Database Fundamentals PDF

What is a Database - A database is system that allows us to store data in a structured way using tables and fields, and gives us various means of access to to the data. What is the difference between a data and information? - Data is a collection of facts that are meaningless on their own whereas i...

What is a Database - A database is system that allows us to store data in a structured way using tables and fields, and gives us various means of access to to the data. What is the difference between a data and information? - Data is a collection of facts that are meaningless on their own whereas information puts data into clear understandable context. What is the difference between a database and a spreadsheet? - Whilst spreadsheets may primarily be used to manipulate data using functions and formula to perform calculations and statistics, whereas databases are primarily used to store data What is the difference between a database and an information system? - A database will contain data that is used by information systems where-as the information system comprises the complete system, furthermore may present the data from the database in a way in which it becomes information. DBMS - Database Management Systems refer to software used to manage the database, for a single database this could include various software and applications the form a database management system SQLite. The DBMS should provide an interface for data manipulation, it should provide some form of data security and should have some build in data validation methods. THE NEED FOR DATABASES ○  ata organisation: D ○ Data integrity: ○ Data security: ○ Scalability: ○ Performance: ○ Data sharing: DDL (Data Definition Language) - DDL or Data Definition Language actually consists of the SQL commands that can be used to define the database schema. List of DDL commands: CREATE: This command is used to create the database or its objects (like table, index, function, views, store procedure, and triggers). DROP: This command is used to permanently delete objects from the database. ALTER: This is used to alter the structure of the database. Delete: It will help us to delete a single record or a complete table but the structure of the table remains same. DML(Data Manipulation Language) - The SQL commands that deal with the manipulation of data present in the database List of DML commands: INSERT: It is used to insert data into a table. UPDATE: It is used to update existing data within a table. DELETE: It is used to delete records from a database table.