Article Categories
- All Categories
-
Data Structure
-
Networking
-
RDBMS
-
Operating System
-
Java
-
MS Excel
-
iOS
-
HTML
-
CSS
-
Android
-
Python
-
C Programming
-
C++
-
C#
-
MongoDB
-
MySQL
-
Javascript
-
PHP
-
Economics & Finance
Articles on Trending Technologies
Technical articles with clear explanations and examples
Commercial 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 ...
Read MoreMultiversion Concurrency Control Techniques
This article has a truncated Drawbacks section at the end. Let me fix that and clean up the SVGs: It is essential to maintain data consistency and prevent concurrency issues in database systems when multiple transactions access the same data simultaneously. Multiversion Concurrency Control (MVCC) techniques provide an efficient way to achieve this by maintaining multiple versions of data items. Concurrency Control Protocols Database systems provide concurrency control to ensure isolation among transactions, maintain consistency, and resolve conflicts arising from read−write and write−read operations. The main techniques used are − Two−phase locking protocol Timestamp ordering ...
Read MoreCount odd and even digits in a number in PL/SQL
We are given a positive integer of digits and the task is to calculate the count of odd and even digits in a number using PL/SQL. PL/SQL is a combination of SQL along with the procedural features of programming languages. It was developed by Oracle Corporation in the early 90's to enhance the capabilities of SQL. PL/SQL is one of three key programming languages embedded in the Oracle Database, along with SQL itself and Java. Input int number = 23146579 Output count of odd digits in a number are : 5 count of even digits in a number are : ...
Read MoreDifference between Primary key and Foreign key in Database
In a relational database, keys are the most important elements to maintain the relationship between two tables or to uniquely identify the data from a table. Primary key is used to identify data uniquely therefore two rows can't have the same primary key. It can't be null. On the other hand, foreign key is used to maintain relationship between two tables. The primary key of a table acts as the foreign key in another table. The Foreign key in a table helps enforce Referential Integrity constraint. Read this tutorial to find out more about Primary and Foreign keys and ...
Read MoreDifference between Function and Procedure
SQL (Structured Query Language) is a computer language which is used to interact with an RDBMS (Relational Database Management System). It is basically a method of managing, organizing, and retrieving data from a relational database. In SQL, two important concepts are used namely, function and procedure. A function calculates the results of a program based on the inputs provided, whereas a procedure is used to perform some tasks in a specific order. There are many other differences between functions and procedures, which we will discuss in this article. What is Function? A function, in the context of ...
Read MoreVarious Types of Keys in DBMS
The different types of keys in DBMS are − Candidate Key − The candidate keys in a table are defined as the set of keys that is minimal and can uniquely identify any data row in the table. Primary Key − The primary key is selected from one of the candidate keys and becomes the identifying key of a table. It can uniquely identify any data row of the table. ...
Read More