https://wikimd.com/index.php?action=history&feed=atom&title=Relational_databaseRelational database - Revision history2026-04-23T11:25:38ZRevision history for this page on the wikiMediaWiki 1.44.2https://wikimd.com/index.php?title=Relational_database&diff=5652314&oldid=prevPrab: CSV import2024-04-24T01:28:57Z<p>CSV import</p>
<p><b>New page</b></p><div>[[Image:Relational_database_terms.svg|Relational database terms|thumb]] '''Relational database''' is a type of [[database]] that stores and provides access to data points that are related to one another. Relational databases are based on the relational model, an intuitive, straightforward way of representing data in [[tables]]. In a relational database, each row in the table is a record with a unique ID called the [[primary key]], and each column is an attribute of the data.<br />
<br />
==Overview==<br />
The concept of relational databases was first proposed by [[Edgar F. Codd]] at [[IBM]] in 1970, in his seminal paper "A Relational Model of Data for Large Shared Data Banks." The relational model's foundation is the mathematical concept of a relation, derived from set theory and predicate logic. This model organizes data into one or more tables (or "relations") of columns and rows, with a unique key identifying each row. Rows in a table can be linked to rows in other tables by adding a column for the unique key of the linked row, known as a [[foreign key]].<br />
<br />
==Features==<br />
Relational databases have several key features:<br />
* '''Structured Query Language (SQL)''': A standard user and application program interface used in querying, updating, and managing relational databases.<br />
* '''Data Integrity''': Ensures accuracy and consistency of data over its lifecycle. This is often enforced through constraints, such as primary keys and foreign keys.<br />
* '''Normalization''': A process that organizes data to reduce redundancy and improve data integrity.<br />
* '''Transactions''': Sequences of operations performed as a single logical unit of work, allowing for data consistency. Transactions are managed according to the ACID properties (Atomicity, Consistency, Isolation, Durability).<br />
* '''Security''': Mechanisms to control access to data, including authentication and authorization.<br />
<br />
==Advantages==<br />
Relational databases offer several advantages:<br />
* '''Flexibility for querying data''': Users can query the database without knowing the data's structure beforehand.<br />
* '''Ease of use''': The tabular representation of data makes relational databases easy to understand and use.<br />
* '''Data integrity and accuracy''': The database ensures that all data is accurate and consistent through constraints and transactions.<br />
* '''Scalability and performance''': Modern relational databases are designed to scale to meet the needs of large data volumes and high transaction rates.<br />
<br />
==Disadvantages==<br />
Despite their advantages, relational databases also have some limitations:<br />
* '''Complexity''': Designing and maintaining a relational database can be complex, especially as the size and complexity of the database grow.<br />
* '''Performance issues''': For very large volumes of data or highly complex queries, relational databases may not perform as well as other types of databases, such as [[NoSQL databases]].<br />
* '''Rigid schema''': Changes to the database schema require significant effort and can be difficult to implement in a live database.<br />
<br />
==Examples of Relational Database Management Systems (RDBMS)==<br />
Several popular relational database management systems (RDBMS) include:<br />
* [[Oracle Database]]<br />
* [[Microsoft SQL Server]]<br />
* [[MySQL]]<br />
* [[PostgreSQL]]<br />
* [[IBM DB2]]<br />
<br />
Relational databases play a critical role in almost all areas where data is stored and managed, from financial services to healthcare, demonstrating their versatility and reliability.<br />
<br />
[[Category:Databases]]<br />
[[Category:Data management]]<br />
{{stb}}</div>Prab