Database

Preview

1. What is a database, and what purpose does it serve in software development?
2. What are the main components of a database, and how do they interact with one another?
3. What data modeling techniques can be used to create a database schema, and what criteria should be considered in selecting an appropriate one?
4. What are the common types of database management systems, and what are their advantages and limitations?
5. What is normalization in database design, why is it important, and what are the various normal forms that can be used to achieve it?

Explain

A database is a collection of data that is organized in a specific way, making it easy to access, manage, and update. It typically consists of tables that contain related information and can be searched and sorted to find specific data. One example of a database is an online retail store’s inventory system, where each product is listed in a table with information such as price, quantity, and description. This data can be easily accessed and updated, allowing the store to keep accurate and up-to-date records of their inventory.

Keypoint

• A database is a collection of organized data that can be easily accessed, managed, and updated.
• It is typically used to store large amounts of related information, such as customer data, financial records, or product inventories.
• A database usually includes multiple tables, each containing specific types of data.
• Data is organized and structured using a predetermined schema or data model.
• Relational databases are the most common type, where tables are linked to each other through common fields or keys.
• SQL (Structured Query Language) is the most commonly used language for interacting with relational databases.
• A database can be managed by software called a database management system (DBMS), which handles tasks like creating, optimizing, and securing data.
• Backups and recovery procedures are crucial to ensure data is not lost or corrupted.
• Properly designed databases can improve efficiency, accuracy, and security in various industries, including healthcare, finance, education, and government.

Review

1. What is an index in a database?
   Answer: An index is a database structure that improves the performance of searching, sorting, and filtering data by creating a list of pointers to the location of the data on disk.

2. What is the difference between a primary key and a foreign key?
   Answer: A primary key is a column or a set of columns that uniquely identifies each row in a table, while a foreign key is a column or a set of columns that refers to the primary key of another table, creating a relationship between the two tables.

3. What is a database transaction?
   Answer: A database transaction is a sequence of database operations that are treated as a single unit of work, ensuring that all operations are completed successfully, or none of them are carried out.

4. What is normalization in database design?
   Answer: Normalization is the process of organizing data in a database to minimize data redundancy and improve data integrity by dividing larger tables into smaller tables and defining relationships between them.

5. What is a trigger in a database?
   Answer: A trigger is a special type of stored procedure that automatically executes in response to a specific change in the database, such as the insertion, update, or deletion of data. Triggers can be used to enforce business rules, update related data, or log changes to the database.