Sure, let's dive into the key concepts and principles of a Relational Database Management System (RDBMS):
Relational Model: The foundation of an RDBMS is based on the relational model, which organizes data into tables (relations) consisting of rows (tuples) and columns (attributes). Each table represents an entity, and each row represents a unique record of that entity.
Tables: Tables are structured with predefined columns that define the attributes or properties of the entities they represent. For example, a "Customers" table might have columns like CustomerID, Name, Address, etc.
Rows: Each row in a table represents a specific instance of the entity being modeled. For instance, in a "Customers" table, each row would represent a unique customer.
Columns: Columns define the type of data that can be stored in them (such as integers, strings, dates, etc.) and enforce constraints (like uniqueness or not null) to maintain data integrity.
Keys: Keys are used to uniquely identify rows within a table. The Primary Key uniquely identifies each record in the table, while a Foreign Key establishes a link between tables, ensuring referential integrity.
Relationships: Relationships between tables are established using keys. A common relationship is the One-to-Many relationship, where one record in one table can relate to many records in another table.
Normalization: This process eliminates redundancy and ensures data integrity by organizing data into tables and defining relationships between them. It reduces data duplication and improves efficiency.
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ACID Properties: Transactions in RDBMS systems are designed to be reliable and consistent, adhering to the ACID properties:
- Atomicity: Transactions are treated as a single unit of work.
- Consistency: Data must meet all defined rules (constraints) before being committed.
- Isolation: Transactions occur independently without interference.
- Durability: Changes made by committed transactions are permanent and survive system failures.
SQL (Structured Query Language): SQL is the standard language used to interact with RDBMS. It provides commands for querying data, updating records, defining schemas, and managing permissions.
Transactions: A transaction is a sequence of SQL operations that are treated as a single unit. Transactions ensure data consistency and integrity by either committing (making changes permanent) or rolling back (reverting changes) based on success or failure.
These concepts form the backbone of RDBMS systems, providing a robust framework for storing, manipulating, and retrieving data in a structured manner.
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