The Relational Database Model, developed by Edgar F. Codd in the 1970s, is a cornerstone of modern database management systems (DBMS). It's based on mathematical set theory and predicate logic and has become the predominant model for organizing and managing data in various applications. Here are the key characteristics of the relational database model:
1. Tabular Structure: Data is organized into tables, also known as relations. Each table consists of rows (tuples) and columns (attributes). Rows represent individual records, while columns represent attributes or properties of those records.
2. Primary Keys: Each table typically has a primary key, which uniquely identifies each row within the table. This ensures that each record in the table is unique and identifiable.
3. Foreign Keys: Relationships between tables are established using foreign keys. A foreign key in one table refers to the primary key of another table, creating a link between the two tables. This allows for the representation of complex relationships between entities.
4. Normalization: Relational databases follow the principles of normalization to reduce redundancy and improve data integrity. Normalization involves organizing data into multiple tables and eliminating redundant information.
5. ACID Properties: Relational databases typically adhere to the ACID (Atomicity, Consistency, Isolation, Durability) properties, which ensure data consistency and reliability. Transactions are atomic, meaning they are either completed in full or not at all, and changes to the database are consistent and durable.
6. SQL (Structured Query Language): SQL is the standard language used to interact with relational databases. It provides a powerful and flexible means of querying, updating, and managing data stored in relational databases.
7. Data Integrity Constraints: Relational databases support various integrity constraints to maintain the quality and consistency of data. These constraints include entity integrity, referential integrity, domain integrity, and user-defined integrity rules.
8. Data Independence: Relational databases provide a level of abstraction between the physical storage of data and the logical structure of the database, allowing for data independence. Changes to the underlying storage structure do not affect the way data is accessed or manipulated.
9. Scalability: Relational databases are scalable and can handle a wide range of applications, from small-scale single-user systems to large-scale enterprise applications with millions of records and concurrent users.
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