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In a distributed database management system, the database is not stored at a single location. Rather, it may be stored in multiple computers at the same place or geographically spread far away. Despite all this, the distributed database appears as a single database to the user. A diagram to better explain this is as follows:As seen in the figure, the components of the distributed database can be in multiple locations such as India, Canada, Australia, etc. However, this is transparent to the user i.e the database appears as a single entity.Types of Distributed Database Management SystemThe following are the types ... Read More
Locks are an integral part to maintain concurrency control in DBMS. A transaction in any system implementing lock based concurrency control cannot read or write a statement until it has obtained the required locks.There are two types of locks in Lock based protocols. These are:Binary Locks - These can only be in one of two states, locked or unlocked.Shared/Exclusive Locks - Shared locks are acquired when only read operation is to be performed. Shared locks can be shared between multiple transactions as there is no data being altered. Exclusive locks are used when write operation is performed. Only the transaction holding the ... Read More
While exporting the data from MySQL table to a text file we can use ‘FIELDS TERMINATED BY’, ‘ENCLOSED BY’, ‘LINES TERMINATED BY’ and other options too to put the values of fields in different settings of the text file. It can be illustrated with the help of the following example −ExampleSuppose we are having following data from table ‘Student_info’ −mysql> Select * from Student_info; +------+---------+------------+------------+ | id | Name | Address | Subject | +------+---------+------------+------------+ | 101 | YashPal | Amritsar | History | | 105 | Gaurav | Chandigarh | Literature | | ... Read More
In C#, a structure is a value type data type. It helps you to make a single variable hold related data of various data types. The struct keyword is used for creating a structure.When you define a class, you define a blueprint for a data type.The following are the differences between classes and structures in C# −Classes are reference types and structs are value typesUnlike classes, structures cannot inherit other structures or classes.Structures cannot be used as a base for other structures or classes.When you create a struct object using the New operator, it gets created and the appropriate constructor ... Read More
It can be done by providing the column(s) names in the SELECT … INTO OUTFILE statement while exporting the data from MySQL table into a file. We are illustrating it with the help of the following example −ExampleSuppose we are having following data from table ‘Student_info’ −mysql> Select * from Student_info; +------+---------+------------+------------+ | id | Name | Address | Subject | +------+---------+------------+------------+ | 101 | YashPal | Amritsar | History | | 105 | Gaurav | Chandigarh | Literature | | 125 | Raman | Shimla | Computers | | 130 ... Read More
Suppose if we have a line prefix in the text file then with the help of using ‘LINES STARTING BY’ option we can ignore that prefix and import correct data into MySQL table. It can be understood with the help of the following example −ExampleSuppose we are using ‘VALUE’ as the ‘LINE PREFIX’ in the text file as follows −id, Name, Country, Salary VALUE:105, Chum*, Marsh, USA, 11000 106, Danny*, Harrison, AUS, 12000Now while importing this text file into MySQL table then we ... Read More
Sometimes the input text files have the text fields enclosed by double quotes and to import data from such kind of files we need to use the ‘ENCLOSED BY’ option with LOAD DATA INFILE statement. We are considering the following example to make it understand −ExampleFollowings are the comma-separated values in A.txt file −100, ”Ram”, ”INDIA”, 25000 101, ”Mohan”, ”INDIA”, 28000We want to import this data into the following file named employee2_tbl −mysql> Create table employee2_tbl(Id Int, Name Varchar(20), Country Varchar(20), Salary Int); Query OK, 0 rows affected (0.1 sec)Now, the transfer of data from a file to a ... Read More
Transferring the information between MySQL and data files mean importing data from data files into our database or exporting data from our database into files. MySQL is having two statements that can be used to import or export data between MySQL and data files −LOAD DATA INFILEThis statement is used for importing the data from data files into our database. It reads data records directly from a file and inserts them into a table. Its syntax would be as follows −SyntaxLOAD DATA LOCAL INFILE '[path/][file_name]' INTO TABLE [table_name ];Here, the path is the address of the file.file_name is the name ... Read More
Comments are used for explaining the code. Compilers ignore the comment entries. The multiline comments in C# programs start with /* and terminate with the characters */ as shown below.Multi-line comments/* The following is a multi-line comment In C# /*The /*...*/ is ignored by the compiler and it is put to add comments in the program.Single line comments// variable int a = 10;The following is a sample C# program showing how to add single-line as well as multi-line comments −Example Live Demousing System; namespace HelloWorldApplication { class HelloWorld { static void Main(string[] args) { ... Read More
First, find the reverse of the string to check if a string is a palindrome or not −Array.reverse()Now use the equals() method to match the original string with the reversed. If the result is true, that would mean the string is Palindrome.Let us try the complete example. Here, our string is “Madam”, which is when reversed gives the same result −Example Live Demousing System; namespace Demo { class Program { static void Main(string[] args) { string string1, rev; string1 = "Madam"; char[] ch = string1.ToCharArray(); ... Read More