Game Development
Save game schema
Learn save schema design and versioning.
Save Data Model and Version Tracking
As games evolve, new fields are added to the save data model or old fields are removed. To ensure older save files remain intact across updates, a saveVersion number should always be included in the model.
[System.Serializable]
public class GameSaveData {
public int saveVersion = 2; // Version tracking number
public int playerLevel;
public float playTime;
}
This field immediately identifies which game release generated the save file when opened.
Data Migration Strategy
When the file's saveVersion is lower than the current build, migration logic runs. Newly added fields are populated with defaults, keeping the player's past accomplishments intact.
if (data.saveVersion < 2) {
// Upgrade from version 1 to 2:
// Initialize new features with defaults
data.saveVersion = 2;
}
This ensures players never have to wipe their progression when downloading a new patch.
Exercise Version check and data model
Define a Start method. Inside, declare int saveVersion = 2; and print "Kayit veri surumu: " + saveVersion to the console.
Show example solution
using UnityEngine;
public class VersionManager : MonoBehaviour
{
void Start()
{
int saveVersion = 2;
Debug.Log("Kayit veri surumu: " + saveVersion);
}
}
Test yourself
-
Which information should be retained in the save object to maintain backward compatibility and prevent corrupt saves across updates?
- Version number
- Monitor refresh rate (Hz)
- GPU core temperature
- Serial number of the hard drive where game is installed
Show answer
Version number — A version number stored inside save data allows safe detection and migration of data from earlier game versions.
-
Version check
if (saveData.____ < 2) { MigrateToVersion2(saveData); }
Show answer
if (saveData.saveVersion < 2) { MigrateToVersion2(saveData); }
-
Versioning concepts
- saveVersion
- Version number of the save file
- Migration
- Upgrading old saves to the new format
- Backward Compatibility
- Backward compatibility support
- Default Value
- Default assigned to newly added fields
Next lesson: Summary - Save/Load
