Database Management Systems

Data File and Database System

• A database system stores all data in files, including lists of entities, their attributes, and relationships between entities.

Advantages of Database System

• Database systems allow for getting more information from the same amount of data.
• They enable sharing data among multiple users.
• They balance conflicting requirements by imposing structure on the database.
• They reduce redundancy by saving data elements in only one place, conserving storage space and simplifying updates.
• They facilitate consistency by reducing redundancy.
• They improve integrity by enforcing rules and constraints on data.
• They provide data independence, allowing for changes to the database structure without reentering data.

Database Management System (DBMS)

• A DBMS is a software solution that allows users to store, retrieve, and produce reports from data.
• A DBMS can perform functions such as update, insertion, and deletion.

Basic Database Terms

• An entity is something that you want to store data about, often referred to by a plural noun (e.g., customers, accounts, employees).
• An attribute is a characteristic of an entity, also known as a field, column, or property.
• A record is all the data about one instance of an entity.
• A relationship is an association between entities in a database (e.g., customers and sales reps).

Limitations of File Systems

• File systems take a long time to create, learn, and use.
• They take a long time to harvest information from.
• Maintenance is difficult.
• They have minimal security, requiring physical presence.
• They do not support features commonly found in DBMS systems.

File System vs. DBMS

• File systems do not support structural independence, requiring changes to programs when file structure changes.
• DBMS systems support structural independence, allowing for changes to file structure without changing programs.