Lessons 20–21 · 2 lessons · N. I. Taylaqov (general editor), A. B. Akhmedov, M. D. Pardayeva, A. A. Abdug‘aniyev, U. M. Mirsanov. Informatics and Information Technologies, Grade 10, 1st edition. “Extremum-Press”, Tashkent, 2017
21
Database management systems
Textbook: pp. 45–47
GoalStates the tasks and examples of a database management system (DBMS) and tells a DBMS from Excel.
New words
database management system: software for creating, filling, searching and protecting a database · MOBT (DBMS)SQL: the standard query language of relational databases · SQLuser right: the permission to read or change certain data · foydalanuvchi huquqibackup: a saved copy of a database used to restore data · zaxira nusxa
Explanation
Special programs are needed to create, fill, search and jointly use a database: they are called database management systems (DBMS). A DBMS describes the structure of the data and provides data entry and change, searching, user rights and backups. In a good database the data do not depend on the program that uses them, and no separate program has to be written to find the data needed, because a query language (SQL) is used. DBMS examples are MS Access, LibreOffice Base, SQLite, MySQL, PostgreSQL, Firebird, Oracle and SQL Server; most of today’s DBMS are relational. An Excel table is convenient for calculations, but many linked tables, many users and the management of rights are the job of a DBMS. Databases that collect personal data are protected with passwords, and their processing is subject to Uzbekistan’s law on personal data (2019).
Worked examples
A school library: 300 books and 5 tables (books, readers, loans, authors, publishers). Both the librarian and the director see the data, but only the librarian has the right to change them. A DBMS provides this through rights, while in an ordinary table it is difficult.
An online shop website: product, order and customer data are kept in a DBMS on a server (for example MySQL or PostgreSQL). A user places an order through a form on the page, the site sends a query to the DBMS, and the database returns the records needed. A backup is made every day.
Class activity
“DBMS or Excel?”: situations are read out (family expenses, bank customers, a class marks table, airport flights); groups say which tool to choose and why.
Practice
1
What is a DBMS and what is it for?
A software system for creating, filling, searching, protecting and jointly using a database.
2
Which of MS Word, MS Access and MS PowerPoint is a DBMS?
MS Access
3
Name three DBMS.
For example: MS Access, MySQL, PostgreSQL (or SQLite, LibreOffice Base).
4
Why must backups of a database be made regularly?
If a device breaks, data are deleted or a virus attacks, the data can be restored.