Establish first connection to the database

Establish first connection to the database

Prerequisites

• MySQL server is installed and running

• You know the IP address of the server

• You have a MySQL username and password

• A database has already been created

1

Declare variables

VAR
    // Connection parameters
    sHost           : STRING := '192.168.1.100';    // IP address of your MySQL server
    uiPort          : UINT := 3306;                 // Default MySQL port
    sDatabase       : STRING := 'testdb';           // Name of your database
    sUsername       : STRING := 'root';             // Your username
    sPassword       : STRING := 'MeinPasswort123';  // Your password
    
    // Control
    xDoOpen         : BOOL := FALSE;                // Trigger to open
    xConnected      : BOOL := FALSE;                // Status: connected
    
    // Function block
    MySQL_ConnString : MySQL_ConnectionString;      // Connection object
    fbMySQL_Open     : MySQL_Open;                  // Function block
    
    // Error handling
    eError          : ERROR;                        // Error code
    sExecuteState   : STRING(200);                  // Status message
END_VAR

2

Open connection - code

// Open connection when xDoOpen is TRUE
IF xDoOpen THEN
    fbMySQL_Open(
        sHost           := '192.168.1.100',         // CHANGE: your server IP
        uiPort          := 3306,
        sDatabase       := 'testdb',                // CHANGE: your database name
        sUsername       := 'root',                  // CHANGE: your username
        sPassword       := 'MeinPasswort123',       // CHANGE: your password
        xStart          := xDoOpen,
        MySQL_Connection:= MySQL_ConnString,
        xConnected      => xConnected,
        eError          => eError,
        sExeute_State   => sExecuteState
    );
END_IF

3

Test connection

In online mode:

1. Set xDoOpen to TRUE

2. Monitor the variables:

   • xConnected should TRUE become

   • eError should 0 remain (no error)

   • sExecuteState shows "SUCCESSFULLY CONNECTED WITH DATABASE"

4

Check status

// Output status
IF xConnected THEN
    // Connection successful!
    // You can now execute SQL commands here
ELSIF eError <> ERROR.NO_ERROR THEN
    // An error occurred
    // Check eError and sExecuteState for details
END_IF

Important values to adjust

Parameter	Example value	Where do I find the value?
sHost	'192.168.1.100'	IP address of your server (for local server: '127.0.0.1' or 'localhost')
uiPort	3306	Default port, normally do not change
sDatabase	'testdb'	Name of your database in phpMyAdmin or MySQL Workbench
sUsername	'root'	MySQL username (default: 'root')
sPassword	'MeinPasswort123'	Password you set during MySQL installation

Troubleshooting

Error	Cause	Solution
eError = 1	Server unreachable	Check IP address and network connection
eError = 2	Authentication failed	Check username and password
eError = 3	Timeout	Check firewall settings, port 3306 must be open
eError = 4	Database does not exist	Check database name, create database if necessary