Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Introduction A referential integrity constraint ensures that a foreign key value in one table matches a primary key value in another table. This helps to maintain the consistency and accuracy of the data in a database by preventing the insertion of incorrect or invalid data. However, if there is an update anomaly, the referential integrity constraint can be violated, which can lead to inconsistencies in the data. An update anomaly occurs when an update to a primary key value in a table causes multiple foreign key values in other tables to become incorrect. To demonstrate an update anomaly in referential ... Read More
Introduction A SQL query is a request for data from a database. In the context of demonstrating a deletion anomaly in a table with referential integrity, a SQL query would be used to delete a record from the parent table and observe the impact on the related records in the child table. To demonstrate a deletion anomaly, we can create two tables with a foreign key constraint, insert some sample data, and then use a `DELETE` statement to delete a record from the parent table. We can then use a `SELECT` statement to retrieve the data from the child table ... Read More
Introduction To demonstrate an addition anomaly in a referential integrity in a table, we can create a simple database with two tables: a parent table and a child table. The parent table should have a primary key column, and the child table should have a foreign key column that references the primary key column in the parent table. We can then insert some rows into both tables and run a SELECT statement on the child table that filters the results based on a column from the parent table. If we delete a row from the parent table, the result of ... Read More
Bash history is a powerful tool that can help you keep track of all the commands you've executed in your terminal. It can be especially useful when you're working with multiple terminal windows, as it allows you to easily switch between them and pick up where you left off. In this article, we'll show you how to preserve bash history in multiple terminal windows on Linux, and explain why it's so important. Why Preserve Bash History? Preserving bash history is important because it allows users to easily recall commands they have previously executed in the terminal. This can save time ... Read More
One of the most powerful features of the Linux operating system is the ability to find and manipulate files quickly and easily from the command line. This can be especially useful when working with large numbers of files or when you need to automate certain tasks. In this article, we will take a look at two of the most commonly used command-line tools for finding and compressing files on Linux: the find command and the tar command. Finding Files with the find Command The find command is a powerful tool that allows you to search for files on your Linux ... Read More
The netcat command in Linux is a powerful tool for network communication and troubleshooting. It allows users to read and write data to network connections using the TCP or UDP protocols. In this article, we will explore the various uses and capabilities of the netcat command, including examples of how to use it for network communication and troubleshooting. What is the netcat command? The netcat command, also known as nc, is a command-line utility that allows users to read and write data over a network connection. It can be used to establish connections to servers and clients, send and receive ... Read More
There are several ways to remove the first line of a text file in Linux. In this article, we will go over three different methods that can be used to accomplish this task. Method 1: Using the head Command The head command is a Linux utility that is used to display the first few lines of a text file. It can also be used to remove the first line of a text file by using the -n option. The -n option is used to specify the number of lines that should be displayed. By specifying -1, we can remove the ... Read More
Linux is a powerful operating system that allows users to perform a wide range of tasks, including redirecting the output of an already running process. This feature is particularly useful when you want to send the output of a process to a file, a different terminal window, or even a remote server. In this article, we will discuss how to redirect the output of an already running process on Linux, with examples and sub-headings. Using gdb to Redirect the Output Another method to redirect the output of an already running process on Linux is by using the GNU Debugger (gdb) ... Read More
Introduction In SQL, a database can be set to single user mode or multi user mode. When a database is in single user mode, only one user can connect to the database at a time. This can be useful for maintenance tasks that need to be performed on the database, as it ensures that no other users are modifying the data while the maintenance is being done. However, once the maintenance is complete, it is usually necessary to set the database back to multi user mode so that multiple users can connect to the database and access the data. This ... Read More
Introduction In an Oracle Database, privileges are used to control access to the database's objects and operations. A privilege is a permission to perform a specific action on a specific object, such as SELECTing data from a table or EXECUTing a stored procedure. When you create a user in the database, that user does not have any privileges by default. In order for the user to be able to perform any actions, you must grant them the necessary privileges. This can be done by using the GRANT command in SQL command line. When a user has been granted a privilege, ... Read More