Update() public method

Builds an UPDATE query.
public Update ( string table, string columns, string parameters ) : string
table string The table.
columns string The columns to update.
parameters string The parameters.
return string
Beispiel #1
0
        public override void RenameFile(string from, string to)
        {
            ICommandBuilder builder     = _sqlStorageProviderUtility.GetCommandBuilder2();
            DbConnection    connection  = builder.GetConnection(_connString);
            DbTransaction   transaction = _sqlStorageProviderUtility.BeginTransaction(connection);

            QueryBuilder queryBuilder = new QueryBuilder(builder);

            if (!FileExists(transaction, from))
            {
                _sqlStorageProviderUtility.RollbackTransaction(transaction);
                throw new ArgumentException("File does not exist", "from");
            }
            if (FileExists(transaction, to))
            {
                _sqlStorageProviderUtility.RollbackTransaction(transaction);
                throw new ArgumentException("File already exists", "to");
            }

            string query = queryBuilder.Update("SearchIndex", new string[] { "Name" }, new string[] { "NewName" });

            query = queryBuilder.Where(query, "Wiki", WhereOperator.Equals, "Wiki");
            query = queryBuilder.AndWhere(query, "Name", WhereOperator.Equals, "OldName");

            List <Parameter> parameters = new List <Parameter>(3);

            parameters.Add(new Parameter(ParameterType.String, "Wiki", _wiki));
            parameters.Add(new Parameter(ParameterType.String, "NewName", to));
            parameters.Add(new Parameter(ParameterType.String, "OldName", from));

            DbCommand command = builder.GetCommand(transaction, query, parameters);

            int rows = _sqlStorageProviderUtility.ExecuteNonQuery(command, false);

            if (rows != 1)
            {
                _sqlStorageProviderUtility.RollbackTransaction(transaction);
            }
            else
            {
                _sqlStorageProviderUtility.CommitTransaction(transaction);

                // we delete and force a redownload, since we can't do this in an atomic way
                if (_cacheDirectory.FileExists(from))
                {
                    _cacheDirectory.DeleteFile(from);
                }

                // drop old cached data as it's wrong now
                if (_cacheDirectory.FileExists(from + ".blob"))
                {
                    _cacheDirectory.DeleteFile(from + ".blob");
                }
            }
        }
        /// <summary>
        /// Renames or moves a File.
        /// </summary>
        /// <param name="oldFullName">The old full name of the File.</param>
        /// <param name="newFullName">The new full name of the File.</param>
        /// <returns><c>true</c> if the File is renamed, <c>false</c> otherwise.</returns>
        /// <exception cref="ArgumentNullException">If <paramref name="oldFullName"/> or <paramref name="newFullName"/> are <c>null</c>.</exception>
        /// <exception cref="ArgumentException">If <paramref name="oldFullName"/> or <paramref name="newFullName"/> are empty, or if the old file does not exist, or if the new file already exist.</exception>
        public bool RenameFile(string oldFullName, string newFullName)
        {
            if(oldFullName == null) throw new ArgumentNullException("oldFullName");
            if(oldFullName.Length == 0) throw new ArgumentException("Old Full Name cannot be empty", "oldFullName");
            if(newFullName == null) throw new ArgumentNullException("newFullName");
            if(newFullName.Length == 0) throw new ArgumentException("New Full Name cannot be empty", "newFullName");

            ICommandBuilder builder = GetCommandBuilder();
            DbConnection connection = builder.GetConnection(connString);
            DbTransaction transaction = BeginTransaction(connection);

            QueryBuilder queryBuilder = new QueryBuilder(builder);

            if(!FileExists(transaction, oldFullName)) {
                RollbackTransaction(transaction);
                throw new ArgumentException("File does not exist", "oldFullName");
            }
            if(FileExists(transaction, newFullName)) {
                RollbackTransaction(transaction);
                throw new ArgumentException("File already exists", "newFullPath");
            }

            string oldDirectory, newDirectory, oldFilename, newFilename;
            SplitFileFullName(oldFullName, out oldDirectory, out oldFilename);
            SplitFileFullName(newFullName, out newDirectory, out newFilename);

            string query = queryBuilder.Update("File", new string[] { "Name" }, new string[] { "NewName" });
            query = queryBuilder.Where(query, "Name", WhereOperator.Equals, "OldName");
            query = queryBuilder.AndWhere(query, "Directory", WhereOperator.Equals, "OldDirectory");

            List<Parameter> parameters = new List<Parameter>(3);
            parameters.Add(new Parameter(ParameterType.String, "NewName", newFilename));
            parameters.Add(new Parameter(ParameterType.String, "OldName", oldFilename));
            parameters.Add(new Parameter(ParameterType.String, "OldDirectory", oldDirectory));

            DbCommand command = builder.GetCommand(transaction, query, parameters);

            int rows = ExecuteNonQuery(command, false);
            if(rows == 1) CommitTransaction(transaction);
            else RollbackTransaction(transaction);

            return rows == 1;
        }
        /// <summary>
        /// Notifies the Provider that a Page has been renamed.
        /// </summary>
        /// <param name="oldPage">The old Page Info object.</param>
        /// <param name="newPage">The new Page Info object.</param>
        /// <exception cref="ArgumentNullException">If <paramref name="oldPage"/> or <paramref name="newPage"/> are <c>null</c>.</exception>
        /// <exception cref="ArgumentException">If the new page is already in use.</exception>
        public void NotifyPageRenaming(PageInfo oldPage, PageInfo newPage)
        {
            if(oldPage == null) throw new ArgumentNullException("oldPage");
            if(newPage == null) throw new ArgumentNullException("newPage");

            ICommandBuilder builder = GetCommandBuilder();
            DbConnection connection = builder.GetConnection(connString);
            DbTransaction transaction = BeginTransaction(connection);

            if(ListPageAttachments(transaction, newPage).Length > 0) {
                RollbackTransaction(transaction);
                throw new ArgumentException("New Page already exists", "newPage");
            }

            QueryBuilder queryBuilder = new QueryBuilder(builder);

            string query = queryBuilder.Update("Attachment", new string[] { "Page" }, new string[] { "NewPage" });
            query = queryBuilder.Where(query, "Page", WhereOperator.Equals, "OldPage");

            List<Parameter> parameters = new List<Parameter>(2);
            parameters.Add(new Parameter(ParameterType.String, "NewPage", newPage.FullName));
            parameters.Add(new Parameter(ParameterType.String, "OldPage", oldPage.FullName));

            DbCommand command = builder.GetCommand(transaction, query, parameters);

            int rows = ExecuteNonQuery(command, false);

            if(rows != -1) CommitTransaction(transaction);
            else RollbackTransaction(transaction);
        }
        /// <summary>
        /// Renames or moves a Directory.
        /// </summary>
        /// <param name="transaction">The current transaction to use.</param>
        /// <param name="oldFullPath">The old full path of the Directory.</param>
        /// <param name="newFullPath">The new full path of the Directory.</param>
        /// <returns><c>true</c> if the Directory is renamed, <c>false</c> otherwise.</returns>
        private bool RenameDirectory(DbTransaction transaction, string oldFullPath, string newFullPath)
        {
            string[] directories = ListDirectories(transaction, oldFullPath);
            foreach(string dir in directories) {
                string trimmed = dir.Trim('/');
                string name = trimmed.Substring(trimmed.LastIndexOf("/") + 1);

                string newFullPathSub = PrepareDirectory(newFullPath + name);

                RenameDirectory(dir, newFullPathSub);
            }

            ICommandBuilder builder = GetCommandBuilder();
            QueryBuilder queryBuilder = new QueryBuilder(builder);

            string query = queryBuilder.Update("Directory", new string[] { "FullPath" }, new string[] { "NewDirectory1" });
            query = queryBuilder.Where(query, "FullPath", WhereOperator.Equals, "OldDirectory1");

            List<Parameter> parameters = new List<Parameter>(2);
            parameters.Add(new Parameter(ParameterType.String, "NewDirectory1", newFullPath));
            parameters.Add(new Parameter(ParameterType.String, "OldDirectory1", oldFullPath));

            DbCommand command = builder.GetCommand(transaction, query, parameters);

            int rows = ExecuteNonQuery(command, false);

            return rows > 0;
        }
        /// <summary>
        /// Removes a Message.
        /// </summary>
        /// <param name="transaction">A database transaction.</param>
        /// <param name="page">The Page.</param>
        /// <param name="id">The ID of the Message to remove.</param>
        /// <param name="removeReplies">A value specifying whether or not to remove the replies.</param>
        /// <returns>True if the Message is removed successfully.</returns>
        private bool RemoveMessage(DbTransaction transaction, PageInfo page, int id, bool removeReplies)
        {
            string nspace, name;
            NameTools.ExpandFullName(page.FullName, out nspace, out name);
            if(nspace == null) nspace = "";

            Message[] messages = GetMessages(transaction, page);
            if(messages == null) return false;
            Message message = FindMessage(messages, id);
            if(message == null) return false;
            Message parent = FindAnchestor(messages, id);
            int parentId = parent != null ? parent.ID : -1;

            UnindexMessage(page, message.ID, message.Subject, message.DateTime, message.Body, transaction);

            if(removeReplies) {
                // Recursively remove all replies BEFORE removing parent (depth-first)
                foreach(Message reply in message.Replies) {
                    if(!RemoveMessage(transaction, page, reply.ID, true)) return false;
                }
            }

            // Remove this message
            ICommandBuilder builder = GetCommandBuilder();
            QueryBuilder queryBuilder = new QueryBuilder(builder);

            string query = queryBuilder.DeleteFrom("Message");
            query = queryBuilder.Where(query, "Page", WhereOperator.Equals, "Page");
            query = queryBuilder.AndWhere(query, "Namespace", WhereOperator.Equals, "Namespace");
            query = queryBuilder.AndWhere(query, "Id", WhereOperator.Equals, "Id");

            List<Parameter> parameters = new List<Parameter>(3);
            parameters.Add(new Parameter(ParameterType.String, "Page", name));
            parameters.Add(new Parameter(ParameterType.String, "Namespace", nspace));
            parameters.Add(new Parameter(ParameterType.Int16, "Id", (short)id));

            DbCommand command = builder.GetCommand(transaction, query, parameters);

            int rows = ExecuteNonQuery(command, false);

            if(!removeReplies && rows == 1) {
                // Update replies' parent id

                query = queryBuilder.Update("Message", new string[] { "Parent" }, new string[] { "NewParent" });
                query = queryBuilder.Where(query, "Page", WhereOperator.Equals, "Page");
                query = queryBuilder.AndWhere(query, "Namespace", WhereOperator.Equals, "Namespace");
                query = queryBuilder.AndWhere(query, "Parent", WhereOperator.Equals, "OldParent");

                parameters = new List<Parameter>(4);
                if(parentId != -1) parameters.Add(new Parameter(ParameterType.Int16, "NewParent", parentId));
                else parameters.Add(new Parameter(ParameterType.Int16, "NewParent", DBNull.Value));
                parameters.Add(new Parameter(ParameterType.String, "Page", name));
                parameters.Add(new Parameter(ParameterType.String, "Namespace", nspace));
                parameters.Add(new Parameter(ParameterType.Int16, "OldParent", (short)id));

                command = builder.GetCommand(transaction, query, parameters);

                rows = ExecuteNonQuery(command, false);
            }

            return rows > 0;
        }
        /// <summary>
        /// Sets the number of times a page attachment was retrieved.
        /// </summary>
        /// <param name="pageInfo">The page.</param>
        /// <param name="name">The name of the attachment.</param>
        /// <param name="count">The count to set.</param>
        /// <exception cref="ArgumentNullException">If <paramref name="pageInfo"/> or <paramref name="name"/> are <c>null</c>.</exception>
        /// <exception cref="ArgumentException">If <paramref name="name"/> is empty.</exception>
        /// <exception cref="ArgumentOutOfRangeException">If <paramref name="count"/> is less than zero.</exception>
        public void SetPageAttachmentRetrievalCount(PageInfo pageInfo, string name, int count)
        {
            if(pageInfo == null) throw new ArgumentNullException("pageInfo");
            if(name == null) throw new ArgumentNullException("name");
            if(name.Length == 0) throw new ArgumentException("Name cannot be empty");
            if(count < 0) throw new ArgumentOutOfRangeException("Count must be greater than or equal to zero", "count");

            ICommandBuilder builder = GetCommandBuilder();
            QueryBuilder queryBuilder = new QueryBuilder(builder);

            string query = queryBuilder.Update("Attachment", new string[] { "Downloads" }, new string[] { "Downloads" });
            query = queryBuilder.Where(query, "Name", WhereOperator.Equals, "Name");
            query = queryBuilder.AndWhere(query, "Page", WhereOperator.Equals, "Page");

            List<Parameter> parameters = new List<Parameter>(2);
            parameters.Add(new Parameter(ParameterType.String, "Name", name));
            parameters.Add(new Parameter(ParameterType.String, "Page", pageInfo.FullName));
            parameters.Add(new Parameter(ParameterType.Int32, "Downloads", count));

            DbCommand command = builder.GetCommand(connString, query, parameters);

            ExecuteNonQuery(command);
        }
        /// <summary>
        /// Modifies a user group.
        /// </summary>
        /// <param name="group">The group to modify.</param>
        /// <param name="description">The new description of the group.</param>
        /// <returns>The correct <see cref="T:UserGroup"/> object or <c>null</c>.</returns>
        /// <exception cref="ArgumentNullException">If <b>group</b> or <b>description</b> are <c>null</c>.</exception>
        public UserGroup ModifyUserGroup(UserGroup group, string description)
        {
            if(group == null) throw new ArgumentNullException("group");
            if(description == null) throw new ArgumentNullException("description");

            ICommandBuilder builder = GetCommandBuilder();
            DbConnection connection = builder.GetConnection(connString);
            DbTransaction transaction = BeginTransaction(connection);

            QueryBuilder queryBuilder = new QueryBuilder(builder);

            string query = queryBuilder.Update("UserGroup",
                new string[] { "Description" }, new string[] { "Description" });
            query = queryBuilder.Where(query, "Name", WhereOperator.Equals, "Name");

            List<Parameter> parameters = new List<Parameter>(2);
            parameters.Add(new Parameter(ParameterType.String, "Description", description));
            parameters.Add(new Parameter(ParameterType.String, "Name", group.Name));

            DbCommand command = builder.GetCommand(transaction, query, parameters);

            int rows = ExecuteNonQuery(command, false);

            if(rows == 1) {
                UserGroup result = new UserGroup(group.Name, description, this);
                result.Users = GetUserGroupUsers(transaction, group.Name);

                CommitTransaction(transaction);
                return result;
            }
            else {
                RollbackTransaction(transaction);
                return null;
            }
        }
        /// <summary>
        /// Renames a Category.
        /// </summary>
        /// <param name="category">The Category to rename.</param>
        /// <param name="newName">The new Name.</param>
        /// <returns>The correct CategoryInfo object.</returns>
        /// <exception cref="ArgumentNullException">If <paramref name="category"/> or <paramref name="newName"/> are <c>null</c>.</exception>
        /// <exception cref="ArgumentException">If <paramref name="newName"/> is empty.</exception>
        public CategoryInfo RenameCategory(CategoryInfo category, string newName)
        {
            if(category == null) throw new ArgumentNullException("category");
            if(newName == null) throw new ArgumentNullException("newName");
            if(newName.Length == 0) throw new ArgumentException("New Name cannot be empty", "newName");

            string nspace = null;
            string name = null;
            NameTools.ExpandFullName(category.FullName, out nspace, out name);
            if(nspace == null) nspace = "";

            ICommandBuilder builder = GetCommandBuilder();
            DbConnection connection = builder.GetConnection(connString);
            DbTransaction transaction = BeginTransaction(connection);

            QueryBuilder queryBuilder = new QueryBuilder(builder);

            string query = queryBuilder.Update("Category", new string[] { "Name" }, new string[] { "NewName" });
            query = queryBuilder.Where(query, "Name", WhereOperator.Equals, "OldName");
            query = queryBuilder.AndWhere(query, "Namespace", WhereOperator.Equals, "Namespace");

            List<Parameter> parameters = new List<Parameter>(3);
            parameters.Add(new Parameter(ParameterType.String, "NewName", newName));
            parameters.Add(new Parameter(ParameterType.String, "OldName", name));
            parameters.Add(new Parameter(ParameterType.String, "Namespace", nspace));

            DbCommand command = builder.GetCommand(transaction, query, parameters);

            int rows = ExecuteNonQuery(command, false);

            if(rows > 0) {
                CategoryInfo result = GetCategory(transaction, NameTools.GetFullName(nspace, newName));
                CommitTransaction(transaction);
                return result;
            }
            else {
                RollbackTransaction(transaction);
                return null;
            }
        }
        /// <summary>
        /// Renames a namespace.
        /// </summary>
        /// <param name="nspace">The namespace to rename.</param>
        /// <param name="newName">The new name of the namespace.</param>
        /// <returns>The correct <see cref="T:NamespaceInfo"/> object.</returns>
        /// <exception cref="ArgumentNullException">If <paramref name="nspace"/> or <paramref name="newName"/> are <c>null</c>.</exception>
        /// <exception cref="ArgumentException">If <paramref name="newName"/> is empty.</exception>
        public NamespaceInfo RenameNamespace(NamespaceInfo nspace, string newName)
        {
            if(nspace == null) throw new ArgumentNullException("nspace");
            if(newName == null) throw new ArgumentNullException("newName");
            if(newName.Length == 0) throw new ArgumentException("New Name cannot be empty", "newName");

            ICommandBuilder builder = GetCommandBuilder();
            DbConnection connection = builder.GetConnection(connString);
            DbTransaction transaction = BeginTransaction(connection);

            if(GetNamespace(transaction, nspace.Name) == null) {
                RollbackTransaction(transaction);
                return null;
            }

            foreach(PageInfo page in GetPages(transaction, nspace)) {
                PageContent content = GetContent(transaction, page, CurrentRevision);
                if(content != null) {
                    UnindexPage(content, transaction);
                }
                Message[] messages = GetMessages(transaction, page);
                if(messages != null) {
                    foreach(Message msg in messages) {
                        UnindexMessageTree(page, msg, transaction);
                    }
                }
            }

            QueryBuilder queryBuilder = new QueryBuilder(builder);

            string query = queryBuilder.Update("Namespace", new string[] { "Name" }, new string[] { "NewName" });
            query = queryBuilder.Where(query, "Name", WhereOperator.Equals, "OldName");

            List<Parameter> parameters = new List<Parameter>(2);
            parameters.Add(new Parameter(ParameterType.String, "NewName", newName));
            parameters.Add(new Parameter(ParameterType.String, "OldName", nspace.Name));

            DbCommand command = builder.GetCommand(transaction, query, parameters);

            int rows = ExecuteNonQuery(command, false);

            if(rows > 0) {
                NamespaceInfo result = GetNamespace(transaction, newName);

                foreach(PageInfo page in GetPages(transaction, result)) {
                    PageContent content = GetContent(transaction, page, CurrentRevision);
                    if(content != null) {
                        IndexPage(content, transaction);
                    }
                    Message[] messages = GetMessages(transaction, page);
                    if(messages != null) {
                        foreach(Message msg in messages) {
                            IndexMessageTree(page, msg, transaction);
                        }
                    }
                }

                CommitTransaction(transaction);

                return result;
            }
            else {
                RollbackTransaction(transaction);
                return null;
            }
        }
        /// <summary>
        /// Modifies a Message.
        /// </summary>
        /// <param name="page">The Page.</param>
        /// <param name="id">The ID of the Message to modify.</param>
        /// <param name="username">The Username.</param>
        /// <param name="subject">The Subject.</param>
        /// <param name="dateTime">The Date/Time.</param>
        /// <param name="body">The Body.</param>
        /// <returns>True if the Message is modified successfully.</returns>
        /// <exception cref="ArgumentNullException">If <paramref name="page"/>, <paramref name="username"/>, <paramref name="subject"/> or <paramref name="body"/> are <c>null</c>.</exception>
        /// <exception cref="ArgumentOutOfRangeException">If <paramref name="id"/> is less than zero.</exception>
        /// <exception cref="ArgumentException">If <paramref name="username"/> or <paramref name="subject"/> are empty.</exception>
        public bool ModifyMessage(PageInfo page, int id, string username, string subject, DateTime dateTime, string body)
        {
            if(page == null) throw new ArgumentNullException("page");
            if(id < 0) throw new ArgumentOutOfRangeException("id", "Invalid Message ID");
            if(username == null) throw new ArgumentNullException("username");
            if(username.Length == 0) throw new ArgumentException("Username cannot be empty", "username");
            if(subject == null) throw new ArgumentNullException("subject");
            if(subject.Length == 0) throw new ArgumentException("Subject cannot be empty", "subject");
            if(body == null) throw new ArgumentNullException("body"); // body can be empty

            string nspace, name;
            NameTools.ExpandFullName(page.FullName, out nspace, out name);
            if(nspace == null) nspace = "";

            ICommandBuilder builder = GetCommandBuilder();
            DbConnection connection = builder.GetConnection(connString);
            DbTransaction transaction = BeginTransaction(connection);

            Message[] messages = GetMessages(transaction, page);
            if(messages == null) {
                RollbackTransaction(transaction);
                return false;
            }
            Message oldMessage = FindMessage(messages, id);

            if(oldMessage == null) {
                RollbackTransaction(transaction);
                return false;
            }

            UnindexMessage(page, oldMessage.ID, oldMessage.Subject, oldMessage.DateTime, oldMessage.Body, transaction);

            QueryBuilder queryBuilder = new QueryBuilder(builder);

            string query = queryBuilder.Update("Message", new string[] { "Username", "Subject", "DateTime", "Body" }, new string[] { "Username", "Subject", "DateTime", "Body" });
            query = queryBuilder.Where(query, "Page", WhereOperator.Equals, "Page");
            query = queryBuilder.AndWhere(query, "Namespace", WhereOperator.Equals, "Namespace");
            query = queryBuilder.AndWhere(query, "Id", WhereOperator.Equals, "Id");

            List<Parameter> parameters = new List<Parameter>(7);
            parameters.Add(new Parameter(ParameterType.String, "Username", username));
            parameters.Add(new Parameter(ParameterType.String, "Subject", subject));
            parameters.Add(new Parameter(ParameterType.DateTime, "DateTime", dateTime));
            parameters.Add(new Parameter(ParameterType.String, "Body", body));
            parameters.Add(new Parameter(ParameterType.String, "Page", name));
            parameters.Add(new Parameter(ParameterType.String, "Namespace", nspace));
            parameters.Add(new Parameter(ParameterType.Int16, "Id", id));

            DbCommand command = builder.GetCommand(transaction, query, parameters);

            int rows = ExecuteNonQuery(command, false);

            if(rows == 1) {
                IndexMessage(page, id, subject, dateTime, body, transaction);
                CommitTransaction(transaction);
                return true;
            }
            else {
                RollbackTransaction(transaction);
                return false;
            }
        }
        /// <summary>
        /// Moves a page from its namespace into another.
        /// </summary>
        /// <param name="page">The page to move.</param>
        /// <param name="destination">The destination namespace (<c>null</c> for the root).</param>
        /// <param name="copyCategories">A value indicating whether to copy the page categories in the destination
        /// namespace, if not already available.</param>
        /// <returns>The correct instance of <see cref="T:PageInfo"/>.</returns>
        /// <exception cref="ArgumentNullException">If <paramref name="page"/> is <c>null</c>.</exception>
        public PageInfo MovePage(PageInfo page, NamespaceInfo destination, bool copyCategories)
        {
            if(page == null) throw new ArgumentNullException("page");

            // Check:
            // 1. Same namespace - ROOT, SUB (explicit check)
            // 2. Destination existence (update query affects 0 rows because it would break a FK)
            // 3. Page existence in target (update query affects 0 rows because it would break a FK)
            // 4. Page is default page of its namespace (explicit check)

            string destinationName = destination != null ? destination.Name : "";
            string sourceName = null;
            string pageName = null;
            NameTools.ExpandFullName(page.FullName, out sourceName, out pageName);
            if(sourceName == null) sourceName = "";

            ICommandBuilder builder = GetCommandBuilder();
            DbConnection connection = builder.GetConnection(connString);
            DbTransaction transaction = BeginTransaction(connection);

            if(destinationName.ToLowerInvariant() == sourceName.ToLowerInvariant()) return null;
            if(IsDefaultPage(transaction, page)) {
                RollbackTransaction(transaction);
                return null;
            }

            PageContent currentContent = GetContent(transaction, page, CurrentRevision);
            if(currentContent != null) {
                UnindexPage(currentContent, transaction);
                foreach(Message msg in GetMessages(transaction, page)) {
                    UnindexMessageTree(page, msg, transaction);
                }
            }

            CategoryInfo[] currCategories = GetCategories(transaction, sourceName == "" ? null : GetNamespace(transaction, sourceName));

            // Remove bindings
            RebindPage(transaction, page, new string[0]);

            string[] newCategories = new string[0];

            if(copyCategories) {
                // Retrieve categories for page
                // Copy missing ones in destination

                string lowerPageName = page.FullName.ToLowerInvariant();

                List<string> pageCategories = new List<string>(10);
                foreach(CategoryInfo cat in currCategories) {
                    if(Array.Find(cat.Pages, (s) => { return s.ToLowerInvariant() == lowerPageName; }) != null) {
                        pageCategories.Add(NameTools.GetLocalName(cat.FullName));
                    }
                }

                // Create categories into destination without checking existence (AddCategory will return null)
                string tempName = destinationName == "" ? null : destinationName;
                newCategories = new string[pageCategories.Count];

                for(int i = 0; i < pageCategories.Count; i++) {
                    string catName = NameTools.GetFullName(tempName, pageCategories[i]);
                    if(GetCategory(transaction, catName) == null) {
                        CategoryInfo added = AddCategory(tempName, pageCategories[i]);
                    }
                    newCategories[i] = catName;
                }
            }

            QueryBuilder queryBuilder = new QueryBuilder(builder);

            string query = queryBuilder.Update("Page", new string[] { "Namespace" }, new string[] { "Destination" });
            query = queryBuilder.Where(query, "Name", WhereOperator.Equals, "Name");
            query = queryBuilder.AndWhere(query, "Namespace", WhereOperator.Equals, "Source");

            List<Parameter> parameters = new List<Parameter>(3);
            parameters.Add(new Parameter(ParameterType.String, "Destination", destinationName));
            parameters.Add(new Parameter(ParameterType.String, "Name", pageName));
            parameters.Add(new Parameter(ParameterType.String, "Source", sourceName));

            DbCommand command = builder.GetCommand(transaction, query, parameters);

            int rows = ExecuteNonQuery(command, false);

            if(rows > 0) {
                PageInfo result = new PageInfo(NameTools.GetFullName(destinationName, pageName), this, page.CreationDateTime);

                // Re-bind categories
                if(copyCategories) {
                    bool rebound = RebindPage(transaction, result, newCategories);
                    if(!rebound) {
                        RollbackTransaction(transaction);
                        return null;
                    }
                }

                PageContent newContent = GetContent(transaction, result, CurrentRevision);
                IndexPage(newContent, transaction);
                foreach(Message msg in GetMessages(transaction, result)) {
                    IndexMessageTree(result, msg, transaction);
                }

                CommitTransaction(transaction);

                return result;
            }
            else {
                RollbackTransaction(transaction);
                return null;
            }
        }
        /// <summary>
        /// Updates all outgoing links data for a page rename.
        /// </summary>
        /// <param name="oldName">The old page name.</param>
        /// <param name="newName">The new page name.</param>
        /// <returns><c>true</c> if the data is updated, <c>false</c> otherwise.</returns>
        /// <exception cref="ArgumentNullException">If <b>oldName</b> or <b>newName</b> are <c>null</c>.</exception>
        /// <exception cref="ArgumentException">If <b>oldName</b> or <b>newName</b> are empty.</exception>
        public bool UpdateOutgoingLinksForRename(string oldName, string newName)
        {
            if(oldName == null) throw new ArgumentNullException("oldName");
            if(oldName.Length == 0) throw new ArgumentException("Old Name cannot be empty", "oldName");
            if(newName == null) throw new ArgumentNullException("newName");
            if(newName.Length == 0) throw new ArgumentException("New Name cannot be empty", "newName");

            // 1. Rename sources
            // 2. Rename destinations

            ICommandBuilder builder = GetCommandBuilder();
            DbConnection connection = builder.GetConnection(connString);
            DbTransaction transaction = BeginTransaction(connection);

            QueryBuilder queryBuilder = new QueryBuilder(builder);

            string query = queryBuilder.Update("OutgoingLink", new string[] { "Source" }, new string[] { "NewSource" });
            query = queryBuilder.Where(query, "Source", WhereOperator.Equals, "OldSource");

            List<Parameter> parameters = new List<Parameter>(2);
            parameters.Add(new Parameter(ParameterType.String, "NewSource", newName));
            parameters.Add(new Parameter(ParameterType.String, "OldSource", oldName));

            DbCommand command = builder.GetCommand(transaction, query, parameters);

            int rows = ExecuteNonQuery(command, false);

            if(rows == -1) {
                RollbackTransaction(transaction);
                return false;
            }

            bool somethingUpdated = rows > 0;

            query = queryBuilder.Update("OutgoingLink", new string[] { "Destination" }, new string[] { "NewDestination" });
            query = queryBuilder.Where(query, "Destination", WhereOperator.Equals, "OldDestination");

            parameters = new List<Parameter>(2);
            parameters.Add(new Parameter(ParameterType.String, "NewDestination", newName));
            parameters.Add(new Parameter(ParameterType.String, "OldDestination", oldName));

            command = builder.GetCommand(transaction, query, parameters);

            rows = ExecuteNonQuery(command, false);

            if(rows >= 0) CommitTransaction(transaction);
            else RollbackTransaction(transaction);

            return somethingUpdated || rows > 0;
        }
        /// <summary>
        /// Sets the status of a plugin.
        /// </summary>
        /// <param name="typeName">The Type name of the plugin.</param>
        /// <param name="enabled">The plugin status.</param>
        /// <returns><c>true</c> if the status is stored, <c>false</c> otherwise.</returns>
        /// <exception cref="ArgumentNullException">If <b>typeName</b> is <c>null</c>.</exception>
        /// <exception cref="ArgumentException">If <b>typeName</b> is empty.</exception>
        public bool SetPluginStatus(string typeName, bool enabled)
        {
            if(typeName == null) throw new ArgumentNullException("typeName");
            if(typeName.Length == 0) throw new ArgumentException("Type Name cannot be empty", "typeName");

            ICommandBuilder builder = GetCommandBuilder();
            DbConnection connection = builder.GetConnection(connString);
            DbTransaction transaction = BeginTransaction(connection);

            PreparePluginStatusRow(transaction, typeName);

            QueryBuilder queryBuilder = new QueryBuilder(builder);

            string query = queryBuilder.Update("PluginStatus", new string[] { "Enabled" }, new string[] { "Enabled" });
            query = queryBuilder.Where(query, "Name", WhereOperator.Equals, "Name");

            List<Parameter> parameters = new List<Parameter>(2);
            parameters.Add(new Parameter(ParameterType.Boolean, "Enabled", enabled));
            parameters.Add(new Parameter(ParameterType.String, "Name", typeName));

            DbCommand command = builder.GetCommand(transaction, query, parameters);

            int rows = ExecuteNonQuery(command, false);

            if(rows == 1) CommitTransaction(transaction);
            else RollbackTransaction(transaction);

            return rows == 1;
        }
        /// <summary>
        /// Renames a ACL resource.
        /// </summary>
        /// <param name="resource">The resource to rename.</param>
        /// <param name="newName">The new name of the resource.</param>
        /// <returns><c>true</c> if one or more entries weere updated, <c>false</c> otherwise.</returns>
        private bool RenameAclResource(string resource, string newName)
        {
            ICommandBuilder builder = GetCommandBuilder();
            DbConnection connection = builder.GetConnection(connString);
            DbTransaction transaction = BeginTransaction(connection);

            QueryBuilder queryBuilder = new QueryBuilder(builder);

            string query = queryBuilder.Update("AclEntry", new[] { "Resource" }, new[] { "ResourceNew" });
            query = queryBuilder.Where(query, "Resource", WhereOperator.Equals, "ResourceOld");

            List<Parameter> parameters = new List<Parameter>(2);
            parameters.Add(new Parameter(ParameterType.String, "ResourceNew", newName));
            parameters.Add(new Parameter(ParameterType.String, "ResourceOld", resource));

            DbCommand command = builder.GetCommand(transaction, query, parameters);

            if(ExecuteNonQuery(command, false) <= 0) {
                RollbackTransaction(transaction);
                return false;
            }

            CommitTransaction(transaction);

            return true;
        }
        /// <summary>
        /// Renames a Page Attachment.
        /// </summary>
        /// <param name="pageInfo">The Page Info that owns the Attachment.</param>
        /// <param name="oldName">The old name of the Attachment.</param>
        /// <param name="newName">The new name of the Attachment.</param>
        /// <returns><c>true</c> if the Attachment is renamed, false otherwise.</returns>
        /// <exception cref="ArgumentNullException">If <paramref name="pageInfo"/>, <paramref name="oldName"/> or <paramref name="newName"/> are <c>null</c>.</exception>
        /// <exception cref="ArgumentException">If <paramref name="pageInfo"/>, <paramref name="oldName"/> or <paramref name="newName"/> are empty,
        /// or if the page or old attachment do not exist, or the new attachment name already exists.</exception>
        public bool RenamePageAttachment(PageInfo pageInfo, string oldName, string newName)
        {
            if(pageInfo == null) throw new ArgumentNullException("pageInfo");
            if(oldName == null) throw new ArgumentNullException("oldName");
            if(oldName.Length == 0) throw new ArgumentException("Old Name cannot be empty", "oldName");
            if(newName == null) throw new ArgumentNullException("newName");
            if(newName.Length == 0) throw new ArgumentException("New Name cannot be empty", "newName");

            ICommandBuilder builder = GetCommandBuilder();
            DbConnection connection = builder.GetConnection(connString);
            DbTransaction transaction = BeginTransaction(connection);

            if(!AttachmentExists(transaction, pageInfo, oldName)) {
                RollbackTransaction(transaction);
                throw new ArgumentException("Attachment does not exist", "name");
            }
            if(AttachmentExists(transaction, pageInfo, newName)) {
                RollbackTransaction(transaction);
                throw new ArgumentException("Attachment already exists", "name");
            }

            QueryBuilder queryBuilder = new QueryBuilder(builder);

            string query = queryBuilder.Update("Attachment", new string[] { "Name" }, new string[] { "NewName" });
            query = queryBuilder.Where(query, "Name", WhereOperator.Equals, "OldName");
            query = queryBuilder.AndWhere(query, "Page", WhereOperator.Equals, "Page");

            List<Parameter> parameters = new List<Parameter>(3);
            parameters.Add(new Parameter(ParameterType.String, "NewName", newName));
            parameters.Add(new Parameter(ParameterType.String, "OldName", oldName));
            parameters.Add(new Parameter(ParameterType.String, "Page", pageInfo.FullName));

            DbCommand command = builder.GetCommand(transaction, query, parameters);

            int rows = ExecuteNonQuery(command, false);
            if(rows == 1) CommitTransaction(transaction);
            else RollbackTransaction(transaction);

            return rows == 1;
        }
        /// <summary>
        /// Renames a Page.
        /// </summary>
        /// <param name="page">The Page to rename.</param>
        /// <param name="newName">The new Name.</param>
        /// <returns>The correct <see cref="T:PageInfo"/> object.</returns>
        /// <exception cref="ArgumentNullException">If <paramref name="page"/> or <paramref name="newName"/> are <c>null</c>.</exception>
        /// <exception cref="ArgumentException">If <paramref name="newName"/> is empty.</exception>
        public PageInfo RenamePage(PageInfo page, string newName)
        {
            if(page == null) throw new ArgumentNullException("page");
            if(newName == null) throw new ArgumentNullException("newName");
            if(newName.Length == 0) throw new ArgumentException("New Name cannot be empty", "newName");

            // Check
            // 1. Page is default page of its namespace
            // 2. New name already exists

            ICommandBuilder builder = GetCommandBuilder();
            DbConnection connection = builder.GetConnection(connString);
            DbTransaction transaction = BeginTransaction(connection);

            if(GetPage(transaction, page.FullName) == null) {
                RollbackTransaction(transaction);
                return null;
            }
            if(IsDefaultPage(transaction, page)) {
                RollbackTransaction(transaction);
                return null;
            }
            if(GetPage(transaction, NameTools.GetFullName(NameTools.GetNamespace(page.FullName), NameTools.GetLocalName(newName))) != null) {
                RollbackTransaction(transaction);
                return null;
            }

            PageContent currentContent = GetContent(transaction, page, CurrentRevision);
            UnindexPage(currentContent, transaction);
            foreach(Message msg in GetMessages(transaction, page)) {
                UnindexMessageTree(page, msg, transaction);
            }

            string nspace, name;
            NameTools.ExpandFullName(page.FullName, out nspace, out name);
            if(nspace == null) nspace = "";

            CategoryInfo[] currCategories = GetCategories(transaction, nspace == "" ? null : GetNamespace(transaction, nspace));
            string lowerPageName = page.FullName.ToLowerInvariant();
            List<string> pageCategories = new List<string>(10);
            foreach(CategoryInfo cat in currCategories) {
                if(Array.Find(cat.Pages, (s) => { return s.ToLowerInvariant() == lowerPageName; }) != null) {
                    pageCategories.Add(NameTools.GetLocalName(cat.FullName));
                }
            }

            RebindPage(transaction, page, new string[0]);

            QueryBuilder queryBuilder = new QueryBuilder(builder);

            string query = queryBuilder.Update("Page", new string[] { "Name" }, new string[] { "NewName" });
            query = queryBuilder.Where(query, "Name", WhereOperator.Equals, "OldName");
            query = queryBuilder.AndWhere(query, "Namespace", WhereOperator.Equals, "Namespace");

            List<Parameter> parameters = new List<Parameter>(3);
            parameters.Add(new Parameter(ParameterType.String, "NewName", newName));
            parameters.Add(new Parameter(ParameterType.String, "OldName", name));
            parameters.Add(new Parameter(ParameterType.String, "Namespace", nspace));

            DbCommand command = builder.GetCommand(transaction, query, parameters);

            int rows = ExecuteNonQuery(command, false);

            if(rows > 0) {
                PageInfo result = new PageInfo(NameTools.GetFullName(nspace, newName), this, page.CreationDateTime);

                RebindPage(transaction, result, pageCategories.ToArray());

                PageContent newContent = GetContent(transaction, result, CurrentRevision);

                IndexPage(newContent, transaction);
                foreach(Message msg in GetMessages(transaction, result)) {
                    IndexMessageTree(result, msg, transaction);
                }

                CommitTransaction(transaction);

                return result;
            }
            else {
                RollbackTransaction(transaction);
                return null;
            }
        }
        /// <summary>
        /// Sets the number of times a file was retrieved.
        /// </summary>
        /// <param name="fullName">The full name of the file.</param>
        /// <param name="count">The count to set.</param>
        /// <exception cref="ArgumentNullException">If <paramref name="fullName"/> is <c>null</c>.</exception>
        /// <exception cref="ArgumentException">If <paramref name="fullName"/> is empty.</exception>
        /// <exception cref="ArgumentOutOfRangeException">If <paramref name="count"/> is less than zero.</exception>
        public void SetFileRetrievalCount(string fullName, int count)
        {
            if(fullName == null) throw new ArgumentNullException("fullName");
            if(fullName.Length == 0) throw new ArgumentException("Full Name cannot be empty", "fullName");
            if(count < 0) throw new ArgumentOutOfRangeException("count", "Count must be greater than or equal to zero");

            ICommandBuilder builder = GetCommandBuilder();
            QueryBuilder queryBuilder = new QueryBuilder(builder);

            string directory, filename;
            SplitFileFullName(fullName, out directory, out filename);

            string query = queryBuilder.Update("File", new string[] { "Downloads" }, new string[] { "Downloads" });
            query = queryBuilder.Where(query, "Name", WhereOperator.Equals, "Name");
            query = queryBuilder.AndWhere(query, "Directory", WhereOperator.Equals, "Directory");

            List<Parameter> parameters = new List<Parameter>(2);
            parameters.Add(new Parameter(ParameterType.String, "Name", filename));
            parameters.Add(new Parameter(ParameterType.String, "Directory", directory));
            parameters.Add(new Parameter(ParameterType.Int32, "Downloads", count));

            DbCommand command = builder.GetCommand(connString, query, parameters);

            ExecuteNonQuery(command);
        }
        /// <summary>
        /// Sets the default page of a namespace.
        /// </summary>
        /// <param name="nspace">The namespace of which to set the default page.</param>
        /// <param name="page">The page to use as default page, or <c>null</c>.</param>
        /// <returns>The correct <see cref="T:NamespaceInfo"/> object.</returns>
        /// <exception cref="ArgumentNullException">If <paramref name="nspace"/> is <c>null</c>.</exception>
        public NamespaceInfo SetNamespaceDefaultPage(NamespaceInfo nspace, PageInfo page)
        {
            if(nspace == null) throw new ArgumentNullException("nspace");

            // Namespace existence is verified by the affected rows (should be 1)

            ICommandBuilder builder = GetCommandBuilder();
            DbConnection connection = builder.GetConnection(connString);
            DbTransaction transaction = BeginTransaction(connection);

            if(page != null && GetPage(transaction, page.FullName) == null) {
                RollbackTransaction(transaction);
                return null;
            }

            QueryBuilder queryBuilder = new QueryBuilder(builder);

            string query = queryBuilder.Update("Namespace", new string[] { "DefaultPage" }, new string[] { "DefaultPage" });
            query = queryBuilder.Where(query, "Name", WhereOperator.Equals, "Name");

            List<Parameter> parameters = new List<Parameter>(2);
            if(page == null) parameters.Add(new Parameter(ParameterType.String, "DefaultPage", DBNull.Value));
            else parameters.Add(new Parameter(ParameterType.String, "DefaultPage", NameTools.GetLocalName(page.FullName)));
            parameters.Add(new Parameter(ParameterType.String, "Name", nspace.Name));

            DbCommand command = builder.GetCommand(transaction, query, parameters);

            int rows = ExecuteNonQuery(command, false);

            if(rows == 1) {
                CommitTransaction(transaction);
                return new NamespaceInfo(nspace.Name, this, page);
            }
            else {
                RollbackTransaction(transaction);
                return null;
            }
        }
        /// <summary>
        /// Stores a Page Attachment.
        /// </summary>
        /// <param name="pageInfo">The Page Info that owns the Attachment.</param>
        /// <param name="name">The name of the Attachment, for example "myfile.jpg".</param>
        /// <param name="sourceStream">A Stream object used as <b>source</b> of a byte stream,
        /// i.e. the method reads from the Stream and stores the content properly.</param>
        /// <param name="overwrite"><c>true</c> to overwrite an existing Attachment.</param>
        /// <returns><c>true</c> if the Attachment is stored, <c>false</c> otherwise.</returns>
        /// <remarks>If <b>overwrite</b> is <c>false</c> and Attachment already exists, the method returns <c>false</c>.</remarks>
        /// <exception cref="ArgumentNullException">If <paramref name="pageInfo"/>, <paramref name="name"/> or <paramref name="sourceStream"/> are <c>null</c>.</exception>
        /// <exception cref="ArgumentException">If <paramref name="name"/> is empty or if <paramref name="sourceStream"/> does not support reading.</exception>
        public bool StorePageAttachment(PageInfo pageInfo, string name, System.IO.Stream sourceStream, bool overwrite)
        {
            if(pageInfo == null) throw new ArgumentNullException("pageInfo");
            if(name == null) throw new ArgumentNullException("name");
            if(name.Length == 0) throw new ArgumentException("Name cannot be empty", "name");
            if(sourceStream == null) throw new ArgumentNullException("sourceStream");
            if(!sourceStream.CanRead) throw new ArgumentException("Cannot read from Source Stream", "sourceStream");

            ICommandBuilder builder = GetCommandBuilder();
            DbConnection connection = builder.GetConnection(connString);
            DbTransaction transaction = BeginTransaction(connection);

            bool attachmentExists = AttachmentExists(transaction, pageInfo, name);

            if(attachmentExists && !overwrite) {
                RollbackTransaction(transaction);
                return false;
            }

            // To achieve decent performance, an UPDATE query is issued if the attachment exists,
            // otherwise an INSERT query is issued

            QueryBuilder queryBuilder = new QueryBuilder(builder);

            string query;
            List<Parameter> parameters;

            byte[] attachmentData = null;
            int size = Tools.ReadStream(sourceStream, ref attachmentData, MaxFileSize);
            if(size < 0) {
                RollbackTransaction(transaction);
                throw new ArgumentException("Source Stream contains too much data", "sourceStream");
            }

            if(attachmentExists) {
                query = queryBuilder.Update("Attachment", new string[] { "Size", "LastModified", "Data" }, new string[] { "Size", "LastModified", "Data" });
                query = queryBuilder.Where(query, "Name", WhereOperator.Equals, "Name");
                query = queryBuilder.AndWhere(query, "Page", WhereOperator.Equals, "Page");

                parameters = new List<Parameter>(5);
                parameters.Add(new Parameter(ParameterType.Int64, "Size", (long)size));
                parameters.Add(new Parameter(ParameterType.DateTime, "LastModified", DateTime.Now));
                parameters.Add(new Parameter(ParameterType.ByteArray, "Data", attachmentData));
                parameters.Add(new Parameter(ParameterType.String, "Name", name));
                parameters.Add(new Parameter(ParameterType.String, "Page", pageInfo.FullName));
            }
            else {
                query = queryBuilder.InsertInto("Attachment", new string[] { "Name", "Page", "Size", "Downloads", "LastModified", "Data" },
                    new string[] { "Name", "Page", "Size", "Downloads", "LastModified", "Data" });

                parameters = new List<Parameter>(6);
                parameters.Add(new Parameter(ParameterType.String, "Name", name));
                parameters.Add(new Parameter(ParameterType.String, "Page", pageInfo.FullName));
                parameters.Add(new Parameter(ParameterType.Int64, "Size", (long)size));
                parameters.Add(new Parameter(ParameterType.Int32, "Downloads", 0));
                parameters.Add(new Parameter(ParameterType.DateTime, "LastModified", DateTime.Now));
                parameters.Add(new Parameter(ParameterType.ByteArray, "Data", attachmentData));
            }

            DbCommand command = builder.GetCommand(transaction, query, parameters);

            int rows = ExecuteNonQuery(command, false);
            if(rows == 1) CommitTransaction(transaction);
            else RollbackTransaction(transaction);

            return rows == 1;
        }
        /// <summary>
        /// Modifies a User.
        /// </summary>
        /// <param name="user">The Username of the user to modify.</param>
        /// <param name="newDisplayName">The new display name (can be <c>null</c>).</param>
        /// <param name="newPassword">The new Password (<c>null</c> or blank to keep the current password).</param>
        /// <param name="newEmail">The new Email address.</param>
        /// <param name="newActive">A value indicating whether the account is active.</param>
        /// <returns>The correct <see cref="T:UserInfo"/> object or <c>null</c>.</returns>
        /// <exception cref="ArgumentNullException">If <b>user</b> or <b>newEmail</b> are <c>null</c>.</exception>
        /// <exception cref="ArgumentException">If <b>newEmail</b> is empty.</exception>
        public UserInfo ModifyUser(UserInfo user, string newDisplayName, string newPassword, string newEmail, bool newActive)
        {
            if(user == null) throw new ArgumentNullException("user");
            if(newEmail == null) throw new ArgumentNullException("newEmail");
            if(newEmail.Length == 0) throw new ArgumentException("New Email cannot be empty", "newEmail");

            ICommandBuilder builder = GetCommandBuilder();
            DbConnection connection = builder.GetConnection(connString);
            DbTransaction transaction = BeginTransaction(connection);

            QueryBuilder queryBuilder = new QueryBuilder(builder);

            string query = "";
            if(string.IsNullOrEmpty(newPassword)) {
                query = queryBuilder.Update("User",
                    new string[] { "DisplayName", "Email", "Active", },
                    new string[] { "DisplayName", "Email", "Active", });
            }
            else {
                query = queryBuilder.Update("User",
                    new string[] { "PasswordHash", "DisplayName", "Email", "Active", },
                    new string[] { "PasswordHash", "DisplayName", "Email", "Active", });
            }
            query = queryBuilder.Where(query, "Username", WhereOperator.Equals, "Username");

            List<Parameter> parameters = new List<Parameter>(5);
            if(!string.IsNullOrEmpty(newPassword)) {
                parameters.Add(new Parameter(ParameterType.String, "PasswordHash", Hash.Compute(newPassword)));
            }
            if(string.IsNullOrEmpty(newDisplayName)) parameters.Add(new Parameter(ParameterType.String, "DisplayName", DBNull.Value));
            else parameters.Add(new Parameter(ParameterType.String, "DisplayName", newDisplayName));
            parameters.Add(new Parameter(ParameterType.String, "Email", newEmail));
            parameters.Add(new Parameter(ParameterType.Boolean, "Active", newActive));
            parameters.Add(new Parameter(ParameterType.String, "Username", user.Username));

            DbCommand command = builder.GetCommand(transaction, query, parameters);

            int rows = ExecuteNonQuery(command, false);

            if(rows == 1) {
                UserInfo result = new UserInfo(user.Username, newDisplayName, newEmail, newActive, user.DateTime, this);
                result.Groups = GetUserGroups(transaction, user.Username);

                CommitTransaction(transaction);
                return result;
            }
            else {
                RollbackTransaction(transaction);
                return null;
            }
        }