Governs interactions between application programs, input data and the database itself i.e.
#Uses of database management system pdf update
#Uses of database management system pdf software
Database management systems (DBMS) P301 and 311 A DBMS is application software that lets you create, organise, update, store, and retrieve data from a single database or several databases. A Relational Database is designed to handle data in TABLE form and a single database is likely to contain a number of separate but related, tables. The records can only be accessed in a limited number of ways, and the number of fields in a record will be limited. The Database Approach p.300 Flat-File or card index Databases - contain one file. INVESTMENT-AC TABLE INVESTMENT-AC ID Account Balance LOAN-AC TABLE LOAN-AC ID Interes t Rate Loan Balance Loan PeriodĬURRENT AC TABLE CURRENT-AC ID Account Balance SAVINGS -AC TABLE SAVINGS-AC ID Account Balance data available to multiple applications and users CUSTOMER TABLE CUSTOMER ID Cus tomer Name NI Number Address Savings-Ac ID Loan-Ac ID Current-Ac ID Investment-Ac ID.data is combined into a single customer database (pooled data).Customer NI number Address Savings Account Number BalanceĬustomer NI number Address Loan Account Number Interest Rate BalanceĬustomer NI number Address Current Account Number BalanceĬustomer NI number Address Investment Account Number Interest Rate Balance Costs to run the system are driven up because of clerical time needed to input data and check for errors, it is very difficult to combine information. Information is duplicated throughout the system updates may occur at different times, some errors remain undetected. there are no restrictions on who can see what.Ī Bank using a Flatfile Different Information Systems have grown up over time, often with their own software programs and ways of doing things. updates to information and changes to file structure can be unweildy. Note the issues that remain given in P.300 Unproductive maintenance i.e. Similarly if different departments want to access data this would be very awkward. in this system a summary of account balances in each separate account would require separate reports for each open account or cutting and pasting into a wordprocessor file – not a satisfactory state of affairs. The problems already stated show that information can be out of date, can have different values in different parts of the system, can be inaccurate etc. this is the quality by which information from the sysstem can be trusted. effort required to change from 3-digit STD to 4-digit STD may be very difficult. In the bank imagine cases where any change in data format or structure requires a change in all the programs that access the data. (Data dependence refers to the close relationship between data stored in files and the specific software programs needed to update and maintain those files). information is duplicated in each system and may be updated in most systems but not necessarily in all – the savings account and loan account may have different addresses for a particular customer. Data inconsistency will become a problem e.g. Errors are generated, time entering data is wasted, computer resources are needlessly taken up and updates can be an enormous problem. Customer Name, NI number, Address is present in several different files on several different systems. Data redundancy is found- the presence of duplicate data in multiple data files e.g. Problems when using a flat-file approach (see the attached bank example) p.300 1. Recall the relevant advantages of a client/server database over a non-client/server database. (Chapter 56) Explain the concept of a client/server database. Explain the concept of entity relationships and data normalisation. (Chapter 57) Explain what is meant by data consistency, data integrity, data redundancy and data independence. (Chapter 55, 57) Explain the role of the database administrator. A2 MODULE 5 (ICT5) 14.3 DATABASE MANAGEMENT CONCEPTSĮxplain the purpose of a database management system (DBMS).