A database management package or database management system (DBMS) is a software package used to set up, or structure, a database. It is also used to retrieve information from a database. The top part of the figure is a menu. Popular database management programs include dBASE, Paradox, and FoxPro. Database management packages have different features, depending on their sophistication.
Features of Database Management Packages
- Retrieve/Display: A basic feature of all database programs is the capability to locate records in the file quickly. The program can search each record for a match in a particular field to whatever data users specify. The records can then be displayed on the screen for viewing, updating, or editing.
- Program Control Languages: Most people using a database management program can accomplish everything they need to do by making choices from the menus. Many database management programs include a programming control language so that advanced users can createsophisticated applications.
- Customized Data-Entry Forms: A person new to the database program may find some descriptions for fields confusing. For example, a field name may appear as “CUSTNUM” for “customer number.’ However, the form on the screen may be customized so that the expression “Enter the customer number” appears for “CUSTOM.” Fields may also be rearranged on the screen, and boxes and lines may be added.
- Calculate/Format: Many database programs contain built-in math formulas. In the office, for example, users can use this feature to find the highest or lowest commissions earned. Users can calculate the average of the commissions earned by the sales force in one part of the country. This information can be organized as a table and printed out in a report format.
- Sort: Database management packages make it easy to change the order of records in a file. Normally, records are entered the database in the order they occur. There are many ways users can quickly rearrange the records in the file, such as by employees’ last name or by their social security number.
- Professional-Looking Reports: A custom-report option enables users to design the elements users want in a report. Examples are the descriptions appearing above columns and the fields users wish to include. Users can even add graphic elements, such as a box or line, so that the printed report has a professional appearance.
- Program Control Languages: Most people using a database management program can accomplish everything they need to do by making choices from the menus. Many database management programs include a programming control language so that advanced users can create sophisticated applications.
BASIC TASK OF DBMS PACKAGES
Most DBMS packages can perform four primary tasks:
- Database Development: Define and organize the content, relationships, and structure of the data needed to build a database.
- Database Interrogation: Access the data in a database for information retrieval and report generation. A user can selectively retrieve and display information and produce printed reports and documents.
- Database Maintenance: Add, delete, update, correct, and protect the data in a database.
- Application Development: Develop prototypes of data entry screens, queries, forms, reports, and labels for a proposed application.
BASIC DATABASE TERMINOLOGIES
1) Field: A field contains an item of data; that is, a character, or group of characters that are related. For instance, a grouping of related text characters such as “John Smith” makes up a name in the name field. For each person, they must identify the name, address, city, state, zip code and telephone number. A field would be established for each type of information in the list. The name field would contain all of the letters of the first and last name. The zip code field would hold all of the digits of a person’s zip code, and so on. In summary, a field may contain an attribute (e.g ., employee salary) or the name of an entity (e.g ., person, place, or event).
2) Character: A character is the most basic element of data that can be observed and manipulated. Behind it are the invisible data elements we call bits and bytes, referring to physical storage elements used by the computer hardware. A character is a single symbol such as a digit, letter, or other special character (e.g ., $, #, and ?).
3) Record: A record is composed of a group of related fields. As another way of saying it, a record contains a collection of attributes related to an entity such as a person or product. Looking at the list of football supporters, the name, address, zip code and telephone number of a single individual would constitute a record. A payroll record would contain the name, address, social security number, and title of each employee.
4) Key: In order to track and analyze data effectively, each record requires a unique identifier or what is called a key. The key must be completely unique to a particular record just as each individual has a unique social security number assigned to them. In fact, social security numbers are often used as keys in large databases. You might think that the name field would be a good choice for a key in a mailing list. However, this would not be a good choice because some people might have the same name. A key must be identified or assigned to each record for computerized information processing to function correctly. An existing field may be used if the entries are entirely unique, such as a social security or telephone number. In most cases, a new field will be developed to hold a key, such as a customer number or product number.
5) Database File: A database file is defined as a collection of related records. A database file is sometimes called a table. A file may be composed of a complete list of individuals on a mailing list, including their addresses and telephone numbers. Files are frequently categorized by the purpose or application for which they are intended. Some common examples include mailing lists, quality control files, inventory files, or document files. Files may also be classified by the degree of permanence they have. Transition files are only temporary, while master files are much more long-lived.