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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to disable MySQL foreign key checks and what are the benefits ofndisabling it?
We can disable foreign key checks with the help of the following statement −mysql> Set foreign_key_checks = 0; Query OK, 0 rows affected (0.00 sec)And we can enable it with the help of the following statement −mysql> Set foreign_key_checks = 1; Query OK, 0 rows affected (0.00 sec)Some benefits of disabling foreign key checks are as follows −After disabling foreign key checks we can load data into parent and child table in any order. Otherwise, we must have to load the data first in the parent table and then in the child table.Without disabling foreign key checks we cannot drop ...
Read MoreDatabase operations in Java
This article provides an example of how to create a simple JDBC application. This will show you how to open a database connection, execute a SQL query, and display the results.Creating JDBC ApplicationThere are following six steps involved in building a JDBC application −Import the packages: Requires that you include the packages containing the JDBC classes needed for database programming. Most often, using import java.sql.* will suffice.Register the JDBC driver: Requires that you initialize a driver so you can open a communication channel with the database.Open a connection: Requires using the DriverManager.getConnection() method to create a Connection object, which represents ...
Read MoreWhat are the different ways to maintain data integrity in child table when the record is deleted in parent table?
When two tables are connected with Foreign key and data in the parent table is deleted, for which record exists in child table too, then followings are the ways to maintain data integrity −On Delete CascadeThis option will remove the record from child table too if that value of the foreign key is deleted from the main table.On Delete Null This option will set all the values in that record of child table as NULL, for which the value of the foreign key is deleted from the main table.
Read MoreCounting number of paragraphs in text file using java
We can read paragraphs in a file by reading it in a string and then spilting based on "\r" pattern. See the example below −ExampleConsider the following text file in the classpath.test.txtThis is Line 1 This is Line 2 This is Line 3 This is Line 4 This is Line 5 This is Line 6 This is Line 7 This is Line 8 This is Line 9 This is Line 10Tester.javaimport java.io.File; import java.io.FileInputStream; import java.io.IOException; public class Tester { public static void main(String args[]) throws IOException { FileUtil fileUtil = ...
Read MoreCounting number of characters in text file using java
We can read characters in a file using BufferedReader class of Java. See the example below −ExampleConsider the following text file in the classpath.test.txtThis is Line 1 This is Line 2 This is Line 3 This is Line 4 This is Line 5 This is Line 6 This is Line 7 This is Line 8 This is Line 9 This is Line 10Tester.javaimport java.io.BufferedReader; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.IOException; import java.io.InputStreamReader; public class Tester { private static final String FILE_PATH = "data.txt"; public static void main(String args[]) throws IOException { ...
Read MoreUsing Operators in Analytic Privilege in SAP HANA
You have the following Operators that can be used to define restrictions
Read MoreLimitations of Database Management System
Database Management System is quite useful compared to the file based management system. However, it does have some disadvantages. Some of those are as follows −More CostlyCreating and managing a database is quite costly. High cost software and hardware is required for the database. Also highly trained staff is required to handle the database and it also needs continuous maintenance. All of these ends up making a database quite a costly venture.High ComplexityA Database Management System is quite complex as it involves creating, modifying and editing a database. Consequently, the people who handle a database or work with it need ...
Read MoreFile-based Data Management System
The systems that are used to organize and maintain data files are known as file based data systems. These file systems are used to handle a single or multiple files and are not very efficient. FunctionalitiesThe functionalities of a File-based Data Management System are as follows −A file based system helps in basic data management for any user.The data stored in the file based system should remain consistent. Any transactions done in the file based system should not alter the consistency property. The file based system should not allow any illegal or potentially hazardous operations to occur on the data.The file based ...
Read MoreWhy do we need a Database
A database is a collection of data, usually stored in electronic form. A database is typically designed so that it is easy to store and access information.A good database is crucial to any company or organisation. This is because the database stores all the pertinent details about the company such as employee records, transactional records, salary details etc.The various reasons a database is important are −Manages large amounts of dataA database stores and manages a large amount of data on a daily basis. This would not be possible using any other tool such as a spreadsheet as they would simply ...
Read MoreObject-oriented Data Model
Object oriented data model is based upon real world situations. These situations are represented as objects, with different attributes. All these object have multiple relationships between them.Elements of Object oriented data modelObjectsThe real world entities and situations are represented as objects in the Object oriented database model.Attributes and MethodEvery object has certain characteristics. These are represented using Attributes. The behaviour of the objects is represented using Methods.ClassSimilar attributes and methods are grouped together using a class. An object can be called as an instance of the class.InheritanceA new class can be derived from the original class. The derived class contains ...
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