16-08-2012, 05:00 PM
MICROSOFT ACCESS
ACCESS_LITERATURE.doc (Size: 41.5 KB / Downloads: 32)
INTRODUCTION:
Access is a database management system. Databases are an important part of everyday use. We use them anywhere we use computers, at home, and in the fields of medicine, education, law, business, engineering and government.
A database is a collection of data and facts that are related to a particular object or purpose, such as tracking customer orders or maintaining a music collection. If your database is not stored on a computer, or only parts of it are on the computer, you may be tracking information from a variety of sources that you have to coordinate and organize yourself.
DESIGNING A DATABASE:
Good design is a key factor of successful database building. A well designed database can lead to more efficient use of queries, forms, and reports, and can increase the reliability of the extracted information. In addition, an effectively designed database will be easier to expand as you organization’s information requirements grow and change.
Although there are guidelines to assist you in designing your database, there is no such thing as a perfect database design. Designing information systems always involves a degree of compromise. The purpose of this appendix is to provide a general overview of good database design principles. These guidelines should not be viewed as hard and fast rules, but rather suggestions for making your database design decision.
DATABASE DESIGN PROCESS:
Although there is no one correct way to create a database, there are some general steps that some professional systems developers follow. These steps generally reflect what is known as the Systems Development Life Cycle (SDLC). The SDLC breaks the task of creating a system into stages.
A variety of techniques can be employed to answer these questions. One of the best ways is to involve the future end-users of the database. A database, however, may have hundreds or even thousands of users. However, if the database is very large, you might have to consult representatives of various user groups, such as a database design committee.
WORKING WITH TABLES IN DATASHEET VIEW:
Tables are used to store data in a database. Tables can be created in two views, Table Design view or Datasheet view. In addition, you can use the Table Wizard or import a table from an external file. Records are automatically saved as you move from record to record but changes to the layout of a table (or a form) must be saved.
TABLE DESIGN VIEW:
In table design View, you must specify the fields, specify the data type for each field, assign the size for text and number fields, assign the primary key (see glossary for definition) and save the table yourself.
DATASHEET VIEW:
In data sheet view data types are very important to creating a database. There are 10 different types to choose from. The data type determines what kind of information may be entered in a field. You can always change the data type of a field after you have entered data into it. However, it may be a difficult process if the data field conflicts with the current data type (for example, changing a text field to a number field). The table below shows the specifics on each data type.