diff --git a/common/database.go b/common/database.go
index 6cdfb98..3c9fae3 100644
--- a/common/database.go
+++ b/common/database.go
@@ -138,13 +138,13 @@ func DummyPopulateDB(test_db *gorm.DB) {
 	test_db.Model(&simn_A).Association("Projects").Append(&proj_B)
 
 	test_db.Model(&proj_A).Association("Simulation").Append(&simn_A)
-	test_db.Debug().Model(&proj_A).Association("User").Append(&usr_A)
+	test_db.Model(&proj_A).Association("User").Append(&usr_A)
 	test_db.Model(&proj_A).Association("Visualizations").Append(&vis_A)
 	test_db.Model(&proj_A).Association("Visualizations").Append(&vis_B)
 
 	test_db.Model(&usr_A).Association("Projects").Append(&proj_A)
 	test_db.Model(&usr_A).Association("Projects").Append(&proj_B)
-	test_db.Debug().Model(&usr_A).Association("Simulations").Append(&simn_A)
+	test_db.Model(&usr_A).Association("Simulations").Append(&simn_A)
 	test_db.Model(&usr_A).Association("Simulations").Append(&simn_B)
 	test_db.Model(&usr_A).Association("Files").Append(&file_A)
 	test_db.Model(&usr_A).Association("Files").Append(&file_B)
diff --git a/common/datastructs.go b/common/datastructs.go
index e9f4b5e..3a49ac2 100644
--- a/common/datastructs.go
+++ b/common/datastructs.go
@@ -26,66 +26,80 @@ type File struct {
 	Size        uint   `gorm:"not null"`
 	ImageHeight uint   // only required in case file is an image
 	ImageWidth  uint   // only required in case file is an image
-	User        User   `gorm:"not null"`
-	UserID      uint   `gorm:"not null"`
 	Date        time.Time
+
+	User   User `gorm:"not null;association_autoupdate:false"`
+	UserID uint `gorm:"not null"`
 }
 
 type Project struct {
 	gorm.Model
-	Name           string     `gorm:"not null"`
-	User           User       `gorm:"not null"`
-	UserID         uint       `gorm:"not null"`
-	Simulation     Simulation `gorm:"not null"`
-	SimulationID   uint       `gorm:"not null"`
-	Visualizations []Visualization
+	Name string `gorm:"not null"`
+
+	User   User `gorm:"not null;association_autoupdate:false"`
+	UserID uint `gorm:"not null"`
+
+	Simulation   Simulation `gorm:"not null;association_autoupdate:false"`
+	SimulationID uint       `gorm:"not null"`
+
+	Visualizations []Visualization `gorm:"association_autoupdate:false"`
 }
 
 type Simulation struct {
 	gorm.Model
-	Name            string            `gorm:"not null"`
-	Running         bool              `gorm:"default:false"`
-	User            User              `gorm:"not null"`
-	UserID          uint              `gorm:"not null"`
-	StartParameters postgres.Jsonb    // TODO default value
-	Models          []SimulationModel `gorm:"foreignkey:BelongsToSimulationID"`
-	Projects        []Project
+	Name            string         `gorm:"not null"`
+	Running         bool           `gorm:"default:false"`
+	StartParameters postgres.Jsonb // TODO default value
+
+	User   User `gorm:"not null;association_autoupdate:false"`
+	UserID uint `gorm:"not null"`
+
+	Models   []SimulationModel `gorm:"foreignkey:BelongsToSimulationID;association_autoupdate:false"`
+	Projects []Project         `gorm:"association_autoupdate:false"`
 }
 
 type SimulationModel struct {
 	gorm.Model
-	Name                  string         `gorm:"not null"`
-	OutputLength          int            `gorm:"default:1"`
-	InputLength           int            `gorm:"default:1"`
-	OutputMapping         []Signal       // order of signals is important
-	InputMapping          []Signal       // order of signals is important
-	StartParameters       postgres.Jsonb // TODO: default value?
-	BelongsToSimulation   Simulation     `gorm:"not null"`
-	BelongsToSimulationID uint           `gorm:"not null"`
-	BelongsToSimulator    Simulator      `gorm:"not null"`
-	BelongsToSimulatorID  uint           `gorm:"not null"`
+	Name            string         `gorm:"not null"`
+	OutputLength    int            `gorm:"default:1"`
+	InputLength     int            `gorm:"default:1"`
+	StartParameters postgres.Jsonb // TODO: default value?
+
+	BelongsToSimulation   Simulation `gorm:"not null;association_autoupdate:false"`
+	BelongsToSimulationID uint       `gorm:"not null"`
+
+	BelongsToSimulator   Simulator `gorm:"not null;association_autoupdate:false"`
+	BelongsToSimulatorID uint      `gorm:"not null"`
+
+	// NOTE: order of signals is important
+	OutputMapping []Signal `gorm:"association_autoupdate:false"`
+	InputMapping  []Signal `gorm:"association_autoupdate:false"`
 }
 
 type User struct {
 	gorm.Model
-	Username    string `gorm:"unique;not null"`
-	Password    string `gorm:"not null"`
-	Mail        string `gorm:"default:''"`
-	Role        string `gorm:"default:'user'"`
-	Projects    []Project
-	Simulations []Simulation
-	Files       []File
+	Username string `gorm:"unique;not null"`
+	Password string `gorm:"not null"`
+	Mail     string `gorm:"default:''"`
+	Role     string `gorm:"default:'user'"`
+
+	Projects    []Project    `gorm:"association_autoupdate:false"`
+	Simulations []Simulation `gorm:"association_autoupdate:false"`
+	Files       []File       `gorm:"association_autoupdate:false"`
 }
 
 type Visualization struct {
 	gorm.Model
-	Name      string  `gorm:"not null"`
-	Project   Project `gorm:"not null"`
+	Name string `gorm:"not null"`
+	Grid int    `gorm:"default:15"`
+
+	Project   Project `gorm:"not null;association_autoupdate:false"`
 	ProjectID uint    `gorm:"not null"`
-	Grid      int     `gorm:"default:15"`
-	User      User    `gorm:"not null"`
-	UserID    uint    `gorm:"not null"`
-	Widgets   []Widget
+
+	User   User `gorm:"not null;association_autoupdate:false"`
+	UserID uint `gorm:"not null"`
+
+	Widgets []Widget `gorm:"association_autoupdate:false"`
 }
 
 type Signal struct {