Found 6842 Articles for Database

A database that is dispersed among several computers or locations, each of which contains a subset of the data, is known as a distributed database. No matter where the data is kept, a distributed database management system (DDBMS) administers the distributed database and gives users access to it. The ideas of distributed databases, including their benefits, drawbacks, and many forms, will be covered in this article. Types of Distributed Databases Homogeneous Distributed Databases − All of the locations in a homogeneous distributed database make use of the same DBMS and operating systems. Examples -Oracle Real Application Clusters (RAC), ... Read More

In the form of a relation, a database is used to mimic the status of some part of the real world outside. Database systems, in general, store just one state, which is the present state of the actual world, and do not keep data regarding prior and past states, except sometimes as audit trails. If the real world's current state changes, the database is edited and updated, and knowledge about the previous state is lost. But, in the majority of real-world applications, it is important to store and retrieve information about previous states. A student database, for example, must have ... Read More

Indexing in Apache Cassandra is a way to improve the efficiency and performance of queries on non-primary key columns. In Cassandra, data is organized in tables and each table has a primary key, which consists of one or more columns that uniquely identify each row in the table. Queries that use the primary key to retrieve data are very efficient, but queries that use other columns in the WHERE clause can be slower. Cassandra has secondary indexes that enable querying on columns other than the main key columns to solve this problem. A secondary index is built on a table's ... Read More

This article will provide a broad review of computer-based controls before moving into the computer-based controls in databases available in a multi-user database system. Let's discuss all of them one by one. A group of security procedures called computer-based controls are used in DBMSs to safeguard the database against illegal access, alteration, or destruction. These safeguards are intended to guarantee that the database can only be accessed by authorized users and that the data is safe from accidental or deliberate destruction. Physical controls and administrative processes are only a couple of the several remedies available to deal with threats to ... Read More

SAN stands for "Storage Area Network" in its complete form. Block-level data storage is offered via a Storage Area Network (SAN), a dedicated, autonomous, and ultra-speed network that gives different servers access to a common pool of storage devices. Data transmission between the server and storage device as well as data transfer between storage systems are the two major goals of storage area networks. Storage area networks are mostly used to access storage devices from servers, such as tape libraries and disk-based devices. Servers, network infrastructure, and storage make up the three main parts of a storage area network. Nevertheless, ... Read More

Star schema design is a type of database schema used in data warehousing that is designed to make querying and analyzing large datasets more efficient. The schema consists of a central fact table that contains the data to be analyzed and one or more dimension tables that provide additional information about the data in the fact table. Components of Star Schema A star schema is made up of four major components. These are as follows − Fact Table Dimension Table Attributes Attribute Hierarchies Let us go over them one by one − Facts These are monetary ... Read More

Complex type structures for objects and literals are also crucial in the context of database management systems (DBMS). In this context, difficult types refer to data types that can store multiple values within a single column or attribute. This allows for more efficient and organized storage of complex data, such as arrays or nested objects, in a database. When it comes to databases, complex type structures for objects and literals can be incredibly useful for storing and retrieving data efficiently. In this article, we will explore how complex type structures can be implemented in databases, their advantages, and some of ... Read More

Introduction Big Data has become a buzzword in the technology industry over the past decade. With vast amounts of data being generated every second, it's essential to manage and process it efficiently. That’s where Hadoop and Spark come into play. Both are powerful big data processing frameworks that can handle large datasets at scale. Hadoop Overview History and Development Hadoop was created by Doug Cutting and Mike Cafarella in 2005 while they were working at Yahoo. The project was named after a toy elephant that belonged to Cutting's son. Initially designed to handle large amounts of unstructured data, Hadoop has ... Read More

Data Definition Language(DDL) is used for describing data and its relationship in a database. It is also used to define the database schema. The commands only affect the database structure and not the data. The main DDL commands are create, alter, drop and truncate. Create Statement It is used to create a database or table. While creating the table, we specify table_name, column_name followed by data_types(int, float, varchar, etc) and constraints(primary key, not null, etc) Syntax CREATE TABLE table_name ( column1 datatype, column2 datatype, ..... ) Example In this ... Read More

DCL(Data Control Language) work is to deal with sql commands that are used to permit a user to access, modify and work on a database. it is used to access stored data. It gives access, revoke access and change the permission to the owner of the database as per the requirement. It helps in how sql can use a user authority to modify or retrieve data and protect against unauthorised access. It complements data manipulation language(DML) and data definition language(DDL). It is the simplest among the three command It is basically used for enforcing data security. DCL Commands ... Read More