Rework SQL statements to actually use PreparedStatements for security reasons

src/de/steamwar/bungeecore/sql/BannedUserIPs.java

@@ -20,7 +20,7 @@ public class BannedUserIPs {
 
     public static List<BannedUserIPs> get(int userID){
         List<BannedUserIPs> userIPs = new ArrayList<>();
-        ResultSet dbentry = SQL.select("SELECT * FROM BannedUserIPs WHERE UserID = '" + userID + "' ORDER BY Timestamp ASC");
+        ResultSet dbentry = SQL.select("SELECT * FROM BannedUserIPs WHERE UserID = ? ORDER BY Timestamp ASC", userID);
         try {
             while(dbentry.next()){
                 userIPs.add(new BannedUserIPs(
@@ -35,7 +35,7 @@ public class BannedUserIPs {
 
     public static List<BannedUserIPs> get(String ip){
         List<BannedUserIPs> userIDs = new ArrayList<>();
-        ResultSet dbentry = SQL.select("SELECT * FROM BannedUserIPs WHERE IP = '" + ip + "' ORDER BY Timestamp DESC");
+        ResultSet dbentry = SQL.select("SELECT * FROM BannedUserIPs WHERE IP = ? ORDER BY Timestamp DESC", ip);
         try {
             while(dbentry.next()){
                 userIDs.add(new BannedUserIPs(
@@ -49,12 +49,7 @@ public class BannedUserIPs {
     }
 
     static void banIP(SteamwarUser user, String ip){
-        SQL.update("INSERT INTO BannedUserIPs\n" +
+        SQL.update("INSERT INTO BannedUserIPs (UserID, Timestamp, IP) VALUES (?, NOW(), ?) ON DUPLICATE KEY UPDATE Timestamp=NOW()", user.getId(), ip);
-                    "  (UserID, Timestamp, IP)\n" +
-                    "VALUES\n" +
-                    "  (" + user.getId() + ", NOW(), '" + ip + "')\n" +
-                    "ON DUPLICATE KEY UPDATE\n" +
-                    " Timestamp=NOW()");
     }
 
     public int getUserID() {

src/de/steamwar/bungeecore/sql/BauweltMember.java

@@ -39,12 +39,8 @@ public class BauweltMember{
     }
 
     private void updateDB(){
-        SQL.update("INSERT INTO BauweltMember" +
+        SQL.update("INSERT INTO BauweltMember (BauweltID, MemberID, Build, WorldEdit, World) VALUES (?, ?, ?, ?, ?) ON DUPLICATE KEY UPDATE Build = VALUES(Build), WorldEdit = VALUES(WorldEdit), World = VALUES(World)",
-                " (BauweltID, MemberID, Build, WorldEdit, World)" +
+                bauweltID, memberID, build, worldEdit, world);
-                " VALUES" +
-                " ('" + bauweltID + "', '" + memberID + "', '" + SQL.booleanToInt(build) + "', '" + SQL.booleanToInt(worldEdit) + "', '" + SQL.booleanToInt(world) + "')" +
-                " ON DUPLICATE KEY UPDATE" +
-                " Build = VALUES(Build), WorldEdit = VALUES(WorldEdit), World = VALUES(World)");
     }
 
     public static BauweltMember getBauMember(UUID ownerID, UUID memberID){
@@ -52,7 +48,7 @@ public class BauweltMember{
     }
 
     public static BauweltMember getBauMember(int ownerID, int memberID){
-        ResultSet member = SQL.select("SELECT * FROM BauweltMember WHERE BauweltID = '" + ownerID + "' AND MemberID = '" + memberID + "'");
+        ResultSet member = SQL.select("SELECT * FROM BauweltMember WHERE BauweltID = ? AND MemberID = ?", ownerID, memberID);
         try {
             if(member == null || !member.next()){
                 return null;
@@ -73,7 +69,7 @@ public class BauweltMember{
 
     public static List<BauweltMember> getMembers(int bauweltID){
         try{
-            ResultSet memberlist = SQL.select("SELECT * FROM BauweltMember WHERE BauweltID = '" + bauweltID + "'");
+            ResultSet memberlist = SQL.select("SELECT * FROM BauweltMember WHERE BauweltID = ?", bauweltID);
             List<BauweltMember> members = new ArrayList<>();
             while(memberlist.next()){
                 int memberID = memberlist.getInt("MemberID");

src/de/steamwar/bungeecore/sql/Event.java

@@ -20,13 +20,13 @@ public class Event {
 
     private static Event current = null;
 
-    private Event(int eventID, String eventName, Timestamp start, Timestamp end, int maximumTeamMembers, boolean publicSchemsOnly){
+    private Event(ResultSet rs) throws SQLException{
-        this.eventID = eventID;
+        this.eventID = rs.getInt("EventID");
-        this.eventName = eventName;
+        this.eventName = rs.getString("EventName");
-        this.start = start;
+        this.start = rs.getTimestamp("Start");
-        this.end = end;
+        this.end = rs.getTimestamp("End");
-        this.maximumTeamMembers = maximumTeamMembers;
+        this.maximumTeamMembers = rs.getInt("MaximumTeamMembers");
-        this.publicSchemsOnly = publicSchemsOnly;
+        this.publicSchemsOnly = rs.getBoolean("PublicSchemsOnly");
     }
 
     public static Event get(){
@@ -40,7 +40,7 @@ public class Event {
                 return null;
             }
 
-            current = new Event(rs.getInt("EventID"), rs.getString("EventName"), rs.getTimestamp("Start"), rs.getTimestamp("End"), rs.getInt("MaximumTeamMembers"), rs.getBoolean("PublicSchemsOnly"));
+            current = new Event(rs);
             return current;
         }catch (SQLException e){
             BungeeCore.log("Failed to load current Event", e);
@@ -54,7 +54,7 @@ public class Event {
             if(!rs.next())
                 throw new IllegalArgumentException();
 
-            return new Event(eventID, rs.getString("EventName"), rs.getTimestamp("Start"), rs.getTimestamp("End"), rs.getInt("MaximumTeamMembers"), rs.getBoolean("PublicSchemsOnly"));
+            return new Event(rs);
         }catch (SQLException e){
             BungeeCore.log("Failed to load Event", e);
             throw new SecurityException();
@@ -62,12 +62,12 @@ public class Event {
     }
 
     public static Event get(String eventName){
-        ResultSet rs = SQL.select("SELECT * FROM Event WHERE lower(EventName) = '" + SQL.disarmString(eventName.toLowerCase()) + "'");
+        ResultSet rs = SQL.select("SELECT * FROM Event WHERE lower(EventName) = ?", eventName.toLowerCase());
         try{
             if(!rs.next())
                 return null;
 
-            return new Event(rs.getInt("EventID"), rs.getString("EventName"), rs.getTimestamp("Start"), rs.getTimestamp("End"), rs.getInt("MaximumTeamMembers"), rs.getBoolean("PublicSchemsOnly"));
+            return new Event(rs);
         }catch (SQLException e){
             BungeeCore.log("Failed to load Event by name", e);
             throw new SecurityException();
@@ -79,7 +79,7 @@ public class Event {
         ResultSet rs = SQL.select("SELECT * FROM Event WHERE Start > now()");
         try{
             while(rs.next())
-                events.add(new Event(rs.getInt("EventID"), rs.getString("EventName"), rs.getTimestamp("Start"), rs.getTimestamp("End"), rs.getInt("MaximumTeamMembers"), rs.getBoolean("PublicSchemsOnly")));
+                events.add(new Event(rs));
         }catch (SQLException e){
             BungeeCore.log("Failed to load Events", e);
         }

src/de/steamwar/bungeecore/sql/EventFight.java

@@ -38,7 +38,7 @@ public class EventFight implements Comparable<EventFight> {
 
     public void reschedule(){
         startTime = Timestamp.from(new Date().toInstant().plus(30, SECONDS));
-        SQL.update("UPDATE EventFight SET StartTime = '" + startTime.toString() + "' WHERE EventID = " + eventID + " AND FightID = " + fightID);
+        SQL.update("UPDATE EventFight SET StartTime = ? WHERE EventID = ? AND FightID = ?", startTime, eventID, fightID);
     }
 
     public static void loadAllComingFights(){
@@ -54,7 +54,7 @@ public class EventFight implements Comparable<EventFight> {
     }
 
     public static List<EventFight> getEvent(int eventID){
-        ResultSet rs = SQL.select("SELECT * FROM EventFight WHERE EventID = " + eventID + " ORDER BY `StartTime` ASC");
+        ResultSet rs = SQL.select("SELECT * FROM EventFight WHERE EventID = ? ORDER BY `StartTime` ASC", eventID);
         List<EventFight> fights = new LinkedList<>();
         try{
             while(rs.next())

src/de/steamwar/bungeecore/sql/Mod.java

@@ -17,8 +17,7 @@ public class Mod {
     }
 
     public static Mod get(String modName, Platform platform){
-        modName = SQL.disarmString(modName);
+        ResultSet rs = SQL.select("SELECT * FROM Mods WHERE ModName = ? AND Platform = ?", modName, platform.value);
-        ResultSet rs = SQL.select("SELECT * FROM Mods WHERE ModName = '" + modName + "' AND Platform = " + platform.value);
         try{
             if(rs.next())
                 return new Mod(modName, platform, ModType.valueOf(rs.getInt("ModType")));
@@ -26,7 +25,7 @@ public class Mod {
             BungeeCore.log("Failed to load Mod", e);
             throw new SecurityException();
         }
-        SQL.update("INSERT INTO Mods (ModName, Platform) VALUES ('" + modName + "'," + platform.value + ")");
+        SQL.update("INSERT INTO Mods (ModName, Platform) VALUES ('" + modName + "'," + platform.value + ")", modName, platform.value);
         return new Mod(modName, platform, ModType.UNKLASSIFIED);
     }
 

src/de/steamwar/bungeecore/sql/PollAnswer.java

@@ -23,7 +23,7 @@ public class PollAnswer {
     }
 
     public static PollAnswer get(int userID){
-        ResultSet rs = SQL.select("SELECT * FROM PollAnswer WHERE UserID = " + userID + " AND Question = '" + PollSystem.getQuestion() + "'");
+    ResultSet rs = SQL.select("SELECT * FROM PollAnswer WHERE UserID = ? AND Question = ?", userID, PollSystem.getQuestion());
         try {
             if(!rs.next())
                 return new PollAnswer(userID, PollSystem.getQuestion());
@@ -40,6 +40,6 @@ public class PollAnswer {
 
     public void setAnswer(int answer){
         this.answer = answer;
-        SQL.update("INSERT INTO PollAnswer (UserID, Question, Answer) VALUES (" + userID + ",'" + question + "'," + answer + ") ON DUPLICATE KEY UPDATE Answer = VALUES(Answer)");
+        SQL.update("INSERT INTO PollAnswer (UserID, Question, Answer) VALUES (?, ?, ?) ON DUPLICATE KEY UPDATE Answer = VALUES(Answer)", userID, question, answer);
     }
 }

src/de/steamwar/bungeecore/sql/SQL.java

@@ -41,60 +41,55 @@ public class SQL {
         }
     }
 
-    private static void sqlException(){
+    static void update(String qry, Object... objects) {
-        close();
+        try {
-        connect(url, weburl, user, password);
+            prepare(con, qry, objects).executeUpdate();
-    }
-
-    static void update(String qry) {
-        try (PreparedStatement st = con.prepareStatement(qry)) {
-            st.executeUpdate();
         } catch (SQLException e) {
             sqlException();
             try (PreparedStatement st = con.prepareStatement(qry)) {
                 st.executeUpdate();
             } catch (SQLException ex) {
-                BungeeCore.log("Could not execute update statement", ex);
+                throw new SecurityException("Could not execute update statement", ex);
             }
         }
     }
 
-    static void webupdate(String qry) {
+    static void webupdate(String qry, Object... objects) {
-        try (PreparedStatement st = webcon.prepareStatement(qry)) {
+        try {
-            st.executeUpdate();
+            prepare(webcon, qry, objects).executeUpdate();
-        } catch (SQLException e) {
-            sqlException();
-            try (PreparedStatement st = webcon.prepareStatement(qry)) {
-                st.executeUpdate();
-            } catch (SQLException ex) {
-                BungeeCore.log("Could not execute update statement", ex);
-            }
-        }
-    }
-
-    static ResultSet select(String qry){
-        try{
-            PreparedStatement st = con.prepareStatement(qry);
-            return st.executeQuery();
         } catch (SQLException e) {
             sqlException();
             try {
-                PreparedStatement st = con.prepareStatement(qry);
+                prepare(webcon, qry, objects).executeUpdate();
-                return st.executeQuery();
+            } catch (SQLException ex) {
+                throw new SecurityException("Could not execute update statement", ex);
+            }
+        }
+    }
+
+    static ResultSet select(String qry, Object... objects){
+        try{
+            return prepare(con, qry, objects).executeQuery();
+        } catch (SQLException e) {
+            sqlException();
+            try {
+                return prepare(con, qry, objects).executeQuery();
             } catch (SQLException ex) {
                 throw new SecurityException("Could not run Select-Statement", ex);
             }
         }
     }
 
-    static String disarmString(String s){
+    private static PreparedStatement prepare(Connection connection, String qry, Object... objects) throws SQLException{
-        return s.replace("'", "");
+        PreparedStatement st = connection.prepareStatement(qry);
+        for(int i = 0; i < objects.length; i++){
+            st.setObject(i+1, objects);
+        }
+        return st;
     }
 
-    static Integer booleanToInt(boolean b){
+    private static void sqlException(){
-        if(b)
+        close();
-            return 1;
+        connect(url, weburl, user, password);
-        else
-            return 0;
     }
 }

src/de/steamwar/bungeecore/sql/Session.java

@@ -14,6 +14,6 @@ public class Session {
     }
 
     public void stopSession(){
-        SQL.update("INSERT INTO Session (UserID, StartTime, EndTime) VALUES ("+ userID + ", '" + startTime.toString() + "', NOW())");
+        SQL.update("INSERT INTO Session (UserID, StartTime, EndTime) VALUES (?, ?, NOW())", userID, startTime);
     }
 }

src/de/steamwar/bungeecore/sql/SteamwarUser.java

@@ -30,7 +30,6 @@ public class SteamwarUser {
     private static final Map<UUID, SteamwarUser> usersByUUID = new HashMap<>();
     private static final Map<Integer, SteamwarUser> usersById = new HashMap<>();
     private static final Timestamp PERMA_BAN = Timestamp.from(Instant.ofEpochSecond(946684800));
-    private static final String SELECT_UUID = "SELECT * FROM UserData WHERE UUID = '";
 
     private SteamwarUser(ResultSet rs) throws SQLException {
         id = rs.getInt("id");
@@ -51,14 +50,14 @@ public class SteamwarUser {
         SteamwarUser user = SteamwarUser.get(connection.getUniqueId());
 
         if(user != null){
-            String userName = SQL.disarmString(connection.getName());
+            String userName = connection.getName();
             if(!user.userName.equals(userName)){
-                SQL.update("UPDATE UserData SET UserName = '" + userName + "' WHERE id = " + user.id);
+                SQL.update("UPDATE UserData SET UserName = ? WHERE id = ?", userName, user.id);
                 user.userName = userName;
             }
         }else{
-            SQL.update("INSERT INTO UserData (UUID, UserName, UserGroup) VALUES ('" + connection.getUniqueId() + "', '" + connection.getName() + "', 'Member')");
+            SQL.update("INSERT INTO UserData (UUID, UserName, UserGroup) VALUES (?, ?, 'Member')", connection.getUniqueId().toString(), connection.getName());
-            user = dbInit(SQL.select(SELECT_UUID + connection.getUniqueId().toString() + "'"));
+            user = dbInit(SQL.select("SELECT * FROM UserData WHERE UUID = ?", connection.getUniqueId()));
             if(user == null)
                 throw new SecurityException("user == null");
         }
@@ -67,16 +66,16 @@ public class SteamwarUser {
     }
 
     public static SteamwarUser get(String userName){
-        userName = SQL.disarmString(userName).toLowerCase();
+        userName = userName.toLowerCase();
         if(usersByName.containsKey(userName))
             return usersByName.get(userName);
-        return dbInit(SQL.select("SELECT * FROM UserData WHERE lower(UserName) = '" + userName + "'"));
+        return dbInit(SQL.select("SELECT * FROM UserData WHERE lower(UserName) = ?", userName));
     }
 
     public static SteamwarUser get(UUID uuid){
         if(usersByUUID.containsKey(uuid))
             return usersByUUID.get(uuid);
-        return dbInit(SQL.select(SELECT_UUID + uuid.toString() + "'"));
+        return dbInit(SQL.select("SELECT * FROM UserData WHERE UUID = ?", uuid.toString()));
     }
 
     public static SteamwarUser get(ProxiedPlayer player){
@@ -86,7 +85,7 @@ public class SteamwarUser {
     public static SteamwarUser get(int id){
         if(usersById.containsKey(id))
             return usersById.get(id);
-        return dbInit(SQL.select("SELECT * FROM UserData WHERE id = " + id));
+        return dbInit(SQL.select("SELECT * FROM UserData WHERE id = ?", id));
     }
 
     public static void clearCache(){
@@ -96,17 +95,12 @@ public class SteamwarUser {
     }
 
     public void setWebpw(String password){
-        SQL.webupdate("INSERT INTO User\n" +
+        SQL.webupdate("INSERT INTO User (UID, WebPassword) VALUES (?, password(?)) ON DUPLICATE KEY UPDATE WebPassword = VALUES(WebPassword)", id, password);
-                "  (UID, WebPassword)\n" +
-                "VALUES\n" +
-                "  (" + id + ", password('"+ SQL.disarmString(password) + "'))\n" +
-                "ON DUPLICATE KEY UPDATE\n" +
-                "  WebPassword = VALUES(WebPassword)");
     }
 
     public void setTeam(int team){
         this.team = team;
-        SQL.update("Update UserData SET Team = " + team + " WHERE id = " + id);
+        SQL.update("Update UserData SET Team = ? WHERE id = ?", team, id);
     }
 
     public int getId() {
@@ -135,8 +129,8 @@ public class SteamwarUser {
         } else if (banTime.after(new Date()) || banTime.before(PERMA_BAN)) {
             return true;
         } else {
-            SQL.update("UPDATE UserData SET BanTime = NULL, BanReason = '' WHERE id = " + id);
+            SQL.update("UPDATE UserData SET BanTime = NULL, BanReason = '' WHERE id = ?", id);
-            SQL.update("DELETE FROM BannedUserIPs WHERE UserID = '" + getId() + "'");
+            SQL.update("DELETE FROM BannedUserIPs WHERE UserID = ?", id);
             banTime = null;
             banReason = "";
             return false;
@@ -149,7 +143,7 @@ public class SteamwarUser {
         }else if(muteTime.after(new Date()) || muteTime.before(PERMA_BAN)){
             return true;
         }else{
-            SQL.update("UPDATE UserData SET MuteTime = NULL, MuteReason = '' WHERE id = " + id);
+            SQL.update("UPDATE UserData SET MuteTime = NULL, MuteReason = '' WHERE id = ?", id);
             muteTime = null;
             muteReason = "";
             return false;
@@ -179,7 +173,7 @@ public class SteamwarUser {
     }
 
     public void ban(Timestamp time, String banReason){
-        SQL.update("UPDATE UserData SET BanTime = '" + time.toString() + "', BanReason = '" + banReason + "' WHERE id = " + id);
+        SQL.update("UPDATE UserData SET BanTime = ?, BanReason = ? WHERE id = ?", time, banReason, id);
         banTime = time;
         this.banReason = banReason;
 
@@ -192,7 +186,7 @@ public class SteamwarUser {
     }
 
     public void mute(Timestamp time, String muteReason){
-        SQL.update("UPDATE UserData SET MuteTime = '" + time.toString() + "', MuteReason = '" + muteReason + "' WHERE id = " + id);
+        SQL.update("UPDATE UserData SET MuteTime = ?, MuteReason = ? WHERE id = ?", time, muteReason, id);
         muteTime = time;
         this.muteReason = muteReason;
     }

src/de/steamwar/bungeecore/sql/Team.java

@@ -32,10 +32,7 @@ public class Team {
     }
 
     public static void create(String kuerzel, String name, int leader){
-        SQL.update("INSERT INTO Team" +
+        SQL.update("INSERT INTO Team (TeamKuerzel, TeamName, TeamLeader) VALUES (?, ?, ?)", kuerzel, name, leader);
-                " (TeamKuerzel, TeamName, TeamLeader)" +
-                " VALUES" +
-                " ('" + kuerzel + "', '" + name + "', '" + leader + "')");
     }
 
     public static Team get(int id){
@@ -46,7 +43,7 @@ public class Team {
         for(Team team : teamCache)
             if(team.teamId == id)
                 return team;
-        return load(select("SELECT * FROM Team WHERE TeamID = " + id));
+        return load(select("SELECT * FROM Team WHERE TeamID = ?", id));
     }
 
     public static Team get(String name){
@@ -56,7 +53,7 @@ public class Team {
         for(Team team : teamCache)
             if(team.teamKuerzel.equalsIgnoreCase(name))
                 return team;
-        return load(select("SELECT * FROM Team WHERE (lower(TeamName) = '" + SQL.disarmString(name).toLowerCase() + "' OR lower(TeamKuerzel) = '" + SQL.disarmString(name).toLowerCase() + "') AND NOT TeamDeleted"));
+        return load(select("SELECT * FROM Team WHERE (lower(TeamName) = ? OR lower(TeamKuerzel) = ?) AND NOT TeamDeleted", name.toLowerCase(), name.toLowerCase()));
     }
 
     public static List<Team> getAll(){
@@ -90,12 +87,7 @@ public class Team {
     }
 
     private void updateDB(){
-        SQL.update("INSERT INTO Team" +
+        SQL.update("INSERT INTO Team (TeamID, TeamKuerzel, TeamName, TeamLeader) VALUES (?, ?, ?, ?) ON DUPLICATE KEY UPDATE TeamName = VALUES(TeamName), TeamKuerzel = VALUES(TeamKuerzel), TeamLeader = VALUES(TeamLeader)", teamId, teamKuerzel, teamName, teamLeader);
-                " (TeamID, TeamKuerzel, TeamName, TeamLeader)" +
-                " VALUES" +
-                " ('" + teamId + "', '" + teamKuerzel + "', '" + teamName + "', '" + teamLeader + "')" +
-                " ON DUPLICATE KEY UPDATE" +
-                " TeamName = VALUES(TeamName), TeamKuerzel = VALUES(TeamKuerzel), TeamLeader = VALUES(TeamLeader)");
     }
 
     public int getTeamId() {
@@ -107,7 +99,7 @@ public class Team {
     }
 
     public void setTeamKuerzel(String teamKuerzel) {
-        this.teamKuerzel = SQL.disarmString(teamKuerzel);
+        this.teamKuerzel = teamKuerzel;
         updateDB();
     }
 
@@ -116,7 +108,7 @@ public class Team {
     }
 
     public void setTeamName(String teamName) {
-        this.teamName = SQL.disarmString(teamName);
+        this.teamName = teamName;
         updateDB();
     }
 
@@ -130,7 +122,7 @@ public class Team {
     }
 
     public int size(){
-        ResultSet rs = select("SELECT COUNT(id) FROM UserData WHERE Team = " + teamId);
+        ResultSet rs = select("SELECT COUNT(id) FROM UserData WHERE Team = ?", teamId);
         try {
             rs.next();
             return rs.getInt("COUNT(id)");
@@ -141,13 +133,13 @@ public class Team {
     }
 
     public void disband(){
-        SQL.update("UPDATE Team SET TeamDeleted = 1, TeamLeader = NULL WHERE TeamID = " + teamId);
+        SQL.update("UPDATE Team SET TeamDeleted = 1, TeamLeader = NULL WHERE TeamID = ?", teamId);
         teamCache.remove(this);
     }
 
     public List<Integer> getMembers(){
         try{
-            ResultSet memberlist = select("SELECT id FROM UserData WHERE Team = '" + teamId + "'");
+            ResultSet memberlist = select("SELECT id FROM UserData WHERE Team = ?", teamId);
             List<Integer> members = new ArrayList<>();
             while(memberlist.next()){
                 members.add(memberlist.getInt("id"));

src/de/steamwar/bungeecore/sql/TeamTeilnahme.java

@@ -11,15 +11,15 @@ public class TeamTeilnahme {
     private TeamTeilnahme(){}
 
     public static void teilnehmen(int teamID, int eventID){
-        SQL.update("INSERT INTO TeamTeilnahme (TeamID, EventID) VALUES (" + teamID + "," + eventID + ")");
+        SQL.update("INSERT INTO TeamTeilnahme (TeamID, EventID) VALUES (?, ?)", teamID, eventID);
     }
 
     public static void notTeilnehmen(int teamID, int eventID){
-        SQL.update("DELETE FROM TeamTeilnahme WHERE TeamID = " + teamID + " AND EventID = " + eventID);
+        SQL.update("DELETE FROM TeamTeilnahme WHERE TeamID = ? AND EventID = ?", teamID, eventID);
     }
 
     public static boolean nimmtTeil(int teamID, int eventID){
-        ResultSet rs = SQL.select("SELECT * FROM TeamTeilnahme WHERE TeamID = " + teamID + " AND EventID = " + eventID);
+        ResultSet rs = SQL.select("SELECT * FROM TeamTeilnahme WHERE TeamID = ? AND EventID = ?", teamID, eventID);
         try{
             return rs.next();
         }catch (SQLException e){
@@ -30,7 +30,7 @@ public class TeamTeilnahme {
 
     public static Set<Team> getTeams(int eventID){
         Set<Team> teams = new HashSet<>();
-        ResultSet rs = SQL.select("SELECT * FROM TeamTeilnahme WHERE EventID = " + eventID);
+        ResultSet rs = SQL.select("SELECT * FROM TeamTeilnahme WHERE EventID = ?", eventID);
         try{
             while(rs.next())
                 teams.add(Team.get(rs.getInt("TeamID")));
@@ -42,7 +42,7 @@ public class TeamTeilnahme {
 
     public static Set<Event> getEvents(int teamID){
         Set<Event> events = new HashSet<>();
-        ResultSet rs = SQL.select("SELECT * FROM TeamTeilnahme WHERE TeamID = " + teamID);
+        ResultSet rs = SQL.select("SELECT * FROM TeamTeilnahme WHERE TeamID = ?", teamID);
         try{
             while(rs.next())
                 events.add(Event.get(rs.getInt("EventID")));