The world generates an enormous amount of data from almost every aspect of life; school records, credit cards, store merchandise, telephone systems and web sites, among others. Some time ago, manual effort was used to track and report this information. Today, electronic database management systems manage this information.
By definition, a database is structured collection of logically related data that is stored so that it can easily be accessed / retrieved. Logically related data comprises entities, attributes, and relationships of an organization’s information. Examples of databases include: Phone Address Book, Business Customer Lists, Club Membership Lists, Company’s Employee
Database, The library database, Video Library, etc.
A manual database is one that is not computerised – i.e. not available in electronic format. A telephone directory, an organiser or printed address book are examples of manual databases.
An electronic database is one that is computerised, and can be accessed/manipulated using computer applications.
A Database Management System (DBMS) is a software program used to create and manage an electronic database. It provides users with tools used to add, delete, access, modify, and analyze data stored in one location. Examples of DBMS software include: Microsoft Office Access, dBase, SQL Server, Oracle, MySQL, Informix, DB2, Paradox, FoxBase, FileMaker Pro, Lotus Approach, etc. A DBMS typically have the following features:
- Logical Data structures / Objects – such as tables, forms, queries and reports, used to store and manipulate structured data.
- A query language (such as SQL) used to manipulate or extract data.
- Filter Commands- that display data which satisfy certain conditions.
- Data validation commands: that ensure the integrity of data entered and stored in the database.
- Relationships/associations between data objects/ tables.
- Sort commands/tools that arrange data values in a certain order.
- Import/Export commands to enable sharing of data between the database program and other programs that use similar structured data.
- Built-in functions (similar to those available in spreadsheet applications) that simply calculations. •
Advantages of Electronic Databases over Manual databases
- Electronic databases store very large amounts of data
- Electronic databases allow easy input and editing of data
- Electronic databases enable automatic updating and recalculating of data
- Electronic databases make it easier to query, search, filter and retrieve required data.
- Electronic databases format, arrange and present information in customizable ways
- Electronic databases can easily share the information with other software applications/programs
- Electronic databases allow centralised use of information amongst many users over a network and therefore reduce duplication, e.g in banks.
- Data is validated before it is entered in electronic databases. Errors created during data entry are minimized
- Many built-in functions are available to in Electronic databases simplify calculations.
- Improved security: Database security is the protection of the database from unauthorized users. Without suitable security measures, integration makes the data more vulnerable than file-based systems. However, integration allows the Database administrator to define, and the DBMS to enforce, database security. This may take the form of user names and passwords to identify people authorized to use the database.
- Economy of scale: Combining all the organization’s operational data into one database, and creating a set of applications that work on this one source of data, can result in cost savings.
- Increased concurrency: Many DBMSs manage concurrent database access, ensuring that two or more users are allowed to access the same file simultaneously, without interfering with each other, or resulting in loss of information or its integrity.
- Improved backup and recovery services: modern DBMSs provide facilities to minimize the amount of processing that is lost following a failure.
Disadvantages of relying on electronic databases as compared to manual databases
- Complexity: The provision of the functionality we expect of a good database makes it complex to set up. Database designers, database administrators, and end-users must understand this functionality to take full advantage of it. Failure to understand the system can lead to bad design decisions, which can have serious consequences for an organization.
- Cost of setting up a database: The cost of setting up an electronic database varies significantly, depending on the hardware, software and functionality required.
- The need for conversion & difficult transition: This includes the cost of converting existing applications to run on the new DBMS and hardware plus the cost of training staff to use these new systems, and possibly the employment of specialist staff to help with the conversion and running of the system.
- Performance: Typically, a file-based system is written for a specific application, such as invoicing. As a result, performance is generally very good. However, the DBMS is written to be more general, to cater for many applications rather than just one. The effect is that some applications may not run as fast as they used to.
- Higher impact of a failure: The centralization of resources increases the vulnerability of the system. Since all users and applications rely on the availability of the DBMS, the failure of certain components can bring all operations to a halt.
NB: Watch out for a class presentation with comprehensive notes having both practical and theoretical aspects of databases completely compiled as per the NCDC Sub ICT syllabus, available on my eshop.
During the upcoming Capacity Development Workshop (CDW) scheduled for 6th and 7th May, 2019 at Kololo SS, a new compilation of UPDATED NOTES will be included on the resource DVD which will be given to every participant free of charge. To attend the CDW, register at CDW.ictteachersug.net. Few slots left!
+256776960740 / +256706060740