C# connect and use MySQL database detailed tutorial

C# connect to MySQL need to add a reference to connect to MySQL

本文将介绍3种添加MySQL引用的方法，以及连接MySQL和使用MySQL的教程

C# quotes MySQL steps:

the first method:

1. Download mysql.data.dll
2. Place the file in the project directory
3. In the VS2019 project, refer to the mysql.data.dll file and
   enter the DLL official website to download the mysql.data.dllfile ( 可自选版本下载),
   
   click download to
   
   complete the download, then unzip the mysql.data.dllfile
   
   and right-click in the project to reference -> add reference -> browse -> select the MySql.Data.dllfile -> OK. The operation is as follows:

Select reference

Right-click and click Add Reference

Click to browse

Choose the mysql.data.dllstorage path

After adding the reference, click OK

记住勾选dll文件

Click on the reference, you can see that the mysql.datareference has been added ( 引用属性里可以看到引用详细信息) the

second method

1. Add dynamic link library file: download connector/net on the official website
2. Place the file in the project directory
3. In the VS2019 project, reference the mysql.data.dll file

Go to MySQL official website to download the dynamic link library file

Click Download

Click to No thanks, just start my download.start downloading

Double click the program

Click Next

Choose installation type

The following is the description of the three installation types:
Typical>Typical: usually install the most common program functions. Recommend to most users.
Custom>Customization: Allow users to choose which program features will be installed and where they will be installed. It is recommended for advanced users.
Complete>Complete: All program functions will be installed. The most disk space is required.

一般选择第一个Typical即可。

Click install to install,

see the progress bar, and wait for the installation.

The installation is complete

Select reference

Right-click and click Add Reference

mysql.data.dllDefault storage path

Since we installed the dynamic link library file, go directly to the C drive and select the dynamic link library file
path : C:\Program Files (x86)\MySQL\MySQL Connector Net 8.0.23\Assemblies\v4.5.2
you can see a lot of dynamic link library files.

Of course, you can also use mysql.data.dllthe file path that Everything quickly locates .

Input mysql.data.dllcan quickly locate

Continue with the steps you just added the reference! ! !

Click to browse

Choose the mysql.data.dllstorage path

Find the dll file path : C:\Program Files (x86)\MySQL\MySQL Connector Net 8.0.23\Assemblies\v4.5.2
click Add to

check, click OK to

view the reference. The

third method:
直接在visual studio内添加mysql方案包
select in the menu bar, 工具

click NuGet包管理器(N)

click 管理解决方案的NuGet程序包(N).
enter, mysql

select the official ( 作者Oracle), check the item,

click install,

click OK ( 添加成功后会弹窗提示),

click I accept the

installation is successful

After completing the above operations, you can connect to the database through the code.

C# uses MySQL

Use usingto call the mysqlconnection, so that the connection can be automatically closed after use to connect
to the database, and there is no need to manually write a method to close the database.

Import namespaceusing MySql.Data.MySqlClient;

• data source= Server IP address;
• database= Database name;
• user id= Database user name;
• password= Database password;
• pooling= Whether to put in the connection pool;
• charset= Encoding method;

Parameters for
string connectstring= "data source=localhost;database=test1;user id=root;password=root;pooling=true;charset=utf8;";
connecting to the database: the method of connecting to the database:
MySqlConnection msc = new MySqlConnection(connectstring);

//导入命名空间
using MySql.Data.MySqlClient;

static void Main(string[] args)
        {
    
    
            //定义mysql连接字符串
            string constring = "data source=localhost;database=test1;user id=root;password=root;pooling=true;charset=utf8;";
            //连接mysql
            MySqlConnection msc = new MySqlConnection(constring);
        }

Detailed analysis of MySQL connection string parameters

Usually the database connection string is:

Database=dbname;Data Source=192.168.1.1;Port=3306;User Id=root;Password=****;Charset=utf8;TreatTinyAsBoolean=false;

parameter	Description
Server，host, data source, datasource, address, addr, network address	Database location (any of the above keywords can be used)
Database，initial catalog	data storage name
Port	socket port, default 3306
ConnectionProtocol，protocol	Connection protocol, default Sockets
PipeName ， pipe	Connection pipeline, default MYSQL
UseCompression，compress	Whether the connection is compressed, the default is false
AllowBatch	Whether to allow multiple SQL statements to be executed at one time, the default is true
Logging	Whether to enable the log, the default is false
SharedMemoryName	The name of the memory share, default MYSQL
UseOldSyntax，old syntax, oldsyntax	Is it compatible with the old version of the syntax, the default is false
ConnectionTimeout，connection timeout	Connection timeout waiting time, default 15s
DefaultCommandTimeout，command timeout	MySqlCommand timeout time, the default is 30s
UserID, uid, username, user name, user	Database login account
Password，pwd	login password
PersistSecurityInfo	Whether to keep sensitive information, the default is false
Encrypt	Encrypt
CertificateFile	Certificate file (.pfx) format
CertificatePassword	Certificate password
CertificateStoreLocation	Where to store the certificate
CertificateThumbprint	Certificate fingerprint
AllowZeroDateTime	Whether the date and time can be zero, the default is false
ConvertZeroDateTime	Whether the zero date and time are converted to DateTime.MinValue, the default is false
UseUsageAdvisor, usage advisor	Whether to enable the assistant, it will affect the performance of the database, the default is false
ProcedureCacheSize，procedure cache, procedurecache	Several stored procedures can be cached at the same time, 0 is forbidden, the default is 25
UsePerformanceMonitor，userperfmon, perfmon	Whether to enable performance monitoring, the default is false
IgnorePrepare	Whether to ignore the Prepare() call, the default is true
UseProcedureBodies,procedure bodies	Whether to check the validity of the stored procedure body and parameters, the default is true
AutoEnlist	Whether to automatically use the active connection, the default is true
RespectBinaryFlags	Whether to respond to the binary flag of the metadata on the column, the default is true
TreatTinyAsBoolean	Whether to treat the TINYINT(1) column as a boolean, the default is true
AllowUserVariables	Whether to allow user variables to appear in SQL, the default is false
InteractiveSession，interactive	Whether the session allows interaction, the default is false
FunctionsReturnString	Whether all server functions are processed according to the return string, the default is false
UseAffectedRows	Whether to replace the number of rows found with the number of affected rows to return data, the default is false
OldGuids	Whether to use the binary(16) column as Guids, the default is false
Keepalive	The number of seconds to keep the TCP connection, the default is 0, not keep.
ConnectionLifeTime	The minimum time (in seconds) that the connection remains in the connection pool before being destroyed. Default 0
Pooling	Whether to use thread pool, default true
MinimumPoolSize, min pool size	The minimum number of threads allowed in the thread pool, the default is 0
MaximumPoolSize，max pool size	The maximum number of threads allowed in the thread pool, the default is 100
ConnectionReset	Whether to automatically reset after the connection expires, the default is false
CharacterSet, charset	The character set used to request the connection from the server, default: none
TreatBlobsAsUTF8	Whether binary blobs are treated as utf8, the default is false
BlobAsUTF8IncludePattern	The matching mode of the column. Once matched, it will be processed as utf8. Default: none
SslMode	Whether to enable SSL connection mode, default: MySqlSslMode.None

SQL command execution method:

ExcuteNonQuery执行增改删：

1. insert(increase)
2. updata(change)
3. delete(delete)

ExcuteReader: Execute a multi-line query and return the DataReader object
ExcuteScalar: execute a single-line query and return the first row of data in the query result
Create a MySQLcommand object: MySqlCommand cmd = new MySqlCommand(sql, msc);
read a DataReadersingle row of object data: reader.Read()
get a single row of field data: reader.GetInt32(0); reader.GetString(1);**

//导入命名空间
using MySql.Data.MySqlClient;

static void Main(string[] args)
        {
    
    
            //定义mysql连接字符串
            string constring = "data source=localhost;database=test1;user id=root;password=root;pooling=true;charset=utf8;";
            //连接mysql
            MySqlConnection msc = new MySqlConnection(constring);
             #region MySQL操作
        //写入sql语句
        string sql = "select * from user";
        //创建命令对象
        MySqlCommand cmd = new MySqlCommand(sql, msc);
        //打开数据库连接
        msc.Open();
        //执行命令,ExcuteReader返回的是DataReader对象
        MySqlDataReader reader = cmd.ExecuteReader();
        //循环单行读取数据，当读取为null时，就退出循环
        while (reader.Read())
        {
    
    
            //输出第一列字段值
            Console.Write(reader.GetInt32(0) + "\t");
            //Console.Write(reader.GetInt32("id") + "\t");

            //判断字段"username"是否为null，为null数据转换会失败
            if (!reader.IsDBNull(1))
            {
    
    
                //输出第二列字段值
                Console.Write(reader.GetString(1) + "\t");
                //Console.Write(reader.GetString("username") + "\t");
            }
            //判断字段"password"是否为null，为null数据转换会失败
            if (!reader.IsDBNull(2))
            {
    
    
                //输出第三列字段值
                Console.Write(reader.GetString(2) + "\n");
                //Console.Write(reader.GetString("password") + "\t");
            }
        }
    }
   
   			 Console.ReadKey();
        }