Migrating the databse

app/src/main/java/krusty/Database.java

@@ -3,32 +3,27 @@ package krusty;
 import spark.Request;
 import spark.Response;
 
+// Likely dependencies for db operations
 import java.sql.Connection;
 import java.sql.DriverManager;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
+
+// Likely dependencies for general operations
+import java.io.File;
+import java.util.StringJoiner;
+import java.io.IOException;
+import java.io.FileNotFoundException;
+import java.util.Scanner;
 
 public class Database {
-	private static final String jdbcString = "jdbc:sqlite:krusty.sqlite3";
-
-	public void connect() {
-		Connection conn = null;
-
-		try {
-			conn = DriverManager.getConnection(jdbcString);
-			System.out.println("Connection to SQLite has been established.");
-		} catch (Exception e) {
-			System.out.println(e.getMessage());
-		} finally {
-			try {
-				if (conn != null) {
-					conn.close();
-				}
-			} catch (Exception e) {
-				System.out.println(e.getMessage());
-			}
-		}
-	}
-
-	// TODO: Implement and change output in all methods below!
+	// Here, we use an in-memory database. This string could be changed to
+	// "jdbc:sqlite:<filename>.sqlite3" to use a file-based database instead.
+	// Nore that ":memory:" is an **SQLite specific** magic string that tells the
+	// underlying SQLite engine to store the database in memory.
+	private static final String jdbcString = "jdbc:sqlite::memory:"; 
+	private Connection conn = null;
 
 	public String getCustomers(Request req, Response res) {
 		return "{}";
@@ -57,4 +52,52 @@ public class Database {
 	public String createPallet(Request req, Response res) {
 		return "{}";
 	}
+
+	/** Connects to the database using the configured jdbcString. */
+	public void connect() {
+		try {
+			conn = DriverManager.getConnection(jdbcString);
+		} catch (Exception e) {
+			System.out.println(e.getMessage());
+		} finally {
+			System.out.println("Connection to SQLite has been established.");
+		}
+	}
+
+	// The script location is relative to the gradle 
+	// build script ("build.gradle.kts", in this case).
+	/** Reads an sql script into the database */
+	public void migrateScript(String filename) {
+		// Open the file
+		StringBuilder script = new StringBuilder();
+		try {
+			File myObj = new File(filename);
+			Scanner myReader = new Scanner(myObj);
+
+			while (myReader.hasNextLine()) {
+				String data = myReader.nextLine();
+				script.append(data);
+			}
+			myReader.close();
+		} catch (FileNotFoundException e) {
+			System.out.println("Migration script not found...");
+			e.printStackTrace();
+		} finally {
+			System.out.println("Migration script read successfully...");
+		}
+
+		// Execute the script
+		try {
+			conn.setAutoCommit(false);
+			Statement stmt = conn.createStatement();
+			stmt.execute(script.toString());
+			conn.commit();
+			conn.setAutoCommit(true);
+		} catch (SQLException e) {
+			System.out.println("Error executing migration script...");
+			e.printStackTrace();
+		} finally {
+			System.out.println("Migration script executed successfully...");
+		}
+	}
 }

app/src/main/java/krusty/ServerMain.java

@@ -18,6 +18,9 @@ public class ServerMain {
 		db = new Database();
 		db.connect();
 
+		// Here, we can migrate an arbitrary number of SQL scripts.
+		db.migrateScript("CrustyCookies/Migrations/0010_users.sql");
+
 		port(PORT);
 		
 		enableCORS();