
}

连接池配置

string connectionString = "server=obproxy.mydomain.com;port=2883;user=root;password=yourpassword;database=test;" +
                         "Pooling=true;MinimumPoolSize=5;MaximumPoolSize=100;ConnectionTimeout=30;";

// 高级连接池配置示例
var builder = new MySqlConnectionStringBuilder(connectionString)
{
    Pooling = true,
    MinimumPoolSize = 10,
    MaximumPoolSize = 200,
    ConnectionIdleTimeout = 300,
    ConnectionLifeTime = 1800
};

多租户连接配置

OceanBase支持多租户架构，连接时需要指定租户：

string tenantConnectionString = "server=obproxy.mydomain.com;port=2883;user=user@tenant;password=password;database=test;";

基础CRUD操作

创建表

using (var connection = new MySqlConnection(connectionString))
{
    connection.Open();
    
    var createTableSql = @"
    CREATE TABLE IF NOT EXISTS employees (
        id BIGINT PRIMARY KEY,
        name VARCHAR(100) NOT NULL,
        email VARCHAR(100) UNIQUE,
        salary DECIMAL(15,2),
        hire_date DATETIME,
        department_id INT,
        INDEX idx_department (department_id),
        INDEX idx_name (name)
    ) PARTITION BY HASH(id) PARTITIONS 16;";
    
    using (var command = new MySqlCommand(createTableSql, connection))
    {
        command.ExecuteNonQuery();
        Console.WriteLine("表创建成功");
    }
}

插入数据

// 单条插入
var insertSql = "INSERT INTO employees (id, name, email, salary, hire_date, department_id) " +
                "VALUES (@id, @name, @email, @salary, @hire_date, @department_id)";

using (var command = new MySqlCommand(insertSql, connection))
{
    command.Parameters.AddWithValue("@id", 1);
    command.Parameters.AddWithValue("@name", "张三");
    command.Parameters.AddWithValue("@email", "zhangsan@example.com");
    command.Parameters.AddWithValue("@salary", 15000.50m);
    command.Parameters.AddWithValue("@hire_date", DateTime.Now);
    command.Parameters.AddWithValue("@department_id", 101);
    
    int rowsAffected = command.ExecuteNonQuery();
    Console.WriteLine($"插入了 {rowsAffected} 行数据");
}

查询数据

// 基础查询
var query = "SELECT id, name, email, salary, hire_date FROM employees WHERE department_id = @deptId";

using (var command = new MySqlCommand(query, connection))
{
    command.Parameters.AddWithValue("@deptId", 101);
    
    using (var reader = command.ExecuteReader())
    {
        while (reader.Read())
        {
            Console.WriteLine($"ID: {reader["id"]}, 姓名: {reader["name"]}, " +
                              $"邮箱: {reader["email"]}, 薪资: {reader.GetDecimal(3)}");
        }
    }
}

更新数据

var updateSql = "UPDATE employees SET salary = salary * 1.1 WHERE department_id = @deptId";

using (var command = new MySqlCommand(updateSql, connection))
{
    command.Parameters.AddWithValue("@deptId", 101);
    
    int rowsUpdated = command.ExecuteNonQuery();
    Console.WriteLine($"更新了 {rowsUpdated} 行数据");
}

删除数据

var deleteSql = "DELETE FROM employees WHERE id = @id";

using (var command = new MySqlCommand(deleteSql, connection))
{
    command.Parameters.AddWithValue("@id", 1);
    
    int rowsDeleted = command.ExecuteNonQuery();
    Console.WriteLine($"删除了 {rowsDeleted} 行数据");
}

事务处理

基础事务示例

using (var connection = new MySqlConnection(connectionString))
{
    connection.Open();
    
    using (var transaction = connection.BeginTransaction())
    {
        try
        {
            // 插入员工记录
            var insertEmp = "INSERT INTO employees (id, name, salary) VALUES (1001, '李四', 20000)";
            using (var cmd1 = new MySqlCommand(insertEmp, connection, transaction))
            {
                cmd1.ExecuteNonQuery();
            }
            
            // 更新部门预算
            var updateBudget = "UPDATE departments SET budget = budget - 20000 WHERE id = 10";
            using (var cmd2 = new MySqlCommand(updateBudget, connection, transaction))
            {
                int affected = cmd2.ExecuteNonQuery();
                if (affected == 0)
                {
                    throw new Exception("部门不存在，回滚事务");
                }
            }
            
            transaction.Commit();
            Console.WriteLine("事务提交成功");
        }
        catch (Exception ex)
        {
            transaction.Rollback();
            Console.WriteLine($"事务回滚: {ex.Message}");
        }
    }
}

分布式事务处理

OceanBase支持分布式事务，可通过XA协议实现：

// XA事务示例
using (var connection = new MySqlConnection(connectionString))
{
    connection.Open();
    
    // 开启XA事务
    using (var xaStart = new MySqlCommand("XA START 'transaction1'", connection))
    {
        xaStart.ExecuteNonQuery();
    }
    
    try
    {
        // 执行多个SQL操作
        using (var cmd1 = new MySqlCommand("INSERT INTO table1 VALUES (1, 'data1')", connection))
        {
            cmd1.ExecuteNonQuery();
        }
        
        using (var cmd2 = new MySqlCommand("UPDATE table2 SET value = 'new' WHERE id = 1", connection))
        {
            cmd2.ExecuteNonQuery();
        }
        
        // 准备阶段
        using (var xaEnd = new MySqlCommand("XA END 'transaction1'", connection))
        using (var xaPrepare = new MySqlCommand("XA PREPARE 'transaction1'", connection))
        {
            xaEnd.ExecuteNonQuery();
            xaPrepare.ExecuteNonQuery();
        }
        
        // 提交阶段
        using (var xaCommit = new MySqlCommand("XA COMMIT 'transaction1'", connection))
        {
            xaCommit.ExecuteNonQuery();
            Console.WriteLine("分布式事务提交成功");
        }
    }
    catch (Exception)
    {
        // 回滚
        using (var xaRollback = new MySqlCommand("XA ROLLBACK 'transaction1'", connection))
        {
            xaRollback.ExecuteNonQuery();
            Console.WriteLine("分布式事务回滚");
        }
        throw;
    }
}

批量操作与性能优化

批量插入

// 使用Bulk Insert提高性能
var insertSql = "INSERT INTO employees (id, name, email, salary, hire_date, department_id) " +
                "VALUES (@id, @name, @email, @salary, @hire_date, @department_id)";

using (var connection = new MySqlConnection(connectionString))
{
    connection.Open();
    
    using (var transaction = connection.BeginTransaction())
    using (var command = new MySqlCommand(insertSql, connection, transaction))
    {
        // 添加参数
        command.Parameters.Add("@id", MySqlDbType.Int64);
        command.Parameters.Add("@name", MySqlDbType.VarChar);
        command.Parameters.Add("@email", MySqlDbType.VarChar);
        command.Parameters.Add("@salary", MySqlDbType.Decimal);
        command.Parameters.Add("@hire_date", MySqlDbType.DateTime);
        command.Parameters.Add("@department_id", MySqlDbType.Int32);
        
        // 批量添加数据
        for (int i = 0; i < 1000; i++)
        {
            command.Parameters["@id"].Value = 2000 + i;
            command.Parameters["@name"].Value = $"员工_{i}";
            command.Parameters["@email"].Value = $"user_{i}@company.com";
            command.Parameters["@salary"].Value = 5000 + (i % 10) * 1000;
            command.Parameters["@hire_date"].Value = DateTime.Now.AddDays(-i);
            command.Parameters["@department_id"].Value = 100 + (i % 5);
            
            command.ExecuteNonQuery();
        }
        
        transaction.Commit();
        Console.WriteLine("批量插入完成");
    }
}

使用MySqlBulkLoader

// 创建CSV文件
File.WriteAllText("employees.csv", 
    "1,张三,zhangsan@example.com,15000.50,2023-01-15,101\n" +
    "2,李四,lisi@example.com,18000.00,2022-11-20,102");

using (var connection = new MySqlConnection(connectionString))
{
    connection.Open();
    
    var bulkLoader = new MySqlBulkLoader(connection)
    {
        TableName = "employees",
        FieldTerminator = ",",
        LineTerminator = "\n",
        FileName = "employees.csv",
        NumberOfLinesToSkip = 0,
        Columns = { "id", "name", "email", "salary", "hire_date", "department_id" }
    };
    
    int count = bulkLoader.Load();
    Console.WriteLine($"通过BulkLoader插入了 {count} 行数据");
}

批量更新

// 使用CASE WHEN实现批量更新
var updateSql = @"
UPDATE employees 
SET salary = CASE id
    WHEN @id1 THEN @salary1
    WHEN @id2 THEN @salary2
    WHEN @id3 THEN @salary3
END
WHERE id IN (@id1, @id2, @id3)";

using (var connection = new MySqlConnection(connectionString))
{
    connection.Open();
    
    using (var command = new MySqlCommand(updateSql, connection))
    {
        command.Parameters.AddWithValue("@id1", 101);
        command.Parameters.AddWithValue("@salary1", 20000);
        command.Parameters.AddWithValue("@id2", 102);
        command.Parameters.AddWithValue("@salary2", 22000);
        command.Parameters.AddWithValue("@id3", 103);
        command.Parameters.AddWithValue("@salary3", 25000);
        
        int rowsUpdated = command.ExecuteNonQuery();
        Console.WriteLine($"批量更新了 {rowsUpdated} 行数据");
    }
}

存储过程与函数调用

创建存储过程

var createProcSql = @"
CREATE PROCEDURE increase_salary(IN dept_id INT, IN increase_percent DECIMAL(5,2))
BEGIN
    UPDATE employees 
    SET salary = salary * (1 + increase_percent / 100)
    WHERE department_id = dept_id;
    
    SELECT COUNT(*) AS affected_rows FROM employees WHERE department_id = dept_id;
END";

using (var connection = new MySqlConnection(connectionString))
{
    connection.Open();
    
    using (var command = new MySqlCommand(createProcSql, connection))
    {
        command.ExecuteNonQuery();
        Console.WriteLine("存储过程创建成功");
    }
}

调用存储过程

using (var connection = new MySqlConnection(connectionString))
{
    connection.Open();
    
    using (var command = new MySqlCommand("increase_salary", connection))
    {
        command.CommandType = CommandType.StoredProcedure;
        
        command.Parameters.AddWithValue("@dept_id", 101);
        command.Parameters.AddWithValue("@increase_percent", 5.0m);
        
        using (var reader = command.ExecuteReader())
        {
            while (reader.Read())
            {
                Console.WriteLine($"影响了 {reader["affected_rows"]} 行数据");
            }
        }
    }
}

使用输出参数

var createProcWithOutput = @"
CREATE PROCEDURE get_employee_stats(IN dept_id INT, OUT avg_salary DECIMAL(15,2), OUT max_salary DECIMAL(15,2))
BEGIN
    SELECT AVG(salary), MAX(salary) INTO avg_salary, max_salary
    FROM employees WHERE department_id = dept_id;
END";

// 先创建存储过程
using (var connection = new MySqlConnection(connectionString))
{
    connection.Open();
    using (var command = new MySqlCommand(createProcWithOutput, connection))
    {
        command.ExecuteNonQuery();
    }
}

// 调用带输出参数的存储过程
using (var connection = new MySqlConnection(connectionString))
{
    connection.Open();
    
    using (var command = new MySqlCommand("get_employee_stats", connection))
    {
        command.CommandType = CommandType.StoredProcedure;
        
        command.Parameters.AddWithValue("@dept_id", 101);
        
        var avgSalaryParam = new MySqlParameter("@avg_salary", MySqlDbType.Decimal)
        {
            Direction = ParameterDirection.Output,
            Precision = 15,
            Scale = 2
        };
        command.Parameters.Add(avgSalaryParam);
        
        var maxSalaryParam = new MySqlParameter("@max_salary", MySqlDbType.Decimal)
        {
            Direction = ParameterDirection.Output,
            Precision = 15,
            Scale = 2
        };
        command.Parameters.Add(maxSalaryParam);
        
        command.ExecuteNonQuery();
        
        Console.WriteLine($"部门101的平均薪资: {avgSalaryParam.Value}, 最高薪资: {maxSalaryParam.Value}");
    }
}

数据类型映射与处理

.NET与OceanBase类型映射

.NET类型	OceanBase类型	MySqlDbType枚举
int	INT	Int32
long	BIGINT	Int64
decimal	DECIMAL	Decimal
float	FLOAT	Float
double	DOUBLE	Double
string	VARCHAR, CHAR	VarChar, String
DateTime	DATETIME	DateTime
bool	TINYINT(1)	Bool
byte[]	BLOB	Blob

特殊类型处理

JSON类型处理

// 创建包含JSON列的表
var createTableWithJson = @"
CREATE TABLE IF NOT EXISTS products (
    id BIGINT PRIMARY KEY,
    name VARCHAR(100),
    attributes JSON,
    created_at DATETIME DEFAULT CURRENT_TIMESTAMP
)";

// 插入JSON数据
var insertJson = "INSERT INTO products (id, name, attributes) VALUES (1, '智能手机', @attributes)";

using (var connection = new MySqlConnection(connectionString))
{
    connection.Open();
    
    // 创建表
    using (var cmdCreate = new MySqlCommand(createTableWithJson, connection))
    {
        cmdCreate.ExecuteNonQuery();
    }
    
    // 插入JSON数据
    using (var cmdInsert = new MySqlCommand(insertJson, connection))
    {
        var json = new {
            color = "黑色",
            memory = "128GB",
            camera = "48MP",
            features = new[] { "防水", "面部识别" }
        };
        
        cmdInsert.Parameters.AddWithValue("@attributes", JsonConvert.SerializeObject(json));
        cmdInsert.ExecuteNonQuery();
    }
    
    // 查询JSON数据
    using (var cmdQuery = new MySqlCommand("SELECT id, name, attributes->'$.color' AS color FROM products", connection))
    using (var reader = cmdQuery.ExecuteReader())
    {
        while (reader.Read())
        {
            Console.WriteLine($"产品: {reader["name"]}, 颜色: {reader["color"]}");
        }
    }
}

枚举类型处理

// 枚举处理示例
public enum EmployeeStatus { Active, OnLeave, Terminated }

var insertWithEnum = "INSERT INTO employees (id, name, status) VALUES (@id, @name, @status)";

using (var connection = new MySqlConnection(connectionString))
{
    connection.Open();
    
    using (var command = new MySqlCommand(insertWithEnum, connection))
    {
        command.Parameters.AddWithValue("@id", 1001);
        command.Parameters.AddWithValue("@name", "王五");
        command.Parameters.AddWithValue("@status", EmployeeStatus.Active.ToString());
        
        command.ExecuteNonQuery();
    }
}

高级查询技术

分页查询

// OceanBase分页查询（兼容MySQL语法）
public List<Employee> GetEmployeesPaged(int pageNumber, int pageSize, string sortColumn, bool sortAsc)
{
    var employees = new List<Employee>();
    
    using (var connection = new MySqlConnection(connectionString))
    {
        connection.Open();
        
        var offset = (pageNumber - 1) * pageSize;
        var sortDirection = sortAsc ? "ASC" : "DESC";
        
        var query = $@"
        SELECT id, name, email, salary, hire_date, department_id
        FROM employees
        ORDER BY {sortColumn} {sortDirection}
        LIMIT {pageSize} OFFSET {offset}";
        
        using (var command = new MySqlCommand(query, connection))
        using (var reader = command.ExecuteReader())
        {
            while (reader.Read())
            {
                employees.Add(new Employee
                {
                    Id = reader.GetInt64("id"),
                    Name = reader.GetString("name"),
                    Email = reader.IsDBNull("email") ? null : reader.GetString("email"),
                    Salary = reader.GetDecimal("salary"),
                    HireDate = reader.GetDateTime("hire_date"),
                    DepartmentId = reader.GetInt32("department_id")
                });
            }
        }
    }
    
    return employees;
}

窗口函数

// 使用窗口函数计算排名
var windowQuery = @"
SELECT 
    id, 
    name, 
    salary,
    department_id,
    RANK() OVER (PARTITION BY department_id ORDER BY salary DESC) AS dept_salary_rank,
    salary - LAG(salary, 1, 0) OVER (PARTITION BY department_id ORDER BY salary) AS salary_diff
FROM employees
ORDER BY department_id, salary DESC";

using (var connection = new MySqlConnection(connectionString))
{
    connection.Open();
    
    using (var command = new MySqlCommand(windowQuery, connection))
    using (var reader = command.ExecuteReader())
    {
        Console.WriteLine("ID\t姓名\t薪资\t部门\t部门排名\t薪资差");
        while (reader.Read())
        {
            Console.WriteLine($"{reader["id"]}\t{reader["name"]}\t{reader["salary"]}\t" +
                            $"{reader["department_id"]}\t{reader["dept_salary_rank"]}\t" +
                            $"{reader["salary_diff"]}");
        }
    }
}

全文检索

// 创建全文索引
var createFulltextIndex = @"
ALTER TABLE employees 
ADD FULLTEXT INDEX ft_name_email (name, email)";

// 全文检索查询
var fulltextQuery = @"
SELECT id, name, email, 
    MATCH(name, email) AGAINST(@searchTerm IN NATURAL LANGUAGE MODE) AS relevance
FROM employees
WHERE MATCH(name, email) AGAINST(@searchTerm IN NATURAL LANGUAGE MODE)
ORDER BY relevance DESC";

using (var connection = new MySqlConnection(connectionString))
{
    connection.Open();
    
    // 创建全文索引
    using (var cmdIndex = new MySqlCommand(createFulltextIndex, connection))
    {
        cmdIndex.ExecuteNonQuery();
    }
    
    // 执行全文检索
    using (var cmdSearch = new MySqlCommand(fulltextQuery, connection))
    {
        cmdSearch.Parameters.AddWithValue("@searchTerm", "张经理 OR 总监");
        
        using (var reader = cmdSearch.ExecuteReader())
        {
            while (reader.Read())
            {
                Console.WriteLine($"匹配结果: {reader["name"]} ({reader["email"]}), 相关度: {reader["relevance"]}");
            }
        }
    }
}

JSON数据处理

OceanBase支持丰富的JSON函数，可以高效处理JSON数据。

JSON查询与修改

// JSON数据查询与修改示例
var jsonOperations = @"
-- 插入JSON数据
INSERT INTO products (id, name, attributes) 
VALUES (2, '笔记本电脑', JSON_OBJECT('brand', 'Dell', 'cpu', 'i7', 'ram', '16GB'));

-- 查询JSON属性
SELECT id, name, JSON_EXTRACT(attributes, '$.brand') AS brand FROM products;

-- 修改JSON属性
UPDATE products 
SET attributes = JSON_SET(attributes, '$.ram', '32GB', '$.storage', '1TB SSD') 
WHERE id = 2;

-- 查询修改后的JSON
SELECT id, name, attributes FROM products WHERE id = 2;";

using (var connection = new MySqlConnection(connectionString))
{
    connection.Open();
    
    // 执行多条JSON操作
    using (var command = new MySqlCommand(jsonOperations, connection))
    {
        using (var reader = command.ExecuteReader())
        {
            do
            {
                while (reader.Read())
                {
                    if (reader.FieldCount == 3)
                    {
                        Console.WriteLine($"产品: {reader["name"]}, 品牌: {reader["brand"]}");
                    }
                    else if (reader.FieldCount == 2)
                    {
                        Console.WriteLine($"产品: {reader["name"]}, 完整属性: {reader["attributes"]}");
                    }
                }
            } while (reader.NextResult());
        }
    }
}

JSON数组处理

// JSON数组处理示例
var jsonArrayQuery = @"
-- 创建包含JSON数组的表
CREATE TABLE IF NOT EXISTS orders (
    id BIGINT PRIMARY KEY,
    customer_id BIGINT,
    items JSON,
    order_date DATETIME
);

-- 插入包含数组的JSON数据
INSERT INTO orders (id, customer_id, items, order_date)
VALUES (1, 1001, 
    JSON_ARRAY(
        JSON_OBJECT('product_id', 101, 'quantity', 2, 'price', 5999),
        JSON_OBJECT('product_id', 205, 'quantity', 1, 'price', 1299)
    ),
    NOW());

-- 查询JSON数组
SELECT 
    id,
    customer_id,
    JSON_LENGTH(items) AS item_count,
    JSON_EXTRACT(items, '$[0].product_id') AS first_product_id,
    JSON_SEARCH(items, 'one', 205, NULL, '$[*].product_id') AS item_path
FROM orders;";

using (var connection = new MySqlConnection(connectionString))
{
    connection.Open();
    
    using (var command = new MySqlCommand(jsonArrayQuery, connection))
    {
        using (var reader = command.ExecuteReader())
        {
            while (reader.Read())
            {
                Console.WriteLine($"订单ID: {reader["id"]}, 商品数量: {reader["item_count"]}, " +
                                $"第一个商品ID: {reader["first_product_id"]}, " +
                                $"商品205路径: {reader["item_path"]}");
            }
        }
    }
}

分布式事务处理

OceanBase作为分布式数据库，提供了强大的分布式事务支持。

跨分区事务

// 跨分区事务示例
using (var connection = new MySqlConnection(connectionString))
{
    connection.Open();
    
    using (var transaction = connection.BeginTransaction())
    {
        try
        {
            // 操作分区表1
            var updateAccount = @"
            UPDATE accounts 
            SET balance = balance - 1000 
            WHERE account_id = 'A1001'";
            
            using (var cmd1 = new MySqlCommand(updateAccount, connection, transaction))
            {
                int affected = cmd1.ExecuteNonQuery();
                if (affected == 0)
                {
                    throw new Exception("账户A1001不存在或余额不足");
                }
            }
            
            // 操作分区表2
            var insertTransaction = @"
            INSERT INTO transactions 
            (txn_id, from_account, to_account, amount, txn_time)
            VALUES 
            (UUID(), 'A1001', 'B2001', 1000, NOW())";
            
            using (var cmd2 = new MySqlCommand(insertTransaction, connection, transaction))
            {
                cmd2.ExecuteNonQuery();
            }
            
            // 操作分区表3
            var updateTargetAccount = @"
            UPDATE accounts 
            SET balance = balance + 1000 
            WHERE account_id = 'B2001'";
            
            using (var cmd3 = new MySqlCommand(updateTargetAccount, connection, transaction))
            {
                int affected = cmd3.ExecuteNonQuery();
                if (affected == 0)
                {
                    throw new Exception("目标账户B2001不存在");
                }
            }
            
            transaction.Commit();
            Console.WriteLine("分布式事务提交成功");
        }
        catch (Exception ex)
        {
            transaction.Rollback();
            Console.WriteLine($"分布式事务回滚: {ex.Message}");
            throw;
        }
    }
}

两阶段提交(2PC)模式

// 两阶段提交示例
using (var connection = new MySqlConnection(connectionString))
{
    connection.Open();
    
    // 第一阶段：准备
    using (var cmdPrepare1 = new MySqlCommand("XA START 'txn123'", connection))
    using (var cmdPrepare2 = new MySqlCommand("UPDATE accounts SET balance = balance - 500 WHERE account_id = 'A1001'", connection))
    using (var cmdPrepare3 = new MySqlCommand("XA END 'txn123'", connection))
    using (var cmdPrepare4 = new MySqlCommand("XA PREPARE 'txn123'", connection))
    {
        cmdPrepare1.ExecuteNonQuery();
        cmdPrepare2.ExecuteNonQuery();
        cmdPrepare3.ExecuteNonQuery();
        cmdPrepare4.ExecuteNonQuery();
    }
    
    try
    {
        // 第二阶段：提交
        using (var cmdCommit = new MySqlCommand("XA COMMIT 'txn123'", connection))
        {
            cmdCommit.ExecuteNonQuery();
            Console.WriteLine("两阶段提交完成");
        }
    }
    catch (Exception)
    {
        // 如果提交失败，尝试回滚
        using (var cmdRollback = new MySqlCommand("XA ROLLBACK 'txn123'", connection))
        {
            cmdRollback.ExecuteNonQuery();
            Console.WriteLine("两阶段提交失败，已回滚");
        }
        throw;
    }
}

性能监控与调优

查询执行计划分析

// 获取查询执行计划
var explainQuery = "EXPLAIN SELECT * FROM employees WHERE department_id = 101 AND salary > 10000";

using (var connection = new MySqlConnection(connectionString))
{
    connection.Open();
    
    using (var command = new MySqlCommand(explainQuery, connection))
    using (var reader = command.ExecuteReader())
    {
        Console.WriteLine("执行计划分析结果:");
        Console.WriteLine("ID\tSELECT_TYPE\tTABLE\tTYPE\tPOSSIBLE_KEYS\tKEY\tKEY_LEN\tREF\tROWS\tEXTRA");
        
        while (reader.Read())
        {
            Console.WriteLine($"{reader["id"]}\t{reader["select_type"]}\t" +
                            $"{reader["table"]}\t{reader["type"]}\t" +
                            $"{reader["possible_keys"]}\t{reader["key"]}\t" +
                            $"{reader["key_len"]}\t{reader["ref"]}\t" +
                            $"{reader["rows"]}\t{reader["Extra"]}");
        }
    }
}

性能监控查询

// 查询OceanBase性能视图
var performanceQueries = @"
-- 查看当前会话
SHOW PROCESSLIST;

-- 查看表统计信息
SHOW TABLE STATUS LIKE 'employees';

-- 查看索引统计信息
SHOW INDEX FROM employees;

-- 查看OceanBase系统视图
SELECT * FROM oceanbase.v$sql_audit ORDER BY request_time DESC LIMIT 10;";

using (var connection = new MySqlConnection(connectionString))
{
    connection.Open();
    
    using (var command = new MySqlCommand(performanceQueries, connection))
    {
        using (var reader = command.ExecuteReader())
        {
            do
            {
                Console.WriteLine($"--- {command.CommandText.Substring(0, 30)}... ---");
                
                for (int i = 0; i < reader.FieldCount; i++)
                {
                    Console.Write($"{reader.GetName(i)}\t");
                }
                Console.WriteLine();
                
                while (reader.Read())
                {
                    for (int i = 0; i < reader.FieldCount; i++)
                    {
                        Console.Write($"{reader[i]}\t");
                    }
                    Console.WriteLine();
                }
                Console.WriteLine();
            } while (reader.NextResult());
        }
    }
}

连接池监控

// 获取连接池状态
var poolStats = typeof(MySqlConnection).GetProperty("PoolStats", 
    System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Static);

if (poolStats != null)
{
    var stats = poolStats.GetValue(null);
    Console.WriteLine("连接池状态:");
    Console.WriteLine($"Number of pools: {stats.GetType().GetProperty("NumberOfPools").GetValue(stats)}");
    Console.WriteLine($"Available connections: {stats.GetType().GetProperty("Available").GetValue(stats)}");
    Console.WriteLine($"Connections in use: {stats.GetType().GetProperty("InUse").GetValue(stats)}");
}

异常处理与日志记录

常见异常处理

try
{
    using (var connection = new MySqlConnection(connectionString))
    {
        connection.Open();
        
        var query = "SELECT * FROM non_existing_table";
        using (var command = new MySqlCommand(query, connection))
        {
            command.ExecuteReader();
        }
    }
}
catch (MySqlException ex)
{
    switch (ex.Number)
    {
        case 1045: // 访问被拒绝
            Console.WriteLine("数据库访问被拒绝，请检查用户名和密码");
            break;
        case 1049: // 未知数据库
            Console.WriteLine($"指定的数据库不存在: {ex.Message}");
            break;
        case 1146: // 表不存在
            Console.WriteLine($"表不存在: {ex.Message}");
            // 尝试创建表或提示用户
            break;
        case 1213: // 死锁
            Console.WriteLine("发生死锁，请重试操作");
            break;
        case 2006: // 服务器已断开连接
            Console.WriteLine("与数据库的连接已断开，尝试重新连接");
            break;
        case 2013: // 查询期间丢失连接
            Console.WriteLine("查询期间连接丢失，请检查网络或重试");
            break;
        default:
            Console.WriteLine($"数据库错误({ex.Number}): {ex.Message}");
            break;
    }
    
    // 记录完整异常信息
    LogError(ex);
}
catch (Exception ex)
{
    Console.WriteLine($"发生意外错误: {ex.Message}");
    LogError(ex);
}

void LogError(Exception ex)
{
    // 实际项目中可以使用Log4Net、NLog等日志框架
    string logMessage = $"[{DateTime.Now}] ERROR: {ex.GetType().Name}\n" +
                       $"Message: {ex.Message}\n" +
                       $"Stack Trace:\n{ex.StackTrace}\n";
    
    if (ex is MySqlException mySqlEx)
    {
        logMessage += $"MySQL Error Number: {mySqlEx.Number}\n";
    }
    
    File.AppendAllText("db_errors.log", logMessage + new string('-', 50) + "\n");
}

重试机制实现

public T ExecuteWithRetry<T>(Func<T> operation, int maxRetries = 3, int delayMs = 1000)
{
    int retryCount = 0;
    
    while (true)
    {
        try
        {
            return operation();
        }
        catch (MySqlException ex) when (IsTransientError(ex) && retryCount < maxRetries)
        {
            retryCount++;
            Console.WriteLine($"遇到临时错误，正在进行第 {retryCount} 次重试: {ex.Message}");
            Thread.Sleep(delayMs * retryCount); // 指数退避
        }
        catch (Exception)
        {
            throw;
        }
    }
}

private bool IsTransientError(MySqlException ex)
{
    // 定义需要重试的错误代码
    int[] transientErrorNumbers = { 1213, 1205, 2006, 2013, 1040, 1317 };
    
    // 连接超时或死锁等临时性错误
    return transientErrorNumbers.Contains(ex.Number) || 
           ex.Message.Contains("deadlock") ||
           ex.Message.Contains("timeout");
}

// 使用重试机制
var result = ExecuteWithRetry(() => {
    using (var connection = new MySqlConnection(connectionString))
    {
        connection.Open();
        using (var cmd = new MySqlCommand("SELECT COUNT(*) FROM employees", connection))
        {
            return Convert.ToInt32(cmd.ExecuteScalar());
        }
    }
});
Console.WriteLine($"员工总数: {result}");

安全最佳实践

参数化查询防止SQL注入

// 不安全的拼接SQL方式 - 容易受到SQL注入攻击
var unsafeQuery = $"SELECT * FROM users WHERE username = '{userInput}' AND password = '{passwordInput}'";

// 安全的参数化查询方式
var safeQuery = "SELECT * FROM users WHERE username = @username AND password = @password";

using (var connection = new MySqlConnection(connectionString))
{
    connection.Open();
    
    using (var command = new MySqlCommand(safeQuery, connection))
    {
        command.Parameters.AddWithValue("@username", userInput);
        command.Parameters.AddWithValue("@password", passwordInput);
        
        using (var reader = command.ExecuteReader())
        {
            if (reader.HasRows)
            {
                Console.WriteLine("登录成功");
            }
            else
            {
                Console.WriteLine("用户名或密码错误");
            }
        }
    }
}

使用最小权限原则

// 为应用创建专用用户并授予最小必要权限
var createAppUser = @"
-- 创建只读用户
CREATE USER 'app_readonly'@'%' IDENTIFIED BY 'StrongPassword123!';
GRANT SELECT ON mydb.* TO 'app_readonly'@'%';

-- 创建读写用户
CREATE USER 'app_readwrite'@'%' IDENTIFIED BY 'EvenStrongerPassword456!';
GRANT SELECT, INSERT, UPDATE, DELETE ON mydb.* TO 'app_readwrite'@'%';

-- 创建仅能访问特定表的用户
CREATE USER 'report_user'@'%' IDENTIFIED BY 'ReportPassword789!';
GRANT SELECT ON mydb.sales_data TO 'report_user'@'%';
GRANT SELECT ON mydb.products TO 'report_user'@'%';";

using (var connection = new MySqlConnection(connectionString))
{
    connection.Open();
    
    foreach (var statement in createAppUser.Split(';'))
    {
        if (!string.IsNullOrWhiteSpace(statement))
        {
            using (var command = new MySqlCommand(statement, connection))
            {
                command.ExecuteNonQuery();
            }
        }
    }
    Console.WriteLine("安全用户创建完成");
}

敏感数据加密

// 使用AES加密敏感数据
public static string Encrypt(string plainText, string key)
{
    using (Aes aes = Aes.Create())
    {
        aes.Key = Encoding.UTF8.GetBytes(key);
        aes.IV = new byte[16]; // 在实际应用中应使用随机IV
        
        ICryptoTransform encryptor = aes.CreateEncryptor(aes.Key, aes.IV);
        
        using (MemoryStream ms = new MemoryStream())
        using (CryptoStream cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write))
        {
            using (StreamWriter sw = new StreamWriter(cs))
            {
                sw.Write(plainText);
            }
            return Convert.ToBase64String(ms.ToArray());
        }
    }
}

// 在数据库中存储加密数据
var insertSensitiveData = "INSERT INTO customers (id, name, encrypted_credit_card) VALUES (@id, @name, @card)";

using (var connection = new MySqlConnection(connectionString))
{
    connection.Open();
    
    string creditCardNumber = "4111111111111111";
    string encryptionKey = "my-secret-key-123"; // 实际应用中应从安全的地方获取
    
    using (var command = new MySqlCommand(insertSensitiveData, connection))
    {
        command.Parameters.AddWithValue("@id", 1001);
        command.Parameters.AddWithValue("@name", "张三");
        command.Parameters.AddWithValue("@card", Encrypt(creditCardNumber, encryptionKey));
        
        command.ExecuteNonQuery();
        Console.WriteLine("加密数据存储完成");
    }
}

ORM集成

使用Dapper进行数据访问

// 安装Dapper
// Install-Package Dapper

public class Employee
{
    public long Id { get; set; }
    public string Name { get; set; }
    public string Email { get; set; }
    public decimal Salary { get; set; }
    public DateTime HireDate { get; set; }
    public int DepartmentId { get; set; }
}

using Dapper;

// 查询示例
using (var connection = new MySqlConnection(connectionString))
{
    connection.Open();
    
    // 简单查询
    var employees = connection.Query<Employee>(
        "SELECT * FROM employees WHERE department_id = @deptId",
        new { deptId = 101 });
    
    foreach (var emp in employees)
    {
        Console.WriteLine($"{emp.Id}: {emp.Name}, {emp.Salary:C}");
    }
    
    // 多映射查询
    var sql = @"
    SELECT e.*, d.name AS department_name 
    FROM employees e 
    JOIN departments d ON e.department_id = d.id
    WHERE e.salary > @minSalary";
    
    var results = connection.Query<Employee, string, dynamic>(
        sql,
        (employee, departmentName) => 
        {
            return new { Employee = employee, Department = departmentName };
        },
        new { minSalary = 10000 },
        splitOn: "department_name");
    
    foreach (var item in results)
    {
        Console.WriteLine($"{item.Employee.Name} 在 {item.Department} 部门");
    }
    
    // 执行存储过程
    var parameters = new DynamicParameters();
    parameters.Add("@dept_id", 101);
    parameters.Add("@increase_percent", 5.0m);
    parameters.Add("@affected_rows", dbType: DbType.Int32, direction: ParameterDirection.Output);
    
    connection.Execute("increase_salary", parameters, commandType: CommandType.StoredProcedure);
    
    Console.WriteLine($"影响了 {parameters.Get<int>("@affected_rows")} 行数据");
}

使用Entity Framework Core

// 安装EF Core和相关包
// Install-Package Microsoft.EntityFrameworkCore
// Install-Package Pomelo.EntityFrameworkCore.MySql

public class AppDbContext : DbContext
{
    public DbSet<Employee> Employees { get; set; }
    public DbSet<Department> Departments { get; set; }
    
    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.UseMySql(connectionString, 
            ServerVersion.AutoDetect(connectionString),
            options => 
            {
                options.EnableRetryOnFailure(
                    maxRetryCount: 5,
                    maxRetryDelay: TimeSpan.FromSeconds(30),
                    errorNumbersToAdd: null);
            });
    }
    
    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        // 配置实体
        modelBuilder.Entity<Employee>(entity =>
        {
            entity.ToTable("employees");
            entity.HasKey(e => e.Id);
            entity.Property(e => e.Name).IsRequired().HasMaxLength(100);
            entity.Property(e => e.Email).HasMaxLength(100);
            entity.Property(e => e.Salary).HasColumnType("DECIMAL(15,2)");
            entity.HasIndex(e => e.DepartmentId).HasDatabaseName("idx_department");
            
            entity.HasOne<Department>()
                .WithMany()
                .HasForeignKey(e => e.DepartmentId);
        });
        
        modelBuilder.Entity<Department>(entity =>
        {
            entity.ToTable("departments");
            entity.HasKey(d => d.Id);
            entity.Property(d => d.Name).IsRequired().HasMaxLength(50);
        });
    }
}

// 使用EF Core进行CRUD操作
using (var context = new AppDbContext())
{
    // 添加数据
    var newDept = new Department { Name = "研发部" };
    context.Departments.Add(newDept);
    
    var newEmp = new Employee 
    { 
        Name = "赵六", 
        Email = "zhaoliu@example.com",
        Salary = 18000,
        HireDate = DateTime.Now,
        Department = newDept
    };
    context.Employees.Add(newEmp);
    
    context.SaveChanges();
    
    // 查询数据
    var highSalaryEmps = context.Employees
        .Where(e => e.Salary > 15000)
        .Include(e => e.Department)
        .ToList();
    
    foreach (var emp in highSalaryEmps)
    {
        Console.WriteLine($"{emp.Name} 在 {emp.Department?.Name} 部门，薪资 {emp.Salary:C}");
    }
    
    // 更新数据
    var empToUpdate = context.Employees.Find(1001L);
    if (empToUpdate != null)
    {
        empToUpdate.Salary *= 1.1m;
        context.SaveChanges();
    }
    
    // 删除数据
    var empToDelete = context.Employees.Find(1002L);
    if (empToDelete != null)
    {
        context.Employees.Remove(empToDelete);
        context.SaveChanges();
    }
}

实战案例

电商系统数据访问层实现

public interface IProductRepository
{
    Task<Product> GetByIdAsync(long id);
    Task<IEnumerable<Product>> SearchAsync(string keyword, int page, int pageSize);
    Task<long> AddAsync(Product product);
    Task<bool> UpdateAsync(Product product);
    Task<bool> DeleteAsync(long id);
    Task<bool> UpdateStockAsync(long productId, int quantityChange);
}

public class ProductRepository : IProductRepository
{
    private readonly string _connectionString;
    
    public ProductRepository(string connectionString)
    {
        _connectionString = connectionString;
    }
    
    public async Task<Product> GetByIdAsync(long id)
    {
        using (var connection = new MySqlConnection(_connectionString))
        {
            await connection.OpenAsync();
            
            var sql = @"
            SELECT p.*, c.name AS category_name 
            FROM products p
            LEFT JOIN categories c ON p.category_id = c.id
            WHERE p.id = @id";
            
            var product = await connection.QueryFirstOrDefaultAsync<Product>(sql, new { id });
            return product;
        }
    }
    
    public async Task<IEnumerable<Product>> SearchAsync(string keyword, int page, int pageSize)
    {
        using (var connection = new MySqlConnection(_connectionString))
        {
            await connection.OpenAsync();
            
            var offset = (page - 1) * pageSize;
            var sql = @"
            SELECT p.*, c.name AS category_name 
            FROM products p
            LEFT JOIN categories c ON p.category_id = c.id
            WHERE p.name LIKE @keyword OR p.description LIKE @keyword
            ORDER BY p.id
            LIMIT @pageSize OFFSET @offset";
            
            var products = await connection.QueryAsync<Product>(
                sql, 
                new { 
                    keyword = $"%{keyword}%", 
                    pageSize, 
                    offset 
                });
            
            return products;
        }
    }
    
    public async Task<long> AddAsync(Product product)
    {
        using (var connection = new MySqlConnection(_connectionString))
        {
            await connection.OpenAsync();
            
            var sql = @"
            INSERT INTO products 
            (name, description, price, stock, category_id, created_at, updated_at)
            VALUES 
            (@Name, @Description, @Price, @Stock, @CategoryId, NOW(), NOW());
            SELECT LAST_INSERT_ID();";
            
            var id = await connection.ExecuteScalarAsync<long>(sql, product);
            return id;
        }
    }
    
    public async Task<bool> UpdateAsync(Product product)
    {
        using (var connection = new MySqlConnection(_connectionString))
        {
            await connection.OpenAsync();
            
            var sql = @"
            UPDATE products SET 
                name = @Name,
                description = @Description,
                price = @Price,
                stock = @Stock,
                category_id = @CategoryId,
                updated_at = NOW()
            WHERE id = @Id";
            
            var affected = await connection.ExecuteAsync(sql, product);
            return affected > 0;
        }
    }
    
    public async Task<bool> DeleteAsync(long id)
    {
        using (var connection = new MySqlConnection(_connectionString))
        {
            await connection.OpenAsync();
            
            var sql = "DELETE FROM products WHERE id = @id";
            var affected = await connection.ExecuteAsync(sql, new { id });
            return affected > 0;
        }
    }
    
    public async Task<bool> UpdateStockAsync(long productId, int quantityChange)
    {
        using (var connection = new MySqlConnection(_connectionString))
        {
            await connection.OpenAsync();
            
            // 使用事务确保数据一致性
            using (var transaction = await connection.BeginTransactionAsync())
            {
                try
                {
                    // 检查库存是否足够
                    var currentStock = await connection.ExecuteScalarAsync<int>(
                        "SELECT stock FROM products WHERE id = @productId FOR UPDATE",
                        new { productId }, transaction);
                    
                    if (currentStock + quantityChange < 0)
                    {
                        throw new InvalidOperationException("库存不足");
                    }
                    
                    // 更新库存
                    var sql = @"
                    UPDATE products 
                    SET stock = stock + @quantityChange, 
                        updated_at = NOW()
                    WHERE id = @productId";
                    
                    var affected = await connection.ExecuteAsync(
                        sql, 
                        new { productId, quantityChange }, 
                        transaction);
                    
                    await transaction.CommitAsync();
                    return affected > 0;
                }
                catch
                {
                    await transaction.RollbackAsync();
                    throw;
                }
            }
        }
    }
}

报表生成服务

public class ReportService
{
    private readonly string _connectionString;
    
    public ReportService(string connectionString)
    {
        _connectionString = connectionString;
    }
    
    public async Task<SalesReport> GenerateSalesReport(DateTime startDate, DateTime endDate)
    {
        using (var connection = new MySqlConnection(_connectionString))
        {
            await connection.OpenAsync();
            
            var report = new SalesReport
            {
                StartDate = startDate,
                EndDate = endDate,
                GenerationDate = DateTime.Now
            };
            
            // 获取总销售额
            var totalSalesSql = @"
            SELECT IFNULL(SUM(amount), 0) 
            FROM orders 
            WHERE order_date BETWEEN @startDate AND @endDate 
            AND status = 'completed'";
            
            report.TotalSales = await connection.ExecuteScalarAsync<decimal>(
                totalSalesSql, new { startDate, endDate });
            
            // 按产品类别统计
            var byCategorySql = @"
            SELECT 
                c.name AS category,
                COUNT(o.id) AS order_count,
                SUM(o.amount) AS total_amount
            FROM orders o
            JOIN order_items oi ON o.id = oi.order_id
            JOIN products p ON oi.product_id = p.id
            JOIN categories c ON p.category_id = c.id
            WHERE o.order_date BETWEEN @startDate AND @endDate
            AND o.status = 'completed'
            GROUP BY c.id, c.name
            ORDER BY total_amount DESC";
            
            report.SalesByCategory = (await connection.QueryAsync<CategorySales>(
                byCategorySql, new { startDate, endDate })).ToList();
            
            // 按地区统计
            var byRegionSql = @"
            SELECT 
                r.name AS region,
                COUNT(o.id) AS order_count,
                SUM(o.amount) AS total_amount
            FROM orders o
            JOIN customers c ON o.customer_id = c.id
            JOIN regions r ON c.region_id = r.id
            WHERE o.order_date BETWEEN @startDate AND @endDate
            AND o.status = 'completed'
            GROUP BY r.id, r.name
            ORDER BY total_amount DESC";
            
            report.SalesByRegion = (await connection.QueryAsync<RegionSales>(
                byRegionSql, new { startDate, endDate })).ToList();
            
            // 销售趋势（按天）
            var trendSql = @"
            SELECT 
                DATE(order_date) AS day,
                COUNT(id) AS order_count,
                SUM(amount) AS daily_sales
            FROM orders
            WHERE order_date BETWEEN @startDate AND @endDate
            AND status = 'completed'
            GROUP BY DATE(order_date)
            ORDER BY day";
            
            report.DailyTrends = (await connection.QueryAsync<DailySalesTrend>(
                trendSql, new { startDate, endDate })).ToList();
            
            return report;
        }
    }
    
    public async Task<byte[]> ExportSalesReportToExcel(DateTime startDate, DateTime endDate)
    {
        var report = await GenerateSalesReport(startDate, endDate);
        
        using (var package = new ExcelPackage())
        {
            var worksheet = package.Workbook.Worksheets.Add("销售报表");
            
            // 添加报表标题
            worksheet.Cells["A1"].Value = "销售报表";
            worksheet.Cells["A1:D1"].Merge = true;
            worksheet.Cells["A1"].Style.Font.Bold = true;
            worksheet.Cells["A1"].Style.Font.Size = 16;
            
            // 添加日期范围
            worksheet.Cells["A2"].Value = $"日期范围: {startDate:yyyy-MM-dd} 至 {endDate:yyyy-MM-dd}";
            worksheet.Cells["A2:D2"].Merge = true;
            
            // 添加生成日期
            worksheet.Cells["A3"].Value = $"生成时间: {report.GenerationDate:yyyy-MM-dd HH:mm:ss}";
            worksheet.Cells["A3:D3"].Merge = true;
            
            // 添加总销售额
            worksheet.Cells["A5"].Value = "总销售额:";
            worksheet.Cells["B5"].Value = report.TotalSales;
            worksheet.Cells["B5"].Style.Numberformat.Format = "¥#,##0.00";
            
            // 按类别添加销售数据
            worksheet.Cells["A7"].Value = "按产品类别统计";
            worksheet.Cells["A7:C7"].Merge = true;
            worksheet.Cells["A7"].Style.Font.Bold = true;
            
            int row = 8;
            worksheet.Cells[row, 1].Value = "类别";
            worksheet.Cells[row, 2].Value = "订单数";
            worksheet.Cells[row, 3].Value = "销售额";
            worksheet.Cells[row, 1, row, 3].Style.Font.Bold = true;
            
            foreach (var item in report.SalesByCategory)
            {
                row++;
                worksheet.Cells[row, 1].Value = item.Category;
                worksheet.Cells[row, 2].Value = item.OrderCount;
                worksheet.Cells[row, 3].Value = item.TotalAmount;
                worksheet.Cells[row, 3].Style.Numberformat.Format = "¥#,##0.00";
            }
            
            // 按地区添加销售数据
            row += 2;
            worksheet.Cells[row, 1].Value = "按地区统计";
            worksheet.Cells[row, 3].Merge = true;
            worksheet.Cells[row, 1].Style.Font.Bold = true;
            
            row++;
            worksheet.Cells[row, 1].Value = "地区";
            worksheet.Cells[row, 2].Value = "订单数";
            worksheet.Cells[row, 3].Value = "销售额";
            worksheet.Cells[row, 1, row, 3].Style.Font.Bold = true;
            
            foreach (var item in report.SalesByRegion)
            {
                row++;
                worksheet.Cells[row, 1].Value = item.Region;
                worksheet.Cells[row, 2].Value = item.OrderCount;
                worksheet.Cells[row, 3].Value = item.TotalAmount;
                worksheet.Cells[row, 3].Style.Numberformat.Format = "¥#,##0.00";
            }
            
            // 自动调整列宽
            worksheet.Cells[worksheet.Dimension.Address].AutoFitColumns();
            
            return package.GetAsByteArray();
        }
    }
}

public class SalesReport
{
    public DateTime StartDate { get; set; }
    public DateTime EndDate { get; set; }
    public DateTime GenerationDate { get; set; }
    public decimal TotalSales { get; set; }
    public List<CategorySales> SalesByCategory { get; set; }
    public List<RegionSales> SalesByRegion { get; set; }
    public List<DailySalesTrend> DailyTrends { get; set; }
}

public class CategorySales
{
    public string Category { get; set; }
    public int OrderCount { get; set; }
    public decimal TotalAmount { get; set; }
}

public class RegionSales
{
    public string Region { get; set; }
    public int OrderCount { get; set; }
    public decimal TotalAmount { get; set; }
}

public class DailySalesTrend
{
    public DateTime Day { get; set; }
    public int OrderCount { get; set; }
    public decimal DailySales { get; set; }
}

总结

本文详细介绍了在.NET环境下开发OceanBase应用程序的各个方面，包括：

1. 基础操作：连接管理、CRUD操作、事务处理
2. 性能优化：批量操作、连接池、查询优化
3. 高级特性：JSON处理、分布式事务、存储过程
4. 安全实践：参数化查询、权限控制、数据加密
5. ORM集成：Dapper和Entity Framework Core的使用
6. 实战案例：电商系统数据访问层和报表服务的实现

OceanBase作为一款高性能分布式数据库，与.NET生态系统的结合可以构建出强大、可靠的企业级应用。通过合理利用OceanBase的特性和.NET的强大功能，开发者可以构建出高性能、高可用的分布式应用系统。

在实际开发中，建议根据具体业务场景选择合适的访问方式，对于性能要求高的场景可以使用原生ADO.NET或Dapper，对于需要快速开发的场景可以使用Entity Framework Core。同时，要特别注意分布式环境下的事务处理和性能优化，充分利用OceanBase的分布式特性。