ITC114

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  • Data is a corporate asset. Never really considered an asset because: - there was so much of it. - data was not as critical in that quick responses were not required. This changed with computers .... Data can be translated into Information which is used to make decisions . A critical success factor of an organisation is to manage data How do we access the value of the data: - how much would be lost if the database was lost?
  • The data-information-decision cycle will improve with the incorporation of a DBMS . It is the enduser who must analyse the data to produce the information that is later used in decision making. Data stored in the database constitutes the raw material for the creation of information eg. it may generate graphs or tables.
  • Information/data : - needs to be timely, concise, relevant, accurate
  • DBA will implement who has got access and who does not have access to data Security is controlled by the DBA – it will include: Password and encryption Views Such security is added added feature to the normal DBMS DBA must ensure that the database is secure .
  • In this example the security of the standard DBMS is extended to include additional DBA security features.
  • The capacity of the storage devices can become overloaded – taxed to the extent that the performance of the database can become a problem. Unless data that is no longer required is somehow removed then the database will simply continue to grow. It is good policy to remove data that is no longer required – however it still may need to be retained for later use. This can include government regulation, auditing, customer requirements. The process to overcome this problem is to archive it. It is simply : a storage area that is not accessed on a regular basis Does not require the access speed requirements of the main corporate database Needs to be kept in a safe location Typically the archive is a mass storage device. It could be a disk, tape, CD or DVD It is best to check to ensure that archives can be read back into the mainstream data.
  • - managerial side - careful planning, - organisational structure may have to be changed to accommodate the introduction - new staff - management need to be committed. - technology - selecting the most appropriate system - appropriately qualified staff, hardware , software etc - cultural side - change - managing this. Position of the database administrator - in reality it is often put under the person showing the greatest interest - depends totally on the organisation - depends on how serious the organisation is?????- what do you think you are going to do walk into an org and say you have the position in the wrong spot. - it needs to be seen as coordinating role in the organisation. - often a situation will participate a particular direction eg. distributed databases. OO LANs and PC prolification
  • Database Administration TOOLS : - becoming more sophisticated - Whitten called it a Project Dictionary - you must be able to access the data dictionary in the same way as you would the actual data - therefore can use SQL - the only difference is that the table names usually commence with SYS (not a standard). - no standard to a DD but the more it supports the DBMS the better.
  • Database Administration TOOLS : b. CASE tools - - what is the future for CASE? - in theory they support the SDLC - enforce standards - this is its greatest strength - EXCELERATOR is the a commercial CASE package - components graphics, screen designer, DD, analysis, program generator.
  • GANNT chart - named after the inventor of the chart is a bar chart that shows the phases or tasks on the left side of the chart and units of time across the top. They will show both the estimated and the actual time to give a clear indication of how the project is proceeding – that is planned performance against actual. PERT chart – Program Evaluation and Review Technique – is used to estimate, schedule and control a network of independent tasks shown by arrows and nodes or circles in terms of time. IT particularly shows the order that the tasks must be performed – that is which one must be performed the next. It is based on the critical, or longest time, path.
  • ITC114

    1. 1. ITC114 <ul><li>Database Administration </li></ul>
    2. 2. Objectives <ul><li>At the completion of this lecture you should be able to : </li></ul><ul><li>Describe and contrast the technical & managerial roles of the Database Administrator. </li></ul><ul><li>Explain the role of the data dictionary. </li></ul><ul><li>Outline the role of CASE tool in management of a database. </li></ul><ul><li>Describe the requirements for the successful implementation of a data administration strategy. </li></ul>
    3. 3. Database Administration <ul><li>Data is a corporate asset. </li></ul><ul><li>Data is a resource to be translated into information. </li></ul><ul><li>To maximise on the value of data, managers must understand the value of information (processed data) </li></ul><ul><li>The responsibility for supervising both the database and the use of the DBMS resides with the database administration . </li></ul>
    4. 4. Data-Information Decision Cycle Knowledge Information Actions Decision making User Data interprets used in that is the basis of converted triggers generates more analysis
    5. 5. What does a DBMS do? <ul><li>ensures data is processed according to requirements – integrity constraints. </li></ul><ul><li>distributes data & information in a timely manner. </li></ul><ul><li>ensures the security of the data. </li></ul><ul><li>Maintains data independence – allows changes in the structure of the database without the applications being affected. </li></ul><ul><li>supports managerial decision making at all levels. </li></ul><ul><li>Allows for the replication of data at different locations. </li></ul><ul><li>Provide facilities to recover the database in the even of damage to the database. </li></ul>
    6. 6. Managerial Decision Making Levels Operational managemt Middle managemt Top managemt DBMS Database Database’s predominant role to support managerial decision making at all levels.
    7. 7. A DBMS is a tool to manage data. <ul><li>DBMS must be properly managed from: </li></ul><ul><li>Technological side </li></ul><ul><ul><li>involves selecting, installing, configuring & monitoring of DBMS. Requires approximately technical skills. </li></ul></ul><ul><li>Managerial side </li></ul><ul><ul><li>DBMS does not guarantee a good information system, it still requires good management and organisational support. </li></ul></ul><ul><li>Cultural side </li></ul><ul><ul><li>can create resistance as involves change. e.g. data ownership will be shared, value, accuracy, security, privacy all issues. </li></ul></ul>
    8. 8. Role of DBA versus Data Administrator <ul><li>Data Administrator </li></ul><ul><li>Responsible for developing the enterprise data model plus the maintenance of data definitions and standards. </li></ul><ul><li>Database Administrator (DBA) : </li></ul><ul><li>A technical and managerial function responsible for all aspects of the physical database analysis and design plus including such as its performance, the security, and backup and recovery. </li></ul>
    9. 9. More on the data administrator <ul><li>Data Administrator (DA) provides a global view of the organisation’s data (manual & computerised). The role could be consumed by the DBA but it typically is a lower managerial level compared to the DBA. </li></ul><ul><li>Responsibilities include issues of: </li></ul><ul><li>determine the data requirements of the organisation. </li></ul><ul><li>data consistency & integrity. </li></ul><ul><li>highlighting data as a corporate resource. </li></ul>
    10. 10. Career path to be a DBA Programmer Analyst Programmer Project Leader / DA Database Administrator
    11. 11. Role of Database Administrator (DBA) <ul><li>Database Administrator </li></ul><ul><li>is a both a technical and a management function responsible for the physical database support. </li></ul><ul><li>The DBA is charged with all aspects of a DBMS, including selection and management. </li></ul><ul><li>basically responsible for supervising the database and the use of the DBMS. </li></ul><ul><li>Responsibilities & skills can be broken into </li></ul><ul><ul><li>managerial. </li></ul></ul><ul><ul><li>technical. </li></ul></ul>
    12. 12. Management qualities of a DBA <ul><li>ability to be able to effectively liaise with end-users. </li></ul><ul><li>be able to develop policies and procedures (standards). </li></ul><ul><li>Skills in: </li></ul><ul><ul><li>planning </li></ul></ul><ul><ul><li>analysis, design, implementation, testing procedures </li></ul></ul><ul><ul><li>data security, privacy and integrity. </li></ul></ul><ul><ul><li>backup & disaster recovery procedures. </li></ul></ul><ul><li>The qualities of the DBA lie between the technical and the managerial activities </li></ul>
    13. 13. Technical Role of the DBA <ul><li>Generic Skills ……… </li></ul><ul><li>Specific tasks of the DBA in selecting DBMS: </li></ul><ul><ul><li>choose the DBMS model. </li></ul></ul><ul><ul><li>storage capacity, add-on support, security and integrity, backup-recovery, concurrency controls, performance, database admin support, H/W requirements, cost, training support. </li></ul></ul><ul><ul><li>data loading, conversion, access plan. </li></ul></ul><ul><ul><li>affording access rights to users. </li></ul></ul>
    14. 14. Access privileges and security <ul><li>Access </li></ul><ul><ul><li>Users should access the database only in ways in which they are entitled. </li></ul></ul><ul><ul><li>Defined by the DBA </li></ul></ul><ul><li>Security </li></ul><ul><li>Protection of data against accidental or intentional loss, destruction or misuse. Can include: </li></ul><ul><ul><li>Human error </li></ul></ul><ul><ul><li>Software failure </li></ul></ul><ul><ul><li>Hardware failure </li></ul></ul>
    15. 15. Security issues …. <ul><li>Theft of Information </li></ul><ul><li>Improper data access </li></ul><ul><ul><li>Privacy issues </li></ul></ul><ul><ul><li>Confidentiality </li></ul></ul><ul><li>Unauthorised modification of data </li></ul><ul><li>Unauthorised destruction of data </li></ul>
    16. 16. What are some of the security issues … <ul><li>Authorisation </li></ul><ul><ul><li>Access restrictions ensure that the database is secure. </li></ul></ul><ul><ul><li>Effective password protection is critical however …. </li></ul></ul><ul><ul><ul><li>Can be shared </li></ul></ul></ul><ul><ul><ul><li>Can be written down and copied </li></ul></ul></ul><ul><ul><ul><li>Automatically login can be employed </li></ul></ul></ul><ul><ul><ul><li>Unencrypted passwords can be intercepted. </li></ul></ul></ul><ul><li>Alternatives </li></ul><ul><ul><li>Biometrics </li></ul></ul><ul><ul><li>Digital certificates </li></ul></ul>
    17. 18. Other duties of the database administrator <ul><ul><li>enforcement of standards – programming, naming conventions, testing procedures, H/W upgrade standards, change control ….. </li></ul></ul><ul><ul><li>maintaining the data dictionary </li></ul></ul><ul><ul><li>provide assistance and support during the conceptual, logical and physical design. </li></ul></ul><ul><ul><li>database design support. </li></ul></ul><ul><ul><li>testing and evaluation of the database. training </li></ul></ul>
    18. 19. The database administrator can use a checklist to assist in the selection and the evaluation of the DBMS
    19. 20. The DBA can evaluate the purchase of a DBMS in terms of the categories lists in this figure.
    20. 21. and yes …. there is more ….
    21. 22. Database Administration Strategy <ul><li>depends on the organisation. </li></ul><ul><li>can be referred to by different names. </li></ul><ul><li>need to link it to the corporate strategy. </li></ul><ul><li>it is a framework of management/ support for organisations data (asset). </li></ul>
    22. 23. Planning for a disaster … <ul><li>A DBA must plan for disasters: </li></ul><ul><ul><ul><li>Intentional – unauthorised access </li></ul></ul></ul><ul><ul><ul><li>Accidental – disk problem, power outage, computer malfunction, flood or some other natural disaster </li></ul></ul></ul><ul><li>DBA must take an active role in a disaster recovery plan </li></ul><ul><li>So how do you plan for a disaster? </li></ul><ul><li>you must know the value of your data …. </li></ul><ul><li>for what period can your organisation function without access to the data? </li></ul><ul><li>The DBA must be proactive in developing a disaster recovery plan. </li></ul>
    23. 24. Disaster Recovery Plan <ul><li>Typically a journal or a file will be accessed to obtain information about the state of the database just before the disaster. </li></ul><ul><li>PC-based DBMS machines lack facilities to maintain an effective journal  limited recovery is possible. </li></ul><ul><li>Alternative is to add additional DBMS features to support the database </li></ul>
    24. 25. A journal records changes made to the database – basically creates an audit trail To recover the database the back copy is recovered first, and then the journal is used to simulate changes since the last backup. How does the journal operate?
    25. 26. What is the purpose of an archive? <ul><li>Archiving is the process of ‘off-loading’ documents and records to an alternate disk space. </li></ul>
    26. 27. Backup facilities <ul><li>Ensure automatic dump of the database </li></ul><ul><li>Periodic – nightly, weekly, monthly </li></ul><ul><li>Backup – completed at specific time – may require shut down of the part/whole system. </li></ul>
    27. 28. So what happens if the database fails …. <ul><li>Aborts transaction – typically rollback </li></ul><ul><li>Incorrect data – rollback </li></ul><ul><li>System failure – prefer approach – use redundant system </li></ul><ul><li>Database destruction – again switch to redundant system – otherwise roll forward </li></ul>
    28. 29. Where does the position of DBA fit? <ul><li>initially was a functional responsibility. </li></ul><ul><li>depends on the organisation. </li></ul><ul><li>Should be a very high managerial position. </li></ul>
    29. 30. Resources of the DBA <ul><li>Data Dictionary </li></ul><ul><li>Case tools </li></ul><ul><li>Project Management tools </li></ul><ul><li>Decision Support Systems </li></ul>
    30. 31. Resources of the DBA <ul><li>The Data Dictionary </li></ul><ul><li>- stores the definitions and relationships of the DBMS. </li></ul><ul><li>Classified by: </li></ul><ul><li>stand-alone or integrated. </li></ul><ul><li>active or passive. </li></ul>
    31. 32. Data Dictionary <ul><li>A data dictionary is a comprehensive document that defines the everything about a system. </li></ul><ul><li>A DD not only includes the actual data but also metadata - data about the database e.g. </li></ul><ul><ul><li>table definitions </li></ul></ul><ul><ul><li>indexes </li></ul></ul><ul><ul><li>who created the database </li></ul></ul><ul><ul><li>valid users </li></ul></ul><ul><ul><li>valid applications that can access the DBMS </li></ul></ul><ul><ul><li>Authorisations / security </li></ul></ul>
    32. 33. More on the data dictionary <ul><li>no standard to a DD but the more it supports the DBMS the better. </li></ul><ul><li>Some authors may refer to it as a Project Dictionary </li></ul><ul><li>you must be able to access the data dictionary in the same way as you would the actual data - therefore can use SQL e.g. </li></ul><ul><li>SELECT NAME, CTIME FROM SYSTABLES WHERE CREATOR = “ATKINSON” </li></ul>
    33. 34. Resources of the DBA <ul><li>2. CASE tools </li></ul><ul><li>(Computer Aided Software Engineering) </li></ul><ul><li>Can be classified as: </li></ul><ul><li>Front-end CASE tools (support for planning, analysis & design) . </li></ul><ul><li>Back-end CASE tools (support for coding & implementation) . </li></ul>
    34. 35. Functions of a CASE tool <ul><li>Graphics – in particular model drawing facilities </li></ul><ul><li>Screen designers and report generators </li></ul><ul><li>An integrated repository (DD) </li></ul><ul><li>An analysis component to provide an automated check on system consistency, syntax and completeness </li></ul><ul><li>A program documentation generator . </li></ul><ul><li>Central to a CASE tool is the central repository, basically the DD, to integrate all the data. </li></ul>
    35. 36. Resources of the DBA <ul><li>3. Project Management resources / skills </li></ul><ul><li>Basically requires the DBA to coordinate, direct, control and manage the timing of any project work. Software to do this can include </li></ul><ul><ul><li>MS Project </li></ul></ul><ul><ul><li>GANNT Charts </li></ul></ul><ul><ul><li>PERT chart </li></ul></ul><ul><ul><li>ITC301 </li></ul></ul>
    36. 37. Resources of the DBA <ul><li>4. Decision Support Systems </li></ul><ul><li>DSS is software the DBA to help make the decision maker make decisions. </li></ul><ul><li> - Alternatively it could be Executive Information Systems (EIS) </li></ul><ul><ul><li>- Assisted through use of data warehousing technology </li></ul></ul>

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