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RDBMS Articles
Page 5 of 8
One-to-Many Relationship Model
In a "class roster" database, a teacher may teach zero or more classes, while a class is taught by one (and only one) teacher. In a "company" database, a manager manages zero or more employees, while an employee is managed by one (and only one) manager. In a "product sales" database, a customer may place many orders, while an order is placed by one particular customer. This kind of relationship is known as one-to-many. Why One-to-Many Cannot Be Represented in a Single Table If we begin with a table called Teachers and try to store classes taught, we ...
Read MoreEarly Database Models
A database model determines the logical structure of a database and defines how data can be stored, organized, and manipulated. Before databases were developed, the only way to store data was in file storage systems, which increased complexity as programmers had to perform complex parsing and relating operations to extract data. File Storage Complex, redundant Database Models Structured, ...
Read MoreCloud Databases
A cloud database is a database that has been optimized or built for a virtualized environment, deployed in a hybrid cloud, public cloud, or private cloud. Cloud databases offer the ability to pay for storage capacity and bandwidth on a per-user basis, provide scalability on demand, and deliver high availability. They also give enterprises the opportunity to support business applications in a software-as-a-service (SaaS) deployment. Cloud Database DB DB DB ...
Read MoreOperational Database
An operational database is a system designed to store information related to the day-to-day operations of an enterprise. Functional lines like marketing, employee relations, customer service, inventory management, and sales require such databases to maintain current and frequently accessed data. Operational databases are also known as OLTP (Online Transaction Processing) systems because they handle real-time transactions and support the ongoing operations of a business. Key Characteristics Real-time processing − Handle immediate transaction processing. High concurrency − Support multiple users accessing data simultaneously. Data integrity − Maintain ACID properties for reliable transactions. Normalized structure − Reduce data ...
Read MoreNoSQL Databases
NoSQL databases (Not Only SQL) are designed for large sets of distributed data. Some big data performance issues that are not effectively handled by relational databases are easily managed by NoSQL databases. They are very efficient at analyzing large-size unstructured data that may be stored across multiple virtual servers in the cloud. Types of NoSQL Databases NoSQL databases are categorized into four main types based on their data model − Document Store JSON-like documents MongoDB ...
Read MoreCommercial Database
A Commercial Database is a paid database service designed for users who need access to large volumes of specialized information. These databases are subject-specific, containing vast amounts of curated data that individual organizations cannot afford to collect and maintain on their own. Access is provided through commercial links or subscription plans. Commercial Database Access Model Commercial Database Paid Access ...
Read MoreEnd User Database
An End User Database is a shared database specifically designed for end users who are not concerned with the underlying transactions, operations, or technical details. The end user interacts only with the final product − a software application or interface − and the database presents summarized, meaningful information for their use. Raw Operational Database SQL, Transactions, CRUD Data Processing & Aggregation End User Database Interface Dashboards, Reports, Simple Views ...
Read MorePersonal database
A Personal Database is a small, single-user database that is stored and managed on a personal computer. The data is collected and used by an individual or a small group of people, typically within the same department of an organization. Personal databases are designed for simplicity and ease of use, making them ideal for managing personal information, small projects, or departmental data without the complexity of enterprise-level systems. Characteristics Personal databases have several key characteristics that distinguish them from larger database systems − Single-user − Designed for one user or a small group at a time. Small size − ...
Read MoreEntity Relationship Participation in Database
In a relationship, the Participation Constraint specifies the existence of an entity when it is related to another entity. It is also called the minimum cardinality constraint and specifies the number of instances of an entity that can participate in a relationship type. There are two types − Total Participation and Partial Participation. Total Participation In total participation, each entity in the entity set must be involved in at least one relationship instance. No entity can exist without participating in the relationship. This is also known as mandatory participation. Example − Consider two entities Employee and Department related via the ...
Read MoreMultiple Relation Queries and JOIN Ordering
Multiple relation queries involve joining several tables to produce a result set. The order in which JOIN operations are executed can significantly affect query performance. Query optimization determines the most efficient execution plan by evaluating different JOIN orderings. Challenges The query optimizer must determine the most efficient execution plan considering join selectivity, data size, distribution, and available access paths. With n tables, there are n! possible join orderings, making optimal selection a complex process. Table A 1M rows Table B ...
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