POSSIBILE SCARICARE L'INTERO SITO IN FORMATO PDF ...

Chignoli Paolo 5^Din
THE DATABASE
A database is a collection of information organized in such a way that a computer program can quickly select
desired pieces of data. You can think of a database as an electronic filing system.
ORGANIZATION OF DATABASE
Traditional databases are organized by:
- Fields;
A field is a single piece of information.
- Records;
A record is one complete set of fields.
- Files;
A file is a collection of records.
WHAT I CAN MAKE WITH A DATABASE?
With a database software you can:
- Create and maintain a database by adding, deleting, and revising records;
- Extract and list only the records that meet certain conditions;
- Sort records in ascending or descending sequence by key fields, for example alphabetically by name;
- Connect information from more than one file;
- Generate formatted reports that sort and group data;
THE CROSS-REFERENCES OPERATION
One important operation in a database is to set up files of data and to link files together, that is, cross-references
information between them.
Linked data can be searched according to certain criteria stipulated by the user. Moreover, any record in a database
can be updated without having to update it in all the linked files. This is done automatically.
DBMS
To access information from a database, you need a DataBase Management System (DBMS). A DBMS is a powerful
software that can analyze data in lots of ways. Its purpose is to make it possible to obtain meaningful information
from the data contained in the database.
Essentially DBMS is a software that allow user to communicate and execute instruction with a database.
DATABASE APPLICATIONS
A few examples of database applications include:
- Details of the books held in a library giving author, title and subject of each book;
- Name and address of a firm’s customers sorted by location and interest;
- Details of the items stored in a warehouse, giving location, cost, number currently in stock; and supplier.
Items out of stock can be highlighted;
- Details of student and teachers in a school to generate a timetable and class group;
EXAMPLE OF DATABASE
NAME BIRTHDATE ADDRESS
Burton C. 1975, 12 27 4, Grey St.
Greenleaf S. 1947, 4 21 31, Quincy Lane
Mahoney K. 1950, 1 30 71, Lexington Av.
Parker L. 1981, 12 30 128, Lincoln Rd.
Parker S. 1964, 6 16 7, Campbell Rd.
White B. 1982, 11 21 4, Colnbrook Park
White R. 1944, 5 14 27, Broadwick Av.
White T. 1951, 7 8 307, Commercial St.
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