# 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

{% stepper %}
{% step %}

#### Declare variables

```iecst
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
```

{% endstep %}

{% step %}

#### 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
```

{% endstep %}

{% step %}

#### 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"

{% endstep %}

{% step %}

#### Check status

```iecst
// 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
```

{% endstep %}
{% endstepper %}

#### 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 |