Fix: Create Schema Migration

Einheit_1/2025_5BHITN_Konstantin_Hintermayer_create_schema.sql

@@ -1,18 +1,14 @@
-CREATE DATABASE "2025_5bhitn_konstantin_hintermayer_smarter_rentDB";
+IF NOT EXISTS (SELECT name FROM sys.databases WHERE name = '2025_5bhitn_konstantin_hintermayer_smarter_rentDB')
-GO
+BEGIN
-USE "2025_5bhitn_konstantin_hintermayer_smarter_rentDB";
+    CREATE DATABASE [2025_5bhitn_konstantin_hintermayer_smarter_rentDB];
+END;
 GO
 
-DROP TABLE IF EXISTS Rental;
+USE [2025_5bhitn_konstantin_hintermayer_smarter_rentDB];
-
+GO
-DROP TABLE IF EXISTS Customer;
-
-DROP TABLE IF EXISTS [Location];
-
-DROP TABLE IF EXISTS Vehicle;
-
-DROP TABLE IF EXISTS VehicleCategory;
 
+IF NOT EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[Customer]') AND type = 'U')
+BEGIN
     CREATE TABLE Customer (
         id BIGINT NOT NULL IDENTITY (1, 1),
         [name] VARCHAR(50) NOT NULL,
@@ -20,14 +16,20 @@ CREATE TABLE Customer (
         driverlicenseid VARCHAR(100) NOT NULL,
         PRIMARY KEY (id)
     );
+END;
 
+IF NOT EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[Location]') AND type = 'U')
+BEGIN
     CREATE TABLE Location (
         id BIGINT NOT NULL IDENTITY (1, 1),
         [name] VARCHAR(250) NOT NULL,
         [address] VARCHAR(250) NOT NULL,
         PRIMARY KEY (id)
     );
+END;
 
+IF NOT EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[Rental]') AND type = 'U')
+BEGIN
     CREATE TABLE Rental (
         id BIGINT NOT NULL IDENTITY (1, 1),
         rentalStart DATETIME NOT NULL,
@@ -38,6 +40,16 @@ CREATE TABLE Rental (
         PRIMARY KEY (id)
     );
 
+
+    ALTER TABLE Rental
+    ADD CONSTRAINT FK_Customer_TO_Rental FOREIGN KEY (customerID) REFERENCES Customer (id);
+
+    ALTER TABLE Rental
+    ADD CONSTRAINT FK_Vehicle_TO_Rental FOREIGN KEY (vehicleID) REFERENCES Vehicle (id);
+END;
+
+IF NOT EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[Vehicle]') AND type = 'U')
+BEGIN
     CREATE TABLE Vehicle (
         id BIGINT NOT NULL IDENTITY (1, 1),
         brand VARCHAR(50) NOT NULL,
@@ -49,21 +61,20 @@ CREATE TABLE Vehicle (
         PRIMARY KEY (id)
     );
 
+    ALTER TABLE Vehicle
+    ADD CONSTRAINT FK_Location_TO_Vehicle FOREIGN KEY (locationID) REFERENCES Location (id);
+
+    ALTER TABLE Vehicle
+    ADD CONSTRAINT FK_VehicleCategory_TO_Vehicle FOREIGN KEY (vehicleCategoryID) REFERENCES VehicleCategory (id);
+END;
+
+IF NOT EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[VehicleCategory]') AND type = 'U')
+BEGIN
     CREATE TABLE VehicleCategory (
         id BIGINT NOT NULL IDENTITY (1, 1),
         [description] VARCHAR(250) NOT NULL,
         pricePerDay DECIMAL NOT NULL,
         PRIMARY KEY (id)
     );
+END;
 
-ALTER TABLE Rental
-ADD CONSTRAINT FK_Customer_TO_Rental FOREIGN KEY (customerID) REFERENCES Customer (id);
-
-ALTER TABLE Rental
-ADD CONSTRAINT FK_Vehicle_TO_Rental FOREIGN KEY (vehicleID) REFERENCES Vehicle (id);
-
-ALTER TABLE Vehicle
-ADD CONSTRAINT FK_Location_TO_Vehicle FOREIGN KEY (locationID) REFERENCES Location (id);
-
-ALTER TABLE Vehicle
-ADD CONSTRAINT FK_VehicleCategory_TO_Vehicle FOREIGN KEY (vehicleCategoryID) REFERENCES VehicleCategory (id);