MySQL / MariaDB

Before You Start

• Keep your MySQL or MariaDB server reachable from the machine running the game or editor.
• Know the host, schema/database name, username, password, and port. The default MySQL port is 3306.
• Create a database user with only the permissions your Blueprint flow needs.

Where the SQL Session Lives

The live MySQL session is owned by the MySQL Game Instance subsystem, not by the level actor. Open Level destroys world actors. It does not close the SQL connection, drop Connection IDs, or cancel in-flight queries.

Blueprint Connection Steps

1. Place a MySQLDBConnectionActor in the map that first needs the database, or spawn the plugin's BP_MySQLDBConnectionActor.
2. On login, BeginPlay, or your setup event, call CreateNewConnection with Server, DBName, UserID, Password, and Port.
3. Add the actor event OnConnectionStateChanged. Store the returned ConnectionID when Connection Status is true.
4. If a widget, Game Instance, or Player Controller will outlive that map, also get Get MySQL Subsystem and bind the subsystem's On Connection State Changed, On Query Select Status Changed, and On Query Update Status Changed.
5. Optional: assign a MySQLConnectionOptions asset on the actor for SSL, timeout, read-only, or multi-result settings.

After Open Level

1. Place a MySQL connection actor in the destination map as well, including the login map if you return there.
2. That new actor registers with the Game Instance subsystem on BeginPlay. It does not close existing connections.
3. From a persistent widget, call Get MySQL Subsystem, then Get Active Connection Actor. Do not keep a hard reference to the actor from the previous map.
4. Call Has Connection with your stored ConnectionID. If it is still valid, run SelectDataFromQuery or UpdateDataFromQuery on the new actor with that same ID.
5. Only call CreateNewConnection again if you actually need another SQL session.

Run a Select Query

1. Wait until OnConnectionStateChanged reports a successful connection and a ConnectionID.
2. Call SelectDataFromQuery with that ConnectionID and your SQL select statement.

SELECT id, display_name, coins
FROM players
ORDER BY coins DESC
LIMIT 10;

3. Use OnQuerySelectStatusChanged on the current actor, or the matching subsystem event if the widget outlives the map.
4. On success, read Result By Column (MySQLDataTable) or Result By Row (MySQLDataRow).
5. Match the event's QueryID if several selects can be in flight at once.

Run an Insert, Update, or Delete

1. Call UpdateDataFromQuery with the same ConnectionID.
2. Use OnQueryUpdateStatusChanged to show success or the returned error text.
3. Use UpdateDataFromMultipleQueries when you need several statements in one queued task.

UPDATE players
SET coins = coins + 100
WHERE id = 42;

Using the Dedicated MySQL Actor

1. Place one connection actor per map that needs to talk to MySQL. Several actors in the same play session share the Game Instance session.
2. Call CreateNewConnection. The ConnectionID arrives on OnConnectionStateChanged, not as a return pin.
3. Pass that ConnectionID into later select, update, image, and close nodes.
4. Use Get Last Query ID or the QueryID on completed events when you need to match a result back to the UI request that started it.
5. Create a MySQLConnectionOptions asset when you need SSL, timeout, connect attribute, read-only, or multi-result settings editable outside the Blueprint graph.

Closing Connections

• Call CloseConnection with a ConnectionID, or CloseAllConnections, only when you intend to drop the SQL session.
• Leaving a map, streaming a level, or returning to the login map does not close the session.
• The session is closed automatically when the Game Instance shuts down, including quitting the game or stopping Play In Editor.

MySQL Notes

• Use MySQL or MariaDB SQL syntax for queries.
• Keep the stored ConnectionID on Game Instance or a persistent widget if login UI and gameplay maps both need it.
• Image and BLOB Blueprint nodes exist on the MySQL actor. For the shared DataBases package, treat Microsoft SQL Server as the documented image workflow unless your MySQL build exposes those nodes.

Troubleshooting