Database Concepts

• What is DATA?
• Data is a collection of a distinct small unit of information.
• It can be used in a variety of forms like text, numbers, media, bytes, etc.
• it can be stored in pieces of paper or electronic memory, etc.
• Word 'Data' is originated from the word 'datum' that means 'single piece of information'.
• In computing, Data is information that can be translated into a form for efficient movement and processing.
• Data is interchangeable.
• What is Database?
• A database is an organized collection of data, so that it can be easily accessed and managed.
• A database is an organized collection of structured information, or data, typically stored electronically in a computer system.
• A database is usually controlled by a database management system (DBMS).
• You can organize data into tables, rows, columns, and index it to make it easier to find relevant information.
• The main purpose of the database is to operate a large amount of information by storing, retrieving, and managing data.
• There are many databases available like MySQL, Sybase, Oracle, MongoDB, Informix, PostgreSQL, SQL Server, etc.
• A cylindrical structure is used to display the image of a database.

• Types of Databases:
• Relational database:
• Relational Databse became dominant in the 1980s.
• Items in a relational database are organized as a set of tables with columns and rows.
• Relational database technology provides the most efficient and flexible way to access structured information.

• Object-oriented database:
• Information in an object-oriented database is represented in the form of objects, as in object-oriented programming.

• Distributed database:
• A distributed database consists of two or more files located in different sites.
• The database may be stored on multiple computers, located in the same physical location, or scattered over different networks.

• Data warehouse:
• A central repository for data, a data warehouse is a type of database specifically designed for fast query and analysis.

• NoSQL database:
• A NoSQL, or nonrelational database, allows unstructured and semi structured data to be stored and manipulated.
• NoSQL databases grew popular as web applications became more common and more complex.

• Graph database:
• A graph database stores data in terms of entities and the relationships between entities.

• Cloud database:
• A cloud database is a collection of data, either structured or unstructured, that resides on a private, public, or hybrid cloud computing platform.
• There are two types of cloud database models: traditional and database as a service (DBaaS). With DBaaS, administrative tasks and maintenance are performed by a service provider.
• Structure of Database:
• The structure of a database defines how data is organized, stored, and managed.
• Here’s an overview of the main components and concepts that define the structure of a typical relational database.
• Data:
• Data is the raw information stored in the database.
• It can be numbers, text, dates, or binary data like images and files.
• Database Management System (DBMS):
• A DBMS is software that allows users to define, create, maintain, and control access to the database.
• Examples include MySQL, PostgreSQL, Oracle, and Microsoft SQL Server.
• Table:
• Tables are the primary storage objects in a relational database.
• They are composed of rows and columns, where each row is a record and each column is an attribute of the data.
• Records (Rows):
• Records are individual entries in a table.
• Each record consists of values for the attributes defined by the columns.
• Fields (Columns):
• Fields are the individual pieces of data stored in a table.
• Each field has a specific data type, such as integer, varchar, date, etc.
• Keys:
• Keys are essential for identifying records uniquely and establishing relationships between tables.
• Primary Key: A column (or a combination of columns) that uniquely identifies each row in a table.
• Foreign Key: A column that creates a link between two tables. It corresponds to the primary key of another table, establishing a relationship between the two tables.
• Relationship:
• Relationships define how data in different tables relate to each other. Common types of relationships include.
• One-to-One: A single row in one table is associated with a single row in another table.
• One-to-Many: A single row in one table is associated with multiple rows in another table.
• Many-to-Many: Multiple rows in one table are associated with multiple rows in another table, usually managed through a junction table.
• Structured Query Language(SQL):
• SQL is the standard language for interacting with relational databases.
• It includes commands for querying data (SELECT), modifying data (INSERT, UPDATE, DELETE), and defining data structures (CREATE, ALTER, DROP).
• Store Procedure and Functions:
• Stored procedures and functions are precompiled SQL code that can be executed to perform specific tasks.
• They help in encapsulating complex logic and improving performance.
• Benefits of Database Approach:
• The database approach offers several benefits compared to traditional file-based systems.
• These benefits contribute to more efficient, reliable, and scalable data management. Here are the key advantages.
• Data Redundancy Control:
• Minimized Data Duplication: Centralized data storage reduces redundancy by eliminating duplicate data across different files and applications.
• Consistency: Ensures that each piece of data has a single, authoritative version, reducing inconsistencies and anomalies.
• Data Integrity and Accuracy:
• Data Validation: Enforces rules and constraints to ensure data accuracy and integrity.
• Standardization: Consistent data formats and validation checks across the database ensure high data quality.
• Improved Data Security:
• Access Control: User authentication and authorization mechanisms restrict access to sensitive data.
• Encryption: Data can be encrypted to protect it from unauthorized access and breaches.
• Enhanced Data Sharing:
• Concurrent Access: Multiple users and applications can access and manipulate data simultaneously without interference.
• Data Centralization: A centralized repository allows for efficient data sharing and collaboration among users.
• Efficient Data Retrieval and Manipulation:
• Query Optimization: Sophisticated query languages like SQL allow for efficient data retrieval and manipulation.
• Indexes: Use of indexes significantly speeds up data search and retrieval operations.
• Data Independence:
• Logical Data Independence: The ability to change the logical schema without altering the physical schema, allowing for flexibility in how data is stored and retrieved.
• Physical Data Independence Changes to the physical storage of data do not affect the logical schema.
• Improved Data Management:
• Data Models: Use of data models to represent complex data relationships in a structured way.
• Metadata Management: Metadata provides information about the data, making it easier to manage and utilize.
• Backup and Recovery:
• Data Recovery: Automated backup and recovery processes ensure data can be restored in case of failure or loss.
• Transaction Management: ACID properties (Atomicity, Consistency, Isolation, Durability) ensure reliable and consistent transaction processing.
• Support for Advanced Data Processing:
• Complex Queries: Support for complex queries and analytics, enabling sophisticated data processing and reporting.
• Data Mining and BI: Integration with data mining and business intelligence tools for in-depth data analysis and decision-making