introduced an index and made sure that the dishes are unique

server/backend/cron/dish_name_download.go

@@ -2,6 +2,7 @@ package cron
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"net/http"
 	"strings"
@@ -95,25 +96,26 @@ func downloadDailyDishes(c *CronService) {
 					CafeteriaID: v.Cafeteria,
 				}
 
-				var count int64
-				var dishId int64
-				if err := c.db.Model(&model.Dish{}).
-					Where("name = ? AND cafeteriaID = ?", dish.Name, dish.CafeteriaID).
-					Select("dish").
-					First(&dishId).
-					Count(&count).Error; err != nil {
-					log.WithError(err).Error("Error while checking whether this is already in database")
-				}
-				if count == 0 {
+				var dbDish model.Dish
+				if err := c.db.First(&dbDish, "name = ? AND cafeteriaID = ?", dish.Name, dish.CafeteriaID).Error; err != nil && errors.Is(err, gorm.ErrRecordNotFound) {
 					if err := c.db.Create(&dish).Error; err != nil {
-						log.WithError(err).Error("Error while creating new CanteenDish entry with name {}. CanteenDish won't be saved", dish.Name)
+						log.WithError(err).WithField("name", dish.Name).Error("Error while creating new CanteenDish entry. CanteenDish won't be saved")
 					}
 					addDishTagsToMapping(dish.Dish, dish.Name, c.db)
-					dishId = dish.Dish
+					dbDish = dish
+				} else if err != nil {
+					log.WithError(err).Error("Error while checking whether the dish is already in database")
 				}
+
+				if dbDish.Type != dish.Type {
+					if err := c.db.Where("dish = ?", dbDish.Dish).Updates(&dish).Error; err != nil {
+						log.WithError(err).WithField("from", dish.Type).WithField("to", dish.Type).Error("Error while updating dish to new type")
+					}
+				}
+
 				if weekliesWereAdded == 0 {
 					errCreate := c.db.Create(&model.DishesOfTheWeek{
-						DishID: dishId,
+						DishID: dbDish.Dish,
 						Year:   int32(year),
 						Week:   int32(week),
 						Day:    int32(weekDayIndex),

server/backend/migration/20240311000000.go

@@ -0,0 +1,20 @@
+package migration
+
+import (
+	"github.com/go-gormigrate/gormigrate/v2"
+	"gorm.io/gorm"
+)
+
+// migrate20240311000000
+// made sure that dishes have the correct indexes
+func migrate20240311000000() *gormigrate.Migration {
+	return &gormigrate.Migration{
+		ID: "20240311000000",
+		Migrate: func(tx *gorm.DB) error {
+			return tx.Raw("create unique index dish_name_cafeteriaID_uindex on dish (name, cafeteriaID)").Error
+		},
+		Rollback: func(tx *gorm.DB) error {
+			return tx.Raw("drop index dish_name_cafeteriaID_uindex on dish").Error
+		},
+	}
+}

server/backend/migration/migration.go

@@ -12,34 +12,7 @@ import (
 
 func autoMigrate(db *gorm.DB) error {
 	err := db.AutoMigrate(
-		&model.Cafeteria{},
-		&model.CafeteriaRating{},
-		&model.CafeteriaRatingTag{},
-		&model.CafeteriaRatingTagOption{},
-		&model.CanteenHeadCount{},
-		&model.Crontab{},
-		&model.Device{},
 		&model.Dish{},
-		&model.DishNameTag{},
-		&model.DishNameTagOption{},
-		&model.DishNameTagOptionExcluded{},
-		&model.DishNameTagOptionIncluded{},
-		&model.DishRating{},
-		&model.DishRatingTag{},
-		&model.DishRatingTagOption{},
-		&model.DishToDishNameTag{},
-		&model.DishesOfTheWeek{},
-		&model.Feedback{},
-		&model.File{},
-		&model.Kino{},
-		&model.NewExamResultsSubscriber{},
-		&model.News{},
-		&model.NewsAlert{},
-		&model.NewsSource{},
-		&model.Notification{},
-		&model.NotificationConfirmation{},
-		&model.NotificationType{},
-		&model.UpdateNote{},
 	)
 	return err
 }
@@ -71,6 +44,7 @@ func manualMigrate(db *gorm.DB) error {
 		migrate20240102000000(),
 		migrate20240103000000(),
 		migrate20240207000000(),
+		migrate20240311000000(),
 	}
 	return gormigrate.New(db, gormigrateOptions, migrations).Migrate()
 }

server/model/dish.go

@@ -14,9 +14,9 @@ var (
 // Dish represents one dish fin a specific cafeteria
 type Dish struct {
 	Dish        int64  `gorm:"primary_key;AUTO_INCREMENT;column:dish;type:int;not null;" json:"dish"`
-	Name        string `gorm:"column:name;type:text;not null;" json:"name" `
+	Name        string `gorm:"column:name;type:text;not null;uniqueIndex:dish_name_cafeteriaID_uindex" json:"name" `
 	Type        string `gorm:"column:type;type:text;not null;" json:"type" `
-	CafeteriaID int64  `gorm:"column:cafeteriaID;foreignKey:cafeteria;type:int;not null;" json:"cafeteriaID"`
+	CafeteriaID int64  `gorm:"column:cafeteriaID;foreignKey:cafeteria;type:int;not null;uniqueIndex:dish_name_cafeteriaID_uindex" json:"cafeteriaID"`
 }
 
 // TableName sets the insert table name for this struct type