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With the help of following MySQL query, we can see the list of MySQL database −mysql> SELECT schema_name FROM information_schema.schemata; +--------------------+ | schema_name | +--------------------+ | information_schema | | gaurav | | mysql | | performance_schema | | query | | query1 | | sys | | tutorials | +--------------------+ 8 rows in set (0.00 sec)We can also use WHERE clause with this query as follows −mysql> SELECT schema_name FROM information_schema.schemata WHERE schema_name LIKE '%schema' OR schema_name LIKE '%s'; +--------------------+ | schema_name | +--------------------+ | information_schema | | performance_schema | | sys | | tutorials | +--------------------+ 4 rows in set (0.00 sec)
There may be something wrong which can happen to the database server e.g., the server was shutdown unexpectedly, error while writing data to the hard disk, etc. These situations could make the database operate incorrectly and in the worst case, it can be crashed.With the help of CHECK TABLE statement MySQL allows us to check the integrity of database tables. Its syntax would be as follows −CHECK TABLE table_nameHere, table_name is the name of the table.ExampleWe are running this statement for the table Student_info as follows −mysql> CHECK table student_info\G *************************** 1. row *************************** Table: query.student_info ... Read More
Ref ParameterA reference parameter is a reference to a memory location of a variable. When you pass parameters by reference, unlike value parameters, a new storage location is not created for these parameters.You can declare the reference parameters using the ref keyword. The following is an example −Example Live Demousing System; namespace CalculatorApplication { class NumberManipulator { public void swap(ref int x, ref int y) { int temp; temp = x; /* save the value of x */ x = y; /* put ... Read More
A member function i.e. method of a class is a function that has its definition or its prototype within the class definition similar to any other variable. It operates on any object of the class of which it is a member, and has access to all the members of a class for that object.The following is an example −public void setLength( double len ) { length = len; } public void setBreadth( double bre ) { breadth = bre; }The following is an example showing how to access class member functions in C# −Example Live Demousing System; ... Read More
MySQL query optimizer is an important element of the MySQL server that makes an best question execution set up for a query. For a particular query, the query optimizer uses the stored key distribution and other factors to decide the order in which tables should be joined when you performing the join, and which index should be used for a specific table.However, the key distributions can be sometimes inaccurate e.g., after you have done a lot of data changes in the table including insert, delete, or update. IIf the key distribution isn't correct, the question optimizer could pick a nasty ... Read More
While working with the database, we have a tendency to do plenty of changes like insert, update and delete data within the table which will cause the physical storage of the table fragment. As a result, the performance of database server is degraded.MySQL provides us with OPTIMIZE TABLE statement that allows you to optimize the table to avoid this defragmenting problem. Its syntax would be as follows −OPTIMIZE TABLE table_nameHere, table_name is the name of the table.ExampleWe are running this statement for the table Student_info as follows −mysql> Optimize table student_info\G *************************** 1. row *************************** Table: query.student_info Op: ... Read More
Let us see an example to find the number of dimensions of an array, using the Rank property.arr.RankHere, arr is our array −int[, ] arr = new int[5, 5];If you want to get the rows and columns the array has, then use the GetLength property −arr.GetLength(0); arr.GetLength(1);The following is the complete code −Example Live Demousing System; class Program { static void Main() { int[, ] arr = new int[4, 5]; Console.WriteLine(arr.GetLength(0)); Console.WriteLine(arr.GetLength(1)); Console.WriteLine("Upper Bound: {0}", arr.GetUpperBound(0).ToString()); Console.WriteLine("Lower Bound: {0}", arr.GetLowerBound(0).ToString()); ... Read More
The @prefix states hat you don't need to escape special characters in the string following to the symbol.The following statement@"D:ew"is equal to:"D:ew"The @ prefix is also used if you want to have large strings and want it to be displayed across multiple lines. The following is an example showing multi-line string −Example Live Demousing System; namespace Demo { class Program { static void Main(string[] args) { string str = @"Welcome User, Kindly wait for the image to load"; Console.WriteLine(str); } } }OutputWelcome User, Kindly wait for the image to load
The RemoveAt method in C# is used to remove an element in a list at a position you set.Firstly, set elements in the list −var subjects = new List(); subjects.Add("Physics"); subjects.Add("Chemistry"); subjects.Add("Biology"); subjects.Add("Science");To remove an element, set the index from where you want to eliminate the element. The following is to remove element from the 3rd position −subjects.RemoveAt(2);Let us see the complete code −Example Live Demousing System; using System.Collections.Generic; public class Demo { public static void Main(string[] args){ var subjects = new List(); subjects.Add("Physics"); subjects.Add("Chemistry"); subjects.Add("Biology"); ... Read More
A class constructor is a special member function of a class that is executed whenever we create new objects of that class. A default constructor does not have any parameter.The following is an example showing how to work with default constructor in C# −Example Live Demousing System; namespace LineApplication { class Line { private double length; // Length of a line public Line(double len) { //Parameterized constructor Console.WriteLine("Object is being created, length = {0}", len); length = len; } ... Read More