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Spatial data is associated with geographic locations such as cities, towns etc. A spatial database is optimized to store and query data representing objects. These are the objects which are defined in a geometric space.Characteristics of Spatial DatabaseA spatial database system has the following characteristicsIt is a database systemIt offers spatial data types (SDTs) in its data model and query language.It supports spatial data types in its implementation, providing at least spatial indexing and efficient algorithms for spatial join.ExampleA road map is a visualization of geographic information. A road map is a 2-dimensional object which contains points, lines, and polygons ... Read More
We have a sample string with spaces −str ="Hello World !";Use the Replace() method in C# to replace all spaces in a string with ‘%20’ −str2 = str.Replace(" ", "%20");ExampleYou can try to run the following code to replace all spaces in a string with ‘%20’.Live Demousing System; class Demo { static void Main() { String str, str2; str ="Hello World !"; Console.WriteLine("String: "+str); str2 = str.Replace(" ", "%20"); Console.WriteLine("String (After replacing): "+str2); } }OutputString: Hello World ! String (After replacing): Hello%20World%20!
Our sample string is −myStr = "Tom";To reverse the string, firstly find the length of the string −// find string length int len; len = myStr.Length - 1;Now, use a while loop until the length is greater than 0 −while (len >= 0) { rev = rev + myStr[len]; len--; }ExampleYou can try to run the following code to reverse a string in C#.Live Demousing System; class Demo { static void Main() { string myStr, rev; myStr = "Tom"; rev =""; Console.WriteLine("String is {0}", myStr); ... Read More
To return a value from a JavaScript function, use the return statement in JavaScript. You need to run the following code to learn how to return a value −Example function concatenate(name, age) { var val; val = name + age; return val; } function DisplayFunction() { var result; result = concatenate('John ', 20) ; document.write (result ); } Click the following button to call the function
It is quite possible to insert the NULL keyword as a value in a character type column having NOT NULL constraint because NULL is a value in itself. Following example will exhibit it −ExampleSuppose we have a table test2 having character type column ‘Name’ along with NOT NULL constraint on it. It can be checked from the DESCRIBE statement as follows −mysql> Describe test2\G *************************** 1. row *************************** Field: id Type: int(11) Null: NO Key: Default: NULL Extra: *************************** 2. row *************************** Field: NAME Type: varchar(20) Null: NO Key: ... Read More
Firstly, set the original array −int[] arr = { 15, 16, 17, 18 }; // Original Array Console.WriteLine("Original Array= "); foreach (int i in arr) { Console.WriteLine(i); }Now, use the Array.reverse() method to reverse the array −Array.Reverse(arr);ExampleThe following is the complete code to reverse an array in C#Live Demousing System; class Demo { static void Main() { int[] arr = { 15, 16, 17, 18 }; // Original Array Console.WriteLine("Original Array= "); foreach (int i in arr) { Console.WriteLine(i); } // Reverse Array Array.Reverse(arr); Console.WriteLine("Reversed Array= "); foreach (int j in arr) { Console.WriteLine(j); } Console.ReadLine(); } }OutputOriginal Array= 15 16 17 18 Reversed Array= 18 17 16 15
Let’s say the following is the string −Hello WorldAfter reversing the string, the words should be visible like −olleH dlroWExampleUse the reverse() method and try the following code to reverse words in a string.Live Demousing System; using System.Linq; class Demo { static void Main() { // original string string str = "Hello World"; // reverse the string string res = string.Join(" ", str.Split(' ').Select(s => new String(s.Reverse().ToArray()))); Console.WriteLine(res); } }OutputolleH dlroW
We can remove a NOT NULL constraint from a column of an existing table by using the ALTER TABLE statement.ExampleSuppose we have a table ‘test123’ having a NOT NULL constraint on column ‘ID’ as follows −mysql> DESCRIBE test123; +-------+---------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+---------+------+-----+---------+-------+ | ID | int(11) | NO | | NULL | | | Date | date | YES | | NULL | | +-------+---------+------+-----+---------+-------+ 2 rows in set (0.04 sec)Now if we ... Read More
Firstly find the hostname using the Dns.GetHostName() method in C# −String hostName = string.Empty; hostName = Dns.GetHostName(); Console.WriteLine("Hostname: "+hostName);Now, use the IPHostEntry.AddressList Property to get IP Address −IPHostEntry myIP = Dns.GetHostEntry(hostName); IPAddress[] address = myIP.AddressList;ExampleTry the following code to display IP address −using System; using System.Net; class Program { static void Main() { String hostName = string.Empty; hostName = Dns.GetHostName(); IPHostEntry myIP = Dns.GetHostEntry(hostName); IPAddress[] address = myIP.AddressList; for (int i = 0; i < address.Length; i++) { Console.WriteLine("IP Address {1} : ",address[i].ToString()); } Console.ReadLine(); } }
We can apply the NOT NULL constraint to a column of an existing MySQL table with the help of ALTER TABLE statement. SyntaxALTER TABLE table_name MODIFY colum_name datatype NOT NULL; Examplemysql> Create table test123(ID INT, Date DATE); Query OK, 0 rows affected (0.19 sec) mysql> Describe test123; +-------+---------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+---------+------+-----+---------+-------+ | ID | int(11) | YES | | NULL | | | Date | date | YES | | NULL | | +-------+---------+------+-----+---------+-------+ ... Read More