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| Pregunta | Respuesta |
| What is a database? | An organised, structured, collection of related data. designed to allow access by a number of different applications. It holds information about entities in a series of related tables. |
| What is a Primary Key | Uniquely identifies a record in a table. |
| What is a Composite Key? | It consists of two or more key fields. Each of which is a primary key in another table. |
| What is a Foreign Key? | A key field which is not a primary key in the table but which is a primary key in another table. Used to link tables together. |
| Data Consistency | A particular attribute has only one value throughout the database. A change to a data value is implemented throughout the database because it is held in only one table. |
| Data Integrity | Refers to the accuracy of data. Can be affected by input errors and processing errors. Minimised by data validation. |
| Data Redundancy | The same data is stored more than once causing the database to use up more storage space than required. This can lead to data inconsistency. |
| Data Independence | Data is kept separate from the programmes/software which processes it. |
| First Normal Form | A table is said to be in 1NF if it contains no repeating groups. |
| Second Normal Form | A table is in 2NF if it is in 1NF and every non-key attribute is functionally dependent on all parts of the primary key. |
| Third Normal Form | A table is in 3NF if it is in 2NF and if no functional dependencies exist between non key attributes. |
| Purpose of Data Normalisation | To help ensure that a database is structured in the best possible way for processing. To reduce data redundancy. To maximise data consistency. |
| Explain how data normalisation is carried out. | Any repeating group of attributes are removed to ensure the data is in 1NF. Attributes dependent on a partial key are removed to ensure the data is in 2NF. All non-key dependencies are removed to ensure data is in 3NF. |
| Describe the main components of a Database Management System (DBMS) | Three major components of a relational DBMS: Data definition language Data manipulation language Data dictionary. |
| Data Definition Language | The formal language used by programmes to specify the content and structure of the database. DDL is used to outline the entities requires for the application, and the relationships that may exist between them. |
| Data manipulation language (DML) | A specialised language used in conjunction with other generation programming languages to manipulate the data within the database. Contains commands that allow system users and programmers to extract data from the database in order to carry out user requests and enable applications development. |
| Data Dictionary | Automated or manual file that stores definitions of data elements and characteristics such as usage, ownership, authorisation and security. They are passive - they simply report. A change in the dictionary is automatically used by any related programs. |
| What is a DBMS? | An application program that provides an interface between the operating system and the user to make access to the data as simple as possible. |
| 1/5 functions of a DBMS | Data storage, retrieval and update. The DBMS must allow users to store, retrieve and update information as easily as possible, without having to be aware of the internal structure of the database. |
| 2/5 functions of a DBMS | Creation and maintenance of the data dictionary. |
| 3/5 function of a DBMS | Managing the facilities for sharing the database. The DBMS has to ensure that problems do not arise when two people simultaneously access a record and try to update it. |
| 4/5 function of a DBMS | Backup and Recovery. The DBMS must provide the ability to recover the database in the event of system failure. |
| 5/5 function of a DBMS | Security. The DBMS must handle password allocation and checking, and the "view" of a database that a given user is allowed. |
| The role of the database administrator in a typical DBMS | Maintaining the database structure. Controlling access to the database e.g assigning access rights/user names and passwords. Designing reports/queries. Keeping users informed of changes relevant to the user. Managing backups. Ensuring compliance with legislation eh DPA. |
| Facilities provided by a DBMS for end users. 1/5 MSRPC | Maintain or update tables in a DB by adding or amending existing records. |
| Facilities provided by a DBMS for end users. 2/5 MSRPC | Search the data using query language and save their query for reuse. |
| Facilities provided by a DBMS for end users. 3/5 MSRPC | Run macros - macros automate important actions by running several commands in sequence after the user has issued a single command. DBAs may create a macro to simplify some task for users, such as running several queries or reports in a sequence. |
| Facilities provided by a DBMS for end users. 4/5 MSRPC | Allows users to print information. Both tables and the results of queries can be printed. A reporting tool is often used to format the results of a query or contents of a table before printing. |
| Facilities provided by a DBMS for end users. 5/5 MSRPC | Allow users to change their password (and DBAs to reset end user passwords when they forget them) |
| How a DBMS improves the quality of the organisation's information. | Obtaining info is more efficient as there will be no data redundancy. So there will be less data in the database. Info will also have improved data integrity as there will be no data inconsistency. |
| Features the DBMS will provide for the I.T manager. | Will be able to: Modify the data model by amending its structure. Maintain the data dictionary by specifying criteria. Control access to the database by allocating access rights. |
| Features the DBMS will be able to provide for end users | End users will be able to: Insert data into tables. Delete data from tables. Run standard queries. Create reports. |
| What does a Management Information System (MIS) do? | Transforms large amounts of raw data (from a data processing system) into information which can be used to assist decision making at 3 different levels by spotting trends and patterns. Data is used by different levels of management and is from both internal and external sources. |
| Strategic level of a MIS | Top level: Senior Management Long term decisions Not immediate Decisions taken will affect the whole organisation. Overall company objectives identified and evaluated. |
| Tactical level of a MIS | Middle level: Department Heads Medium term decisions. Decisions taken will affect large groups within organisation. Responsible for implementing objectives set at Strategic level. |
| Operational Level of MIS | Lowest level: Operatives Short term decisions Decisions taken will have effect immediately on a small number of people. Small area of responsibility; usually work face to face with public. |
| External Data | Data that enters the organisation from the outside (an external source) Or data created within an organisation and then output to an external destination. Example:Competitors pricing |
| Internal Data | Data whose source and destination are within a single organisation. |
| Describe the purpose of a typical MIS | Convert data from internal and external sources into information that can be used to make effective decisions for planning, directing and controlling the activities they are responsible for. |
| MIS help managers to: 1/6 | Designed to support managers in as many of these functions as possible at different levels - operational, tactical and strategic. |
| MIS help managers to: 2/6 | Plan. In order to maximise profit. |
| MIS help managers to: 3/6 | Organise. Resources, people, space and equipment. |
| MIS help managers to: 4/6 | Coordinate. Activities of different departments. |
| MIS help managers to: 5/6 | Decision Making. Organisation, products, employees. |
| MIS help managers to: 6/6 | Control. Monitor and supervise activities of others. |
| What is the difference between a data processing system and a management information system? | DPS: deals with day to day transactions upon which a business depends, which represents the core business of the organisation. Eh involve processing. MIS: takes data from a data processing system and from external sources and turns it into useful/relevant information. |
| Limitations of using a MIS | The data input may be incorrect, out of date or not completely relevant. The MIS may not be designed correctly. It may not meet the needs of the user or the information it produces may not be what is required. May prevent managers using intuition/common sense which may be needed to resolve unexpected situations. |
| Two disadvantages of a MIS except accuracy and up to date. | Info may be poorly presented. Layout may be confusing to read. Font size may be too small. Reports may not contain all the information required. They may include irrelevant info. They may be poorly designed. The designers may have misunderstood their purpose. |
| Reasons why the MIS might fail | Might not be developed within the agreed timescale since it might have proven to be more complicated than expected. Might not have been developed within the agreed budget since it might have proven to be more complicated than expected. |
| What is a decision support system? | A DSS is software which analyses large volumes of data to identify trends and presents itself in a form which enables managers to solve unstructured problems. |
| Main features of a DSS | Part of a special type of MIS. Provides senior management with the key information they need for strategic decisions by applying different business models to data. The problems may be complex such as "what if". It may incorporate an expert system. |
| What is an expert system? | An application that carries out a task otherwise performed by a human expert, at or near the skill level of the expert. System is given knowledge s specialist would have and makes recommendations based on it. |
| Difference between data support system and expert system? | DSS makes recommendations that humans are expected to discuss, evaluate and query further. ES is expected to give the correct answer without the need for discussion. It is suitable only for certain applications where rulers can be defined. |
| Features of an expert system | Is limited to a certain area of knowledge or domain. Is based around rules, facts and principles. Can deal with fuzzy logic. Don't know, maybe. The systems reasoning can be explained to the user. It is capable of learning from experience. |
| Three components of an expert system | Knowledge Base - a store of facts, rules and principles from a given field. Inference Engine - solves a problem by applying the rules and knowledge already in the system to the facts that are entered concerning the problem. User Interface - includes menus, graphics and facilities for explaining the system's reasoning. |
| Examples of an expert system | Online help. Language translation. Gaming. Medicine. Law. |
| Why should a business not rely on a DSS alone? | Some decisions may require human intuition for which DSS cannot be programmed. May become over reliant on DSS. May not be able to make decisions if system goes down. Data used by DSS may contain errors and provide incorrect support. DSS may not have been designed properly and not support the decisions it has to make. |
| How an expert system is created | Designer will use special expert system software. Experts in the field will be questioned about how they make decisions about topic. A knowledge base will be established representing the experts knowledge. An inference engine will be designed to apply the rules. An appropriate user interface will be designed. |
| Benefits of using an expert system | Can have a wider/more up to date knowledge base. People may respond more confidently to a machine. ES can improve productivity. Individual can concentrate on dealing with problem instead of wasting time trying to figure out what the problem is. ES will produce more consistent diagnosis. Won't be affected by external distractions. |
| How is a rule base created? | An ES designer, using a shell, will question a range of experts in the field or consult textbooks or encyclopaedias about the given field. Connections will be identified. |
| Security Threats | Natural Disasters Hackers and Viruses Faulty S'ware and H'ware Unauthorised access to premises Disgruntled ex-employees Removal of data on USB Insecure communications |
| Threats to Data Security when connected to the internet 1/2 | Attack from viruses attached to emails, other files or non secure sites leading to data loss/modification. |
| Threats to Data Security when connected to the internet 2/2 | Unauthorised external access from programmers/hackers leading to unauthorised us of data, corruption of data or deletion of files. |
| How can access rights improve data security? | Each user is allocated an access level which controls the access they have to specific data files. Eg.Read Only. Access rights are held in a table (FAT). Enforced by username/password system. When a user tries to access a data file, the computer uses the table to check that they have the appropriate level of access. If they do not, access is denied. |
| Main methods of ensuring data security and privacy in a DBMS | User IDs/Passwords Limiting Logins Access Rights and Locking Audit Trails |
| Auditing and Accounting Software 1/3 | Automatically maintains a log of all database activity. In the event of data being corrupted, the changes made can be undone to restore the original data. |
| What information does auditing software record? 2/3 | The time the system was accessed, on what terminal, by whom and for how long. Changes to files eg inserting,deleting, updating of records or files. |
| How audit trails improve security of data on a network 3/3 | Every significant activity is automatically recorded. Eg Logons, accessing datafiles, accessing software. If an unauthorised/suspicious activity is suspected, the user/time/location can be identified. Can't stop problems happening, just act as a deterant and gives the opportunity to undo mistakes. |
| How does encryption improve the security of data on a network? | Data is encrypted before transmission by applying a key. The process is reversed after transmission by applying the same key. Data intercepted during transmission is meaningless (without the key) |
| Activities which take place during a typical audit trail | It records: The user name of each user logged on. The log on/log off times. The data files accessed. The software used. Other resources eg print pages Unsuccessful log ons. |
| Different Access Levels which can be used on a network. | Full Access/Read Write Access - Data can be read/updated/deleted Read and copy access - The user can edit a copy of the file. Read only Access - Data in the file can only be read, it cannot be updated/deleted. |
| A non physical measure of restricting access to a network to authorised users only | Usernames and passwords can be used. Both are required to log on. They are checked against a list of authorised users. The password is not displayed/is stared out when entered. |
| How could accounting software be used on a network? | It will record how each network user makes use of resources such as the use of processor time, the amount of external storage space required and the number of printouts. |
| How could accounting software be used on a network? 2/2 | May be for billing purposes. So that users can be charged according to the resources they use. These charges will be applied automatically. This may be for network management purposes to provide statistical data on resource usage. |
| What is a backup and recovery plan? | A self contained section of a security policy that describes how all data can be recovered in the event of a natural or man-made catastrophe. |
| Why might an organisation need a disaster Recovery plan? | To ensure that: The organisation can continue operating after a disaster e.g. earthquake. That critical data has been identified, That key functions/processes are identified, That key personnel have been identified and will continue to have access to the organisations' computer systems. An alternative location may be established where the computer system can operate until the treat/damage is over. |
| Contents of a typical disaster recovery strategy 1/2 | The strategy describes how the company will maintain its core business during a natural/criminal emergency. It includes the company's key business processes, the company's key hw/sw/communication technology/personnel. |
| Contents of a typical disaster recovery strategy 2/2 | It includes the company's continuity needs, the alternative ICT facilities, Emergency contacts/procedures, Procedure to change over to alternative facilities and Procedures to change back to original system. |
| Common Backup and Recovery Strategies | RAID, Three Generations, Incremental Backup, Full, Periodic Backup. |
| What should a backup strategy do? 1/2 | Ensure all files are backed up at specified, frequent, intervals and held securely. State how long backups are to be held. |
| What should a backup strategy do? 2/2 | State how and where files will be backed up. State the media used to perform the backups. |
| A suitable backup and recovery strategy for a real-time application? | RAID. An exact copy (called a mirror image) of all data/transactions is kept. All transactions are recorded on both systems simultaneously. The copy is stored at a remote/separate location. If the live system fails there is an instant switch over to the back up system. |
| A suitable backup and recovery plan for a batch processing application. Back up. | A complete backup would be suitable. All data files are backed up. An incremental back up is suitable. Only data that has changed is backed up. Master data should be copied just before batch processing takes place onto a portable medium and stored away from the computer system. Transactions in the batch should also be copied. |
| A suitable backup and recovery plan for a batch processing application. Recovery Plan | The master data should be restored from the backup copy. The batch of transactions should be processed again. |
| Main features of an incremental backup? | Saves only the data that has changed since the last backup. Performed at regular intervals. The backup files consist of an initial (or regular) full backup plus all incremental backup files to enable a complete restore. |
| Other sections you would find in the security policy? | The critical resources involved..Personnel/data/hw/sw. Confidentiality of data. How data protection legislation will be implemented. Acceptable use policy. Employer's and employee's responsibilities regarding copyrights/use of ICT including e-mail and the internet. |
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