Show Mulitiple Markers on Google Map

Here is an example through which u can learn how to show more than one marker on google map.
First of all take a div to show the map on your aspx page like this :-

 <div id="map" style="width: 500px; height: 400px;"></div>

After that you have to add a google api which will display the google map on  your div portion:-

<script src="http://maps.google.com/maps/api/js?sensor=false" type="text/javascript">

Now add this script on client side:- In this i am adding six locations on variable locations and setting other properties of map like zoom level,center,maptype.
Also i am showing infowindow on click of marker for which i took variable infowindow.
Set the below script on your page and you will be able to show multiple markers:--




<script type="text/javascript">
    var locations = [
      ['Chawri Bazaar', 28.649319,77.224417],
      ['Shivaji Bridge', 28.636212,77.226648],
      ['Rajeev chock Metro', 28.633199,77.21858],
      ['Jhandewalan', 28.644498,77.207594],
      ['Chandni Chock Metro',28.657755,77.228022],
      ['Delhi Junction Railway',28.661972,77.237806]
    ];

    var map = new google.maps.Map(document.getElementById('map'), {
      zoom: 13,
      center: new google.maps.LatLng(28.649319,77.224417),
      mapTypeId: google.maps.MapTypeId.ROADMAP
    });

    var infowindow = new google.maps.InfoWindow();

    var marker, i;

    for (i = 0; i < locations.length; i++) { 
      marker = new google.maps.Marker({
        position: new google.maps.LatLng(locations[i][1], locations[i][2]),
        map: map
      });

      google.maps.event.addListener(marker, 'click', (function(marker, i) {
        return function() {
          infowindow.setContent(locations[i][0]);
          infowindow.open(map, marker);
        }
      })(marker, i));
    }
  </script>



Hope this example will help you to complete your purpose. :)

MySql Database Interview Questions

1.      What's MySQL ?
MySQL (pronounced "my ess cue el") is an open source relational database management system (RDBMS) that uses Structured Query Language (SQL), the most popular language for adding, accessing, and processing data in a database. Because it is open source, anyone can download MySQL and tailor it to their needs in accordance with the general public license. MySQL is noted mainly for its speed, reliability, and flexibility.

2. What’s the default port for MySQL Server? - 3306
3. What does tee command do in MySQL? - tee followed by a filename turns on MySQL logging to a specified file. It can be stopped by command notee.
4. Can you save your connection settings to a conf file? - Yes, and name it ~/.my.conf. You might want to change the permissions on the file to 600, so that it’s not readable by others.
5. How do you start and stop MySQL on Windows? - net start MySQL, net stop MySQL
6. How do you start MySQL on Linux? - /etc/init.d/mysql start
7. Explain the difference between mysql and mysqli interfaces in PHP? - mysqli is the object-oriented version of mysql library functions.
8. What are some good ideas regarding user security in MySQL? - There is no user without a password. There is no user without a user name. There is no user whose Host column contains % (which here indicates that the user can log in from anywhere in the network or the Internet). There are as few users as possible (in the ideal case only root) who have unrestricted access.
9. Explain the difference between MyISAM Static and MyISAM Dynamic. - In MyISAM static all the fields have fixed width. The Dynamic MyISAM table would include fields such as TEXT, BLOB, etc. to accommodate the data types with various lengths. MyISAM Static would be easier to restore in case of corruption, since even though you might lose some data, you know exactly where to look for the beginning of the next record.
10. How do you change a password for an existing user via mysqladmin? - mysqladmin -u root -p password "newpassword"
11. Use mysqldump to create a copy of the database? - mysqldump -h mysqlhost -u username -p mydatabasename > dbdump.sql
12. What does myisamchk do? - It compressed the MyISAM tables, which reduces their disk usage.
13. Explain advantages of InnoDB over MyISAM? - Row-level locking, transactions, foreign key constraints and crash recovery.
14. Explain advantages of MyISAM over InnoDB? - Much more conservative approach to disk space management - each MyISAM table is stored in a separate file, which could be compressed then with myisamchk if needed. With InnoDB the tables are stored in tablespace, and not much further optimization is possible. All data except for TEXT and BLOB can occupy 8,000 bytes at most. No full text indexing is available for InnoDB. TRhe COUNT(*)s execute slower than in MyISAM due to tablespace complexity.
15. What are HEAP tables in MySQL? - HEAP tables are in-memory. They are usually used for high-speed temporary storage. No TEXT or BLOB fields are allowed within HEAP tables. You can only use the comparison operators = and <=>. HEAP tables do not support AUTO_INCREMENT. Indexes must be NOT NULL.
16. How do you control the max size of a HEAP table? - MySQL config variable max_heap_table_size.
17. What are CSV tables? - Those are the special tables, data for which is saved into comma-separated values files. They cannot be indexed.
18. But what if you really want to store the timestamp data, such as the publication date of the article? - Create two columns of type TIMESTAMP and use the second one for your real data.
19. Explain data type TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP - The column exhibits the same behavior as a single timestamp column in a table with no other timestamp columns.
20. What does TIMESTAMP ON UPDATE CURRENT_TIMESTAMP data type do? - On initialization places a zero in that column, on future updates puts the current value of the timestamp in.
21. Explain TIMESTAMP DEFAULT ‘2006:09:02 17:38:44′ ON UPDATE CURRENT_TIMESTAMP. - A default value is used on initialization, a current timestamp is inserted on update of the row.
22. If I created a column with data type VARCHAR(3), what would I expect to see in MySQL table? - CHAR(3), since MySQL automatically adjusted the data type.

23.  How can you see all indexes defined for a table?
SHOW INDEX FROM <TableName>;

24. Explain federated tables. - Introduced in MySQL 5.0, federated tables allow access to the tables located on other databases on other servers.
25. What is SERIAL data type in MySQL? - BIGINT NOT NULL PRIMARY KEY AUTO_INCREMENT
26. What happens when the column is set to AUTO INCREMENT and you reach the maximum value for that table? - It stops incrementing. It does not overflow to 0 to prevent data losses, but further inserts are going to produce an error, since the key has been used already.
27. Explain the difference between BOOL, TINYINT and BIT. - Prior to MySQL 5.0.3: those are all synonyms. After MySQL 5.0.3: BIT data type can store 8 bytes of data and should be used for binary data.
28. Explain the difference between FLOAT, DOUBLE and REAL. - FLOATs store floating point numbers with 8 place accuracy and take up 4 bytes. DOUBLEs store floating point numbers with 16 place accuracy and take up 8 bytes. REAL is a synonym of FLOAT for now.
29. If you specify the data type as DECIMAL (5,2), what’s the range of values that can go in this table? - 999.99 to -99.99. Note that with the negative number the minus sign is considered one of the digits.
30. What happens if a table has one column defined as TIMESTAMP? - That field gets the current timestamp whenever the row gets altered.
31. How would you delete a column?
    ALTER TABLE <Thakur_test> DROP  Thakur_column   .

When would you use ORDER BY in DELETE statement?
When you’re not deleting by row ID. Such as in DELETE FROM  <Thakur_table> ORDER BY timestamp LIMIT 1. This will delete the most recently posted question in the table <Thakur_table> .

33.  Top of Form 33.  What is DDL, DML and DCL ? If you look at the large variety of SQL commands, they can be divided into three large subgroups. Data Definition Language deals with database schemas and descriptions of how the data should reside in the database, therefore language statements like CREATE TABLE or ALTER TABLE belong to DDL. DML deals with data manipulation, and therefore includes most common SQL statements such SELECT, INSERT, etc. Data Control Language includes commands such as GRANT, and mostly concerns with rights, permissions and other controls of the database system. 34.  How do you get the number of rows affected by query? SELECT COUNT (user_id) FROM users would only return the number of user_id’s. 35.  If the value in the column is repeatable, how do you find out the unique values? Use DISTINCT in the query, such as SELECT DISTINCT user_firstname FROM users; You can also ask for a number of distinct values by saying SELECT COUNT (DISTINCT user_firstname) FROM users; 36.  How do you return the a hundred books starting from 25th? SELECT book_title FROM books LIMIT 25, 100. The first number in LIMIT is the offset, the second is the number. 37.  You wrote a search engine that should retrieve 10 results at a time, but at the same time you’d like to know how many rows there’re total. How do you display that to the user? SELECT SQL_CALC_FOUND_ROWS page_title FROM web_pages LIMIT 1,10; SELECT FOUND_ROWS(); The second query (not that COUNT() is never used) will tell you how many results there’re total, so you can display a phrase "Found 13,450,600 results, displaying 1-10". Note that FOUND_ROWS does not pay attention to the LIMITs you specified and always returns the total number of rows affected by query. 38.  How would you write a query to select all teams that won either 2, 4, 6 or 8 games? SELECT team_name FROM teams WHERE team_won IN (2, 4, 6, 8) 39.  How would you select all the users, whose phone number is null? SELECT user_name FROM users WHERE ISNULL(user_phonenumber); 40.  What does this query mean: SELECT user_name, user_isp FROM users LEFT JOIN isps USING (user_id) ? It’s equivalent to saying SELECT user_name, user_isp FROM users LEFT JOIN isps WHERE users.user_id=isps.user_id 41.  How do you find out which auto increment was assigned on the last insert? 42.  SELECT LAST_INSERT_ID() will return the last value assigned by the auto_increment function. Note that you don’t have to specify the table name. 43.  What does –i-am-a-dummy flag to do when starting MySQL? Makes the MySQL engine refuse UPDATE and DELETE commands where the WHERE clause is not present. 44.  On executing the DELETE statement I keep getting the error about foreign key constraint failing. What do I do? What it means is that so of the data that you’re trying to delete is still alive in another table. Like if you have a table for universities and a table for students, which contains the ID of the university they go to, running a delete on a university table will fail if the students table still contains people enrolled at that university. Proper way to do it would be to delete the offending data first, and then delete the university in question. Quick way would involve running SET foreign_key_checks=0 before the DELETE command, and setting the parameter back to 1 after the DELETE is done. If your foreign key was formulated with ON DELETE CASCADE, the data in dependent tables will be removed automatically.

ASP.NET C# Interview Questions

Q1. What type of code (server or client) is found in a Code-Behind class?
Ans. Server side code.  

Q2. Explain the differences between Server-side and Client-side code?
Ans. Server side code will execute at server (where the website is hosted) end, & all the business logic will execute at server end where as client side code will execute at client side (usually written in javascript, vbscript, jscript) at browser end.

Q3. Which property of a validation control is used to associate it with a server control on that page?
Ans. ControlToValidate property.

Q4. How to make sure that value is entered in an asp:Textbox control?
Ans. Use a RequiredFieldValidator control.

Q5. Which method is invoked on the DataAdapter control to load the generated dataset with data?
Ans. Fill() method.

Q6. How would you implement inheritance using VB.NET & C#?
Ans. C# Derived Class : Baseclass
VB.NEt : Derived Class Inherits Baseclass

Q7. What method is used to explicitly kill a user's session?
Ans. Session.Abandon()

Q8. What property within the asp:gridview control is changed to bind columns manually?
Ans. Autogenerated columns is set to false

Q9. Which method is used to redirect the user to another page without performing a round trip to the client?
Ans. Server.Transfer method.

Q10. How do we use different versions of private assemblies in same application without re-build?
Ans.Inside the Assemblyinfo.cs or Assemblyinfo.vb file, we need to specify assembly version.
assembly: AssemblyVersion

Q11. Is it possible to debug java-script in .NET IDE? If yes, how?
Ans. Yes, simply write "debugger" statement at the point where the breakpoint needs to be set within the javascript code and also enable javascript debugging in the browser property settings.

Q12. How many ways can we maintain the state of a page?
Ans. 1. Client Side - Query string, hidden variables, viewstate, cookies
2. Server side - application , cache, context, session, database

Q13. What is the use of a multicast delegate?
Ans. A multicast delegate may be used to call more than one method.

Q14. What is the use of a private constructor?
Ans. A private constructor may be used to prevent the creation of an instance for a class.

Q15. What is the use of Singleton pattern?
Ans. A Singleton pattern .is used to make sure that only one instance of a class exists.

Q16. When do we use a DOM parser and when do we use a SAX parser?
Ans. The DOM Approach is useful for small documents in which the program needs to process a large portion of the document whereas the SAX approach is useful for large documents in which the program only needs to process a small portion of the document.

Q17. Will the finally block be executed if an exception has not occurred?
Ans.Yes it will execute.

Q18. What is a Dataset?
Ans. A dataset is an in memory database kindof object that can hold database information in a disconnected environment.

Q19. Is XML a case-sensitive markup language?
Ans. Yes.

Q20. What is an .ashx file?
Ans. It is a web handler file that produces output to be consumed by an xml consumer client (rather than a browser).

Q21. What is encapsulation?
Ans. Encapsulation is the OOPs concept of binding the attributes and behaviors in a class, hiding the implementation of the class and exposing the functionality.

Q22. What is Overloading?
Ans. When we add a new method with the same name in a same/derived class but with different number/types of parameters, the concept is called overluoad and this ultimately implements Polymorphism.

Q23. What is Overriding?
Ans. When we need to provide different implementation in a child class than the one provided by base class, we define the same method with same signatures in the child class and this is called overriding.

Q24. What is a Delegate?
Ans. A delegate is a strongly typed function pointer object that encapsulates a reference to a method, and so the function that needs to be invoked may be called at runtime.

Q25. Is String a Reference Type or Value Type in .NET?
Ans. String is a Reference Type object.

Q26. What is a Satellite Assembly?
Ans. Satellite assemblies contain resource files corresponding to a locale (Culture + Language) and these assemblies are used in deploying an application globally for different languages.

Q27. What are the different types of assemblies and what is their use?
Ans. Private, Public(also called shared) and Satellite Assemblies.

Q28. Are MSIL and CIL the same thing?
Ans. Yes, CIL is the new name for MSIL.

Q29. What is the base class of all web forms?
Ans. System.Web.UI.Page

Q30. How to add a client side event to a server control?
Ans. Example... BtnSubmit.Attributes.Add("onclick","javascript:fnSomeFunctionInJavascript()");

Q31. How to register a client side script from code-behind?
Ans. Use the Page.RegisterClientScriptBlock method in the server side code to register the script that may be built using a StringBuilder.

Q32. Can a single .NET DLL contain multiple classes?
Ans. Yes, a single .NET DLL may contain any number of classes within it.

Q33. What is DLL Hell?
Ans. DLL Hell is the name given to the problem of old unmanaged DLL's due to which there was a possibility of version conflict among the DLLs.

Q34. can we put a break statement in a finally block?
Ans. The finally block cannot have the break, continue, return and goto statements.

Q35. What is a CompositeControl in .NET?
Ans. CompositeControl is an abstract class in .NET that is inherited by those web controls that contain child controls within them.

Q36. Which control in asp.net is used to display data from an xml file and then displayed using XSLT?
Ans. Use the asp:Xml control and set its DocumentSource property for associating an xml file, and set its TransformSource property to set the xml control's xsl file for the XSLT transformation.

Q37. Can we run ASP.NET 1.1 application and ASP.NET 2.0 application on the same computer?
Ans. Yes, though changes in the IIS in the properties for the site have to be made during deployment of each.

Q38. What are the new features in .NET 2.0?
Ans. Plenty of new controls, Generics, anonymous methods, partial classes, iterators, property visibility (separate visibility for get and set) and static classes.

Q39. Can we pop a MessageBox in a web application?
Ans. Yes, though this is done clientside using an alert, prompt or confirm or by opening a new web page that looks like a messagebox.

Q40. What is managed data?
Ans. The data for which the memory management is taken care by .Net runtime’s garbage collector, and this includes tasks for allocation de-allocation.

Q41. How to instruct the garbage collector to collect unreferenced data?
Ans. We may call the garbage collector to collect unreferenced data by executing the System.GC.Collect() method.

Q42. How can we set the Focus on a control in ASP.NET?
Ans. txtBox123.Focus(); OR Page.SetFocus(NameOfControl);

Q43. What are Partial Classes in Asp.Net 2.0?
Ans. In .NET 2.0, a class definition may be split into multiple physical files but partial classes do not make any difference to the compiler as during compile time, the compiler groups all the partial classes and treats them as a single class.

Q44. How to set the default button on a Web Form?
Ans. <asp:form id="form1" runat="server" defaultbutton="btnGo"/>

Q45.Can we force the garbage collector to run?
Ans. Yes, using the System.GC.Collect(), the garbage collector is forced to run in case required to do so.

Q46. What is Boxing and Unboxing?
Ans. Boxing is the process where any value type can be implicitly converted to a reference type object while Unboxing is the opposite of boxing process where the reference type is converted to a value type.

Q47. What is Code Access security? What is CAS in .NET?
Ans. CAS is the feature of the .NET security model that determines whether an application or a piece of code is permitted to run and decide the resources it can use while running.

Q48. What is Multi-tasking?
Ans. It is a feature of operating systems through which multiple programs may run on the operating system at the same time, just like a scenario where a Notepad, a Calculator and the Control Panel are open at the same time.

Q49. What is Multi-threading?
Ans. When an application performs different tasks at the same time, the application is said to exhibit multithreading as several threads of a process are running.2

Q50. What is a Thread?
Ans. A thread is an activity started by a process and its the basic unit to which an operating system allocates processor resources.

Q51. What does AddressOf in VB.NET operator do?
Ans. The AddressOf operator is used in VB.NET to create a delegate object to a method in order to point to it.

Q52. How to refer to the current thread of a method in .NET?
Ans. In order to refer to the current thread in .NET, the Thread.CurrentThread method can be used. It is a public static property.

Q53. How to pause the execution of a thread in .NET?
Ans. The thread execution can be paused by invoking the Thread.Sleep(IntegerValue) method where IntegerValue is an integer that determines the milliseconds time frame for which the thread in context has to sleep.

Q54. How can we force a thread to sleep for an infinite period?
Ans. Call the Thread.Interupt() method.

Q55. What is Suspend and Resume in .NET Threading?
Ans. Just like a song may be paused and played using a music player, a thread may be paused using Thread.Suspend method and may be started again using the Thread.Resume method. Note that sleep method immediately forces the thread to sleep whereas the suspend method waits for the thread to be in a persistable position before pausing its activity.

Q56. How can we prevent a deadlock in .Net threading?
Ans. Using methods like Monitoring, Interlocked classes, Wait handles, Event raising from between threads, using the ThreadState property.

Q57. What is Ajax?
Ans. Asyncronous Javascript and XML - Ajax is a combination of client side technologies that sets up asynchronous communication between the user interface and the web server so that partial page rendering occur instead of complete page postbacks.

Q58. What is XmlHttpRequest in Ajax?
Ans. It is an object in Javascript that allows the browser to communicate to a web server asynchronously without making a postback.

Q59. What are the different modes of storing an ASP.NET session?
Ans. InProc (the session state is stored in the memory space of the Aspnet_wp.exe process but the session information is lost when IIS reboots), StateServer (the Session state is serialized and stored in a separate process call Viewstate is an object in .NET that automatically persists control setting values across the multiple requests for the same page and it is internally maintained as a hidden field on the web page though its hashed for security reasons.

Q60. What is a delegate in .NET?
Ans. A delegate in .NET is a class that can have a reference to a method, and this class has a signature that can refer only those methods that have a signature which complies with the class.

Q61. Is a delegate a type-safe functions pointer?
Ans. Yes

Q62. What is the return type of an event in .NET?
Ans. There is No return type of an event in .NET.

Q63. Is it possible to specify an access specifier to an event in .NET?
Ans. Yes, though they are public by default.

Q64. Is it possible to create a shared event in .NET?
Ans. Yes, but shared events may only be raised by shared methods.

Q65. How to prevent overriding of a class in .NET?
Ans. Use the keyword NotOverridable in VB.NET and sealed in C#.

Q66. How to prevent inheritance of a class in .NET?
Ans. Use the keyword NotInheritable in VB.NET and sealed in C#.

Q67. What is the purpose of the MustInherit keyword in VB.NET?
Ans. MustInherit keyword in VB.NET is used to create an abstract class.

Q68. What is the access modifier of a member function of in an Interface created in .NET?
Ans. It is always public, we cant use any other modifier other than the public modifier for the member functions of an Interface.

Q69. What does the virtual keyword in C# mean?
Ans. The virtual keyword signifies that the method and property may be overridden.

Q70. How to create a new unique ID for a control?
Ans. ControlName.ID = "ControlName" + Guid.NewGuid().ToString(); //Make use of the Guid class

Q71A. What is a HashTable in .NET?
Ans. A Hashtable is an object that implements the IDictionary interface, and can be used to store key value pairs. The key may be used as the index to access the values for that index.

Q71B. What is an ArrayList in .NET?
Ans. Arraylist object is used to store a list of values in the form of a list, such that the size of the arraylist can be increased and decreased dynamically, and moreover, it may hold items of different types. Items in an arraylist may be accessed using an index.

Q72. What is the value of the first item in an Enum? 0 or 1?
Ans. 0

Q73. Can we achieve operator overloading in VB.NET?
Ans. Yes, it is supported in the .NET 2.0 version, the "operator" keyword is used.

Q74. What is the use of Finalize method in .NET?
Ans. .NET Garbage collector performs all the clean up activity of the managed objects, and so the finalize method is usually used to free up the unmanaged objects like File objects, Windows

API objects, Database connection objects, COM objects etc.

Q75. How do you save all the data in a dataset in .NET?
Ans. Use the AcceptChanges method which commits all the changes made to the dataset since last time Acceptchanges was performed.

Q76. Is there a way to suppress the finalize process inside the garbage collector forcibly in .NET?
Ans. Use the GC.SuppressFinalize() method.

Q77. What is the use of the dispose() method in .NET?
Ans. The Dispose method in .NET belongs to IDisposable interface and it is best used to release unmanaged objects like File objects, Windows API objects, Database connection objects, COM objects etc from the memory. Its performance is better than the finalize() method.

Q78. Is it possible to have have different access modifiers on the get and set methods of a property in .NET?
Ans. No we can not have different modifiers of a common property, which means that if the access modifier of a property's get method is protected, and it must be protected for the set method as well.

Q79. In .NET, is it possible for two catch blocks to be executed in one go?
Ans. This is NOT possible because once the correct catch block is executed then the code flow goes to the finally block.

Q80. Is there any difference between System.String and System.StringBuilder classes?
Ans. System.String is immutable by nature whereas System.StringBuilder can have a mutable string in which plenty of processes may be performed.