Database Management System - Coursework Example

Software Development Question A) Before Database Crash Set online database redo log Most databases has an online redo long. The background activites of the database uses the online redo log so that it can recover all record changed when a failure happen through the associated instance. Every record will contain both the the old and the new data. Every redo record will contain all values both new and the old values to the rollback block. 2. set the archived redo log Usually, you can configure a database to archive files of the online redo log by the time they fill. This online redo log file will uniquely be identified in their log sequence number hence this will make up the archived redo log. When archiving online redo log files previous redo log information is also preserved for tasks such as media recovery. You can set the pre-allocated online redo log file continue to be in use for storage of the resent database changes. 3. Set the redo log and rolling forward This is a set of the operating system files which keep record of all changes made in any database buffer, these changes include data, rollback segments and index, these a\changes are recorded whether they are committed or not committed. Every redo entry is a combination of vector like structure illustrating atomic change to the database. Always the redo secures changes made to database buffer in the memory which has not been written to a data file. After database crash 1. Identify the corrupted database After the crash identify the corrupted or crashed database. Once you identify the corrupted database investigate the possible cause of the failure. 2. Use database recovery software Once you have established the cause of the crash use database recovery software to recover the crashed database from the crashed database. In the process of database recovery make sure you restore it to the point where the database was that is ensuring you have the latest database data that was recorded before it had crashed. Question 1(B) Updating data Since changing of database information before doing anything on the problem at hand I will back up the database so that I may avoid future problems which may arise due to change of database records. After the database backup now I will interrogate the user on what kind of data was entered wrongly. Depending on the nature of the information I may take another action by involving the relevant authorities before I make any changes. After getting the green light on what to do I will now make correction by updating the information so that the system can give the right information. Question 2(A) Importance of data ware housing in organization management decision support. Business progress evaluation Data warehousing help in having the current and the previous data on the organization performance. Customer retention To evaluate the retention of customers is by queering the data ware house to determine whether the older customers still make transactions if not the organization should make follow up in order to bring them back on board. Management decision support The presence of information will have a great impact on the decision made by the top management of an organization. Question 2(B) I. Parallel server technology Parallel server technology coordinator looks individual operation in a SQL statement’s execution plan and then determines way in which each row operated on in the operation should be divided or shared among the parallel execution servers. The absence of parallel query features, the functionality of the SQL commands will always be carried out by single server process. III. Star queries The star query separates business operations data facts, of which has measurable quantitative information about the business, also the dimensions which are descriptive attributes related to the fact information. IV. Bitmapped indexes Bitmap indexes are most helpful in a data warehouse environment because they are generally great when you are only selecting data.. Question 3(A) Authentication The basic security requirement is identifying the user, the system user must be well known. They should be identified before their privileges can be determined and can be given access rights, so that user action can be audited. Authorization Authorization is the ability of a database to give permission of a user to have access of a database information after authentication has been done. Audit Auditing is the monitoring and recording of selected user database actions. Question 3 (B) SQL injection is a code injection technique, used to attack data-driven applications, in which malicious SQL statements are inserted into an entry field for execution. Example txtUserpassword = getRequestString("UserPassword"); txtSQL = "SELECT * FROM UserTable WHERE Userpassword = @0"; db.Execute(txtSQL,txtUserpassword); (II). Detecting SQL injection 1. Presence of Addition of a UNION clause 2. Presence of Addition of a foreign or strange subquery 3. Presence of Additional dummy conditions in the WHERE clause such as a=a or 1=1 4. Presence of SQL where supplied packages are called in inappropriate places 5. Presence of Access being made to system tables and/or application user and authentication tables 6. Presence of SQL in which the WHERE clause has been truncated with a comment. 7. Presence of Multiple errors indicating that select clauses have the wrong number of items or wrong data types 1. Indicates someone trying to create an extra select using a UNION 8. Presence of SQL accessing a honey pot row Preventing SQL injection Use BIND variables For one to prevent SQL injection should use bind variables all the time Create white lists Construct SQL from a list, not from user input Check for the use of || / " Check for high frequency of errors Question 3(C) To avoid the data manipulation by intruders To ensure data integrity Question 3(D) Enhance system security Promote data integrity Scalability: Determine the predictability of your data growth. Key management needs: From a security best practices perspective, management should be an independent entity from backup. Operational integration and management: All encryption options have some operational impact, but the specifics vary.  Question (4) 9. Roles in database management They ensure data integrity by ensuring there is limits of access among different system users at different levels of the organization. Information security some people may not have access to other information in the database since they do not have the rights of access. Question 4(II) a. Amy can update employees this is because the users in role 1 have the rights to update the content of the data base b. delete records since role to is granted to role one it mean that amy can delete records from the database. c. Explain why two different error messages are given in these circumstances. In the first one user has no privileges for changing any information. In error two the user privileges are also limited d. The view can be used to implement security at this level by ensuring all data in both row and column is consistent with the required data. e. In the columns for the view, the permissions for a column name apply across a CREATE VIEW or ALTER VIEW statement, regardless of the source of the underlying data. Read More