How to write custom storage engines and triggers in MySQL using C#

How to use C# to write custom storage engines and triggers in MySQL

Introduction:
MySQL is a very popular relational database management system. It provides many built-in storage engines and triggers to meet various needs. However, sometimes we need to customize storage engines and triggers according to specific needs. This article will introduce how to use C# to write custom storage engines and triggers in MySQL, and provide code examples.

1. Custom storage engine:

1. Preparation:
First, we need to install Visual Studio and MySQL Connector/NET. Then create a new C# class library project in Visual Studio.

2. Import dependencies:
In the C# class library project, we need to import the reference to MySQL Connector/NET. Right-click the project in Solution Explorer, select "Manage NuGet Packages", search for and install the "MySQL.Data" package.

3. Write storage engine code:
Create a new class and use the following code in the class to write the logic of the storage engine.

using System;
using MySql.Data.MySqlClient;

public class CustomStorageEngine : MySqlStorageEngine
{
    public CustomStorageEngine(MySqlConnectionStringBuilder connectionStringBuilder) : base(connectionStringBuilder)
    {
        // 存储引擎初始化逻辑
    }

    public override MySqlStorageEngineTransaction BeginTransaction()
    {
        // 开启一个事务
        return new CustomTransaction(this);
    }
    
    // 实现其他存储引擎方法
}

public class CustomTransaction : MySqlStorageEngineTransaction
{
    public CustomTransaction(MySqlStorageEngine storageEngine) : base(storageEngine)
    {
        // 事务初始化逻辑
    }

    public override void Commit()
    {
        // 提交事务逻辑
    }

    public override void Rollback()
    {
        // 回滚事务逻辑
    }
}

4. Register storage engine:
Enter the MySQL command line or MySQL Workbench, and execute the following command on the command line or workbench to register a custom storage engine.

INSTALL PLUGIN custom_engine SONAME 'custom_engine.dll';

Note that custom_engine needs to be replaced with the name of your storage engine, and custom_engine.dll needs to be replaced with the name of the storage engine DLL file generated by your compilation.

2. Custom triggers:

1. Preparation:
In MySQL, triggers are used to set specific operations on tables in the database to occur when specific events occur. trigger action.

2. Import dependencies:
In the C# class library project, we need to import the reference to MySQL Connector/NET. Right-click the project in Solution Explorer, select "Manage NuGet Packages", search for and install the "MySQL.Data" package.

3. Write trigger code:
Create a new class and use the following code to write the logic of the trigger in the class.

using System;
using MySql.Data.MySqlClient;

public class CustomTrigger
{
    public static void InsertTrigger(MySqlConnection connection, string triggerName, string tableName, string insertColumn)
    {
        MySqlCommand command = new MySqlCommand();
        command.Connection = connection;
        command.CommandText = $"CREATE TRIGGER {triggerName} AFTER INSERT ON {tableName} FOR EACH ROW BEGIN // 触发器逻辑 END";
        command.ExecuteNonQuery();
    }
    
    public static void UpdateTrigger(MySqlConnection connection, string triggerName, string tableName, string updateColumn)
    {
        MySqlCommand command = new MySqlCommand();
        command.Connection = connection;
        command.CommandText = $"CREATE TRIGGER {triggerName} AFTER UPDATE ON {tableName} FOR EACH ROW BEGIN // 触发器逻辑 END";
        command.ExecuteNonQuery();
    }
    
    // 实现其他触发器方法
}

4. Use custom triggers:
Open the MySQL command line or MySQL Workbench, and execute the following commands in the command line or workbench to use custom triggers.

USE your_database;
DELIMITER //
CREATE TRIGGER your_trigger AFTER INSERT ON your_table FOR EACH ROW 
BEGIN
    CALL your_stored_procedure(); // 调用自定义存储过程或者其他逻辑
END //
DELIMITER ;

The above code uses a custom trigger your_trigger, which is triggered when a new row is inserted into table your_table, and calls the stored procedure your_stored_procedure .

Summary:
This article introduces how to use C# to write custom storage engines and triggers in MySQL, and provides corresponding code examples. By customizing storage engines and triggers, we can meet more complex database requirements and provide more flexible data management and processing methods. Hope this article can be helpful to you.

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