Computer Programming

Introduction The Aggregate operators compute a single value from a collection. The different Aggregate operators are: Aggregate, Average, Count, LongCount, Max, Min, and Sum. The Aggregate clause calculates a sum value of the values in the collection. The Average clause calculates the average value of the collection of the values. The Count clause counts the elements in the collection. The LongCount clause counts the elements in a large collection. The Max clause determines the maximum value in a collection. The Min clause determines the minimum value of the collection. The Sum clause calculates the sum of values in the collection. The syntax of the Count clause is: For C# public static int Count<T>( this IEnumerable<T> source, Function<T, bool> predicate); The Count clause throws an ArgumentNullException exception, if any argument is null and an OverflowException exception is thrown if the count exceeds the maximum value. The syntax of the Sum clause is: F

CheckboxList is used to provide some options to be select by the user. In this article we will create a list of items and then pass it to view to create a checkbox list. Create two classes with the following format public class CollectionVM {     public List<ChoiceViewModel> ChoicesVM { get; set; }     public List<Int64> SelectedChoices { get; set; } } public class ChoiceViewModel {     public Int64 SNo { get; set; }     public string Text { get; set; } } In controller’s action method write following code in which we will create a new list having some items created below. When we return this ViewModel in the view, we first set the SelectedChoices object to a new blank list of same type. CollectionVM collectionVM = new CollectionVM(); List<ChoiceViewModel> choiceList = new List<ChoiceViewModel>(); choiceList.Add(new ChoiceViewModel() { SNo = 1, Text = "Objective Choice 1" }); choiceList.Add(new ChoiceViewModel() { SNo = 2, Text =

Asp.Net MVC uses such type of classes in which each field may contains specific validation rules using data annotations, to let the user interact with those only. These fields may contains some extra fields to be used as a temporary purpose. Create two classes in the Models folder named Student and Employee as written below: public class Student { public string Name { get; set; } public int Age { get; set; } public string City { get; set; } } public class Employee { public int EmpId { get; set; } public string EmpName { get; set; } } Create a folder in our solution named ViewModels and add a class named Student_EmployeeViewModel which will have the following code. public class Student_EmployeeViewModel { public List<Student> Students { get; set; } public List<Employee> Employees { get; set; } } Come to our Controller (Home controller) and add an Action (Student_Employee) which will be type of HttpGet. This action will have some lines of c

You can rename a table whenever required. The sp_rename stored procedure is used to remaname table. Sp_rename can be used to rename any database object, such as a table,view, stored procedure, or function. The syntax of the sp_rename stored procedure is: Sp_rename old_name, new_name Where, Oldname is the current name of the object. Newname is the new name of the object. The following SQL query renames the EmployeeLeave table: Sp_rename [HumanResources.EmployeeLeave] , [HumanResources.EmployeeVacation] You can also rename a table by right-clicking the Table folder under the Database folder in the Object Employer window and selecting the rename option from the shortcut menu. After a table is created, you may need to see the details of the table. Details of the table include the column names and the constraints. For this purpose, you can use the sp_help command. Dropping a Table At times, when a table is not required, you need to delete a table. A table can be deleted alo

After you create a partition function and a partition scheme, you need to create a table that will store the partition records. You can use the following statements for the same: Create Table EmpPayHistPart ( EmployeeID int, RateChangeDate datetime, Rate money, PayFrequency tinyint, ModifiedDate datetime ) ON RateChangDate (RateChangeDate) In the preceding statement, the RateChangDate refers to the partition scheme that is applied to the RateChangeDate column. The records entered in the EmpPayHistPart table will be stored based on the condition specified in the partition function. Modifying a Table You need to modify tables when there is a requirement to add a new column, alter the data type of a column, or add or remove constraints on the existing columns. For example, Adventure Works stores the leave details of all the employees in the EmployeeLeave table. According to the requirements, you need to add another column named ApprovedBy in the table to store the name of th

A partition function specifies how a table should be partitioned. It specifies the range of values on a particular column. Based on which the table is partitioned. For example, in the scenario of Adventure Works, you can partition the data based on years. The following statement creates a partition function for the same: CREATE PARTITION FUNCTION RateChangDate, (datetime) AS RANGE RIGHT FOR VALUES (‘1996-01-01’, ‘2000-01-01’, ‘2004-01-01’, ‘2008-01-01’) The preceding query creates a partition function named RateChangDate. It specifies that the data pertaining to the change in the payment rate will be partitioned based on the year. Creating a Partition Scheme After setting the partition function, you need to create the partition scheme. A partition scheme associates a partition function with various filegroups resulting in the physical layout of the data. Therefore, before creating a partition scheme, you need to create filegroups. To create partition filegroups, you need to

When the volume of data in a table increases and it takes time to query the data, you can partition the tables and store different parts of the tables in multiple physical locations based on a range of values for a specific column. This helps in managing the data and improving the query performance. Consider the example of a manufacturing organization. The details of inventory movements are stored in the InventoryIssue table. The table contains a large volume of data and the queries take a lot of time to execute thereby slowing the report generation process. To improve the query performance, you can partition the table to divide the data based on a condition and store different parts of the data in different locations. The condition can be based on the date of transaction and you can save the data pertaining to five years at a location. After partitioning the table, data can be retrieved directly from a particular partition by mentioning the partition number in the query. In the

Introduction The Generation operators help in creating a new sequence of values. The Generation operators are DefaultlfEmpty, Empty, Range, and Repeat. The DefaultlfEmpty clause replaces an empty collection with a default single collection. The Empty clause refers to an empty collection. The Range clause generates a collection that contains a sequence of numbers. The Repeat clause generates a collection that contains at least one repeated value. The syntax of Range clause is: For C# public static IEnumerable<int> Range( int start, int count); The Range clause throws an ArgumentOutOfRangeException exception if the count is less than 0, or if the start + or count -1 parameters are larger than the maximum value. The syntax of the Empty clause is: For C# public static IEnumerable<T> Empty<T>(); The Empty clause caches a single empty sequence of the given type. Lets take an simple example <form id="form1" runat="server">     <div

A rule enforces domain integrity for columns or user-defined data types. The rules is applied to the column of the user-defined data type before an INSERT or UPDATE statement is issued. In other words, a rule specifies a restriction on the values of a column or a user-defined data type. Rules are used to implement business-related restrictions or limitations. A rule can be created by using the CREATE RULE statement. The syntax of the CREATE RULE statement is: CREATE RULE rule_name AS conditional_expression Where, Rule_name specifies the name of the new rule that must conform to rules for identifiers. Conditional_expression specifies the condition(s) that defines the rule. It can be any expression that is valid in a WHERE clause and can include elements, such as arithmetic operators, relational operators, IN, LIKE, and BETWEEN. The variable specified in the conditional expression must be prefixed with the @ symbol. The expression refers to the value that is being specified

Relational operators often are used with logical operators (also known as conditional operators sometimes) to construct more complex decision-making expression. The Java programming language supports six conditional operators-five binary and one unary-as shown in the following image. The logical OR operator (||) The logical OR operator (||) combines two expressions which make its operands. The logical OR (||) operator evaluates to Boolean true if either of its operands evaluate to true. This principle is used while testing evaluating expressions. Following are some examples of logical OR operation: (4= =4) || (5 = =8)    results into true because first expression is true. 1 = = 0 || 0 > 1         results into false because neither expression is true (both are false). 5 > 8 || 5 < 2            results into false because both expression are false. 1 < 0 || 8 > 0            results into true because second expression is true. The operator || (logical OR)

In the term relational operator, relational refers to the relationships that values (or operands) can have with one another. Thus, the relational operators determine the relation among different operands. Java provides six relational operator for comparing numbers and characters. But they don’t work with strings. If the comparison is true, the relational expression results into the Boolean value true and to Boolean value false, if the comparison is false. The six relational operators are: < (less than) <= (less than or equal to) == (equal to) > (greater than) >= (greater than or equal to) and != (not equal to) Summarizes the action of these relational operators. t represents true and f represents false. The relational operators have a lower precedence than the arithmetic operators. That means the expression a + 5 > c – 2  ...expression 1 Corresponds to ( a + 5 ) > ( c – 2 ) ...expression 2 And not the following a + ( 5 > c ) -2  …expr

Introduction Conversion operators convert a collection to an array. A Conversion operator changes the type of input objects. The different Conversion operators are ToSequence, ToArray, ToList, ToDictionary, ToLookup, OfType, and Cast. The ToSequence clause simply returns the source argument by changing it to IEnumerable<T>. The ToArray clause enumerates the source sequence and returns an array containing the elements of the sequence. The ToList clause enumerates the source sequence and returns a List<T> containing the elements of the sequence. The ToDictionary clause lists the source sequence and evaluates the keySelector and elementSelector functions for each element to produce the element key and value of the source sequence. The ToLookup clause implements one-to-many dictionary that maps the key to the sequence of values. The OfType clause allocates and returns an enumerable object that captures the source argument. The Cast clause also allocates and returns an enume

Introduction The Set operators in LINQ refer to the query operations that produce a result set. The result is based on the presence or absence of the equivalent elements that are present within the same or separate collection. The Distinct, Union, Intersect, and Except clauses are classified as the Set operators. The Distinct clause removes duplicate values from a collection. The syntax of the Distinct clause is: For C# public static IEnumerable<T> Distinct<T>( this IEnumerabIe<T> source); The Union clause returns the union of two sets. The result elements are the unique elements that are common in the two sets. The syntax of the Union clause is: For C# public static IEnumerabIe<T> Union<T>( this IEnumerabIe<T> source1, IEnumerabIe<T> source2); The Intersect clause returns the set intersection. The elements appear in each of the two collections. The syntax of the Intersect clause is: For C# public static IEnumerabIe<T> Int

Introduction If you want to add hour, minute and seconds in existing time then you should take TimeSpan structure with overload function. Now, you can easily add TimeSpan structure with existing date time object using Add method. Lets take an simple example for demonstration. Step-1 : Add new web form into the project Step-2 : Add one button and label control on it. Step-3 : Handle Button click event. <form id="form1"     runat="server">     <asp:Button ID="Button1"     runat="server"     BackColor="#33CCFF"     onclick="Button1_Click"     Text="Click" />     <div>       <asp:Label ID="Label1"     runat="server"     BackColor="Yellow"></asp:Label>       </div>     </form> Code Behind  protected void Button1_Click(object sender, EventArgs e)         {                       DateTime now = DateTime.Now;                 Ti

Introduction You can show System time as well as universal time through DateTime class. Now, this time you want to show only am and pm text after the current time. You can use "tt" in the ToString ( ) method. Lets create an simple algorithm. Step-1 : Take a web form into the project Step-2 : Add two control (button and label control) onto the form window. Step-3 : Raise button click event Step-4 : Take single instance of DateTime class also pass "tt" parameter in ToString ( ) method. Step-5 : Now Run your application from green triangle button or Ctrl+f5 Complete Source Code <form id="form1" runat="server">     <div>             <asp:Button ID="Button1"          runat="server"          onclick="Button1_Click"          Text="Click"          BackColor="#99CCFF" />       </div>         <asp:Label ID="Label1"         runat="server&

If you want to get first day of next month , use DateTime structure with AddMonths( ) method. using this method you can get first day of next month. Now, create a new instance of DateTime structure with some parameter like DateTime(Int32, Int32, Int32). This parameterized method Initializes a new instance of the DateTime structure to the specified year, month, and day. Here you can pass integer 2 in day field. Now, you can delete 1 day from current DateTime object using AddDays (-1) method. Source Code    <form id="form1" runat="server">     <div>           <asp:Button ID="Button1"         runat="server"         BackColor="#66CCFF"         onclick="Button1_Click"         Text="Click" />       </div>        <asp:Label ID="Label1"        runat="server"        BackColor="Yellow"        Text="Label"></asp:Label>     </form>

Drop down list is a common and usable control in every programming area to let the user can select only one item from the list. In MVC we have to create a list in action method of controller and then pass it through any method like ViewBag and ViewModel etc. Programmer can create required type of list as per the requirements, we will create a SelectListItem type of list because this list provides two property Text and Value by default. Create a simple list of type SelectListItem and add some items (we have added four item here) as added below: List<SelectListItem> items = new List<SelectListItem>(); items.Add(new SelectListItem { Text = "Value 1", Value = "1" }); items.Add(new SelectListItem { Text = "Value 2", Value = "2" }); items.Add(new SelectListItem { Text = "Value 3", Value = "3" }); items.Add(new SelectListItem { Text = "Other", Value = "4" }); Now to pass this to View page

Introduction Using  AddHours  method  you can add Hours in integer, Object will be updated with new date and time. This method is used where you want to calculate time after some time. Like Library management project. Lets take an simple example <form id="form1" runat="server">     <div>           <asp:Button ID="Button1"         runat="server"         BackColor="#66FFFF"         onclick="Button1_Click"         Text="Click" />       </div>         <asp:Label ID="Label1"         runat="server"         BackColor="Yellow"></asp:Label>     </form> Code Behind   protected void Button1_Click(object sender, EventArgs e)         {             DateTime now = DateTime.Now;                       DateTime after3Hours = now.AddHours(3);                         DateTime after4Hours = now.AddHours(4);             Label1.Text = "prese

Introduction Using  AddSeconds  method  you can add seconds in integer, Object will be updated with new date and time. This method is used where you want to calculate time after some seconds. Like Library management project. Lets take an simple example <form id="form1" runat="server">     <asp:Button ID="Button1"     runat="server"     BackColor="#66CCFF"     onclick="Button1_Click" Text="Click" />     <div>       <asp:Label ID="Label1"     runat="server"     BackColor="Yellow"></asp:Label>       </div>     </form> Code Behind   protected void Button1_Click(object sender, EventArgs e)           {                     DateTime now = DateTime.Now;                       DateTime after56Seconds = now.AddSeconds(56);             Label1.Text = "present time = " + now.ToLongTimeString();             Label1.Text += "&

Download this project Project cost : 300Rs or $10 Pay me at: PayPal id : saini1987tarun@gmail.com Via bank transfer ICICI bank account number is :    153801503056 Account holder name is :                 Tarun kumar saini IFSC code is :                                   ICIC0001538 SBBJ bank detail :                             61134658849 Account holder name :                        Tarun kumar saini IFSC code :                                        SBBJ0010398 CONTACT ME narenkumar851@gmail.com Doctor Medicine Prescription system covers the functionality to store the symptoms of the patient’s disease date by date and also the medicines written by the doctor. It is windows form project which may be a setup file to be installed in client’s system. Features of the project: Only authorized person can login into the system and use the software. User can add/modify patients, disease and medicines which will stored in the database. Through this system,

Let the user download a file from server is not a typical task, programmer have to write some lines of code which will execute the task. Asp.Net MVC action with returning type FileResult will complete this task in few task listed in the article. After uploading file/files on the server, how to deliver/serve a file for user to download and save on an individual system depends on the way of storing the file on the server by programmer. Programmer can provide a simple link to an action including some lines of code to perform the task. In the controller write below line of c# code in the action named “DownloadFile” which will access the file saved on the root of this project and then prompt user to Open/Save that file. public FileResult DownloadFile() { var file = Server.MapPath("~/download file.txt"); return File(file, "Text", "download file"); } These two line of code will sufficient to prompt the user, now in view page create an actionline w

Programmer need to check whether the file is selected by the user or not, when uploading a file. If user will not upload any file and submit the form, the code will throw an exception with description like "file must not be null". To overcome this issue programmer have to check the uploaded file before the form submission, and this can be performed by using Java script. Write the following code in our view where the file upload control is placed: function validateForm() { if ($("#file").val() == "") { alert("Please select a file"); return false; } } Here “#file” is the id of file upload control and we are checking the value of this control. If the value is empty then it will alert with the message shown and return back to the form. If this control will have file then it will submit the form. On the submit button, just call this function to execute this code with Onclick=”validateForm();”. Now to select only some file types w