C# を使用して MySQL でカスタム トリガーとストアド プロシージャを作成する方法

DELIMITER //

CREATE PROCEDURE RegisterTrigger()
BEGIN
    DECLARE @TriggerName VARCHAR(50);
    DECLARE @TableName VARCHAR(50);
    DECLARE @BeforeOrAfter VARCHAR(6);
    DECLARE @EventType VARCHAR(50);
    DECLARE @SqlStatement VARCHAR(MAX);

    -- 设置触发器名称、表名称、触发时间和事件类型
    SET @TriggerName = 'MyTrigger';
    SET @TableName = 'MyTable';
    SET @BeforeOrAfter = 'AFTER';
    SET @EventType = 'INSERT';

    -- 构建SQL语句
    SET @SqlStatement = 'CREATE TRIGGER '+ @TriggerName +' '+ @BeforeOrAfter +' '+@EventType+' ON '+ @TableName +' FOR EACH ROW BEGIN /*执行的操作*/ END ;';

    -- 执行SQL语句
    PREPARE stmt FROM @SqlStatement;
    EXECUTE stmt;
    DEALLOCATE PREPARE stmt;
END //

DELIMITER ;

using MySql.Data.MySqlClient;

class Program
{
    static void Main(string[] args)
    {
        // 连接到MySQL数据库
        string connStr = "server=localhost;user=root;database=myDatabase;port=3306;password=myPassword;";
        MySqlConnection conn = new MySqlConnection(connStr);
        conn.Open();

        // 创建一个命令对象
        MySqlCommand cmd = new MySqlCommand();
        cmd.Connection = conn;
        cmd.CommandText = "RegisterTrigger";
        cmd.CommandType = CommandType.StoredProcedure;

        // 执行存储过程
        cmd.ExecuteNonQuery();

        // 关闭数据库连接
        conn.Close();
    }
}

DELIMITER //

CREATE PROCEDURE GetEmployees(IN DepartmentId INT)
BEGIN
    SELECT * FROM Employees WHERE DepartmentId = DepartmentId;
END //

DELIMITER ;

using MySql.Data.MySqlClient;

class Program
{
    static void Main(string[] args)
    {
        // 连接到MySQL数据库
        string connStr = "server=localhost;user=root;database=myDatabase;port=3306;password=myPassword;";
        MySqlConnection conn = new MySqlConnection(connStr);
        conn.Open();

        // 创建一个命令对象
        MySqlCommand cmd = new MySqlCommand();
        cmd.Connection = conn;
        cmd.CommandText = "GetEmployees";
        cmd.CommandType = CommandType.StoredProcedure;

        // 添加参数
        cmd.Parameters.AddWithValue("@DepartmentId", 1);

        // 执行存储过程并获取结果集
        MySqlDataReader rdr = cmd.ExecuteReader();
        while (rdr.Read())
        {
            Console.WriteLine(rdr["EmployeeId"] + " " + rdr["EmployeeName"]);
        }
        rdr.Close();

        // 关闭数据库连接
        conn.Close();
    }
}