Skip to main content

Featured Post

How to use Tabs in ASP.NET CORE

I want to show Components in a tabs , so first of all create few components. In this project we have three components, First View Component  public class AllViewComponent : ViewComponent     {         private readonly UserManager<ApplicationUser> _userManager;         public AllViewComponent(UserManager<ApplicationUser> userManager)         {             _userManager = userManager;         }         public async Task<IViewComponentResult> InvokeAsync()         {             List<StudentViewModel> allUsers = new List<StudentViewModel>();             var items = await _userManager.Users.ToListAsync();             foreach (var item in items)             {                 allUsers.Add(new StudentViewModel {Id=item.Id, EnrollmentNo = item.EnrollmentNo, FatherName = item.FatherName, Name = item.Name, Age = item.Age, Birthdate = item.Birthdate, Address = item.Address, Gender = item.Gender, Email = item.Email });             }            

How to Delete Data from Table or Related Table, SQL

Programmer need to delete data from the database when it is no longer required. The smallest unit that can be deleted from a database is a row. You can delete a row from a table by using the DELETE DML statement. The syntax of the DELETE statement is:

DELETE [FROM] table_name
[FROM table (s)]
[WHERE condition]
Where,

  • Table_name specifies the name of the table from which you have to delete rows.
  • Table_name specifies the name of the table(s) required to set the condition for deletion.
  • Condition specifies the condition that identifies the row(s) to be deleted.

For example, the following statement deletes the address details of AddressID 104 from the Address table:

DELETE Address
WHERE AddressID = ‘104’

Deleting Data from Related Tables

While deleting records form related tables, you need to ensure that you first delete the records from the table that contain the foreign key and then from the table that contains the primary key.

Consider the example of the Adventure Works. The Employee table contains data of those employees who have retired from the company. This data is not required anymore. This increases the size of the database.

You are required to ensure that this old data is removed from the Employee table. You can delete this data by using the following SQL statement:

DELETE FROM HumanResources.Employee
WHERE BirthDate < dateadd (yy, -60, getdate ())

The database contains tables related to the Employee table. The related tables are HumanResources.EmployeeAddress, HumanResources.EmployeeDepartmentHistory, HumanResources.EmployeePayHistory, and HumanResources.JobCandidate. The EmployeeID attribute in these tables is a foreign key to the EmployeeID attribute of the Employee table. Therefore, the query results in an error. Therefore, you need to delete data from the related tables before executing the preceding DELETE statement.

Deleting All the Records from a Table

As a database developer, you might need to delete all the records from a table. You can do this by using the following DELETE statement:

DELETE table_name

You can also use the TRUNCATE DML statement. The syntax of the TRUNCATE statement is:
TRUNCATE TABLE table_name
Where,

  • Table_name specifies the name of the table from which you have to delete rows. However, TRUNCATE TABLE is executed faster.

TRUNCATE TABLE does not support the WHERE clause. In addition, the TRUNCATE TABLE statement does no fire a trigger. When truncate is used, the deleted rows are not entered in the transaction log.
For example, the following statement deletes all the records from the Address table:
TRANCATE TABLE Address

Manipulate XML Data and Parsing with XML document.

Comments

Popular Post

Polynomial representation using Linked List for Data Structure in 'C'

Polynomial representation using Linked List The linked list can be used to represent a polynomial of any degree. Simply the information field is changed according to the number of variables used in the polynomial. If a single variable is used in the polynomial the information field of the node contains two parts: one for coefficient of variable and the other for degree of variable. Let us consider an example to represent a polynomial using linked list as follows: Polynomial:      3x 3 -4x 2 +2x-9 Linked List: In the above linked list, the external pointer ‘ROOT’ point to the first node of the linked list. The first node of the linked list contains the information about the variable with the highest degree. The first node points to the next node with next lowest degree of the variable. Representation of a polynomial using the linked list is beneficial when the operations on the polynomial like addition and subtractions are performed. The resulting polynomial can also

How to use Tabs in ASP.NET CORE

I want to show Components in a tabs , so first of all create few components. In this project we have three components, First View Component  public class AllViewComponent : ViewComponent     {         private readonly UserManager<ApplicationUser> _userManager;         public AllViewComponent(UserManager<ApplicationUser> userManager)         {             _userManager = userManager;         }         public async Task<IViewComponentResult> InvokeAsync()         {             List<StudentViewModel> allUsers = new List<StudentViewModel>();             var items = await _userManager.Users.ToListAsync();             foreach (var item in items)             {                 allUsers.Add(new StudentViewModel {Id=item.Id, EnrollmentNo = item.EnrollmentNo, FatherName = item.FatherName, Name = item.Name, Age = item.Age, Birthdate = item.Birthdate, Address = item.Address, Gender = item.Gender, Email = item.Email });             }            

Memory representation of Linked List Data Structures in C Language

                                 Memory representation of Linked List              In memory the linked list is stored in scattered cells (locations).The memory for each node is allocated dynamically means as and when required. So the Linked List can increase as per the user wish and the size is not fixed, it can vary.                Suppose first node of linked list is allocated with an address 1008. Its graphical representation looks like the figure shown below:       Suppose next node is allocated at an address 506, so the list becomes,   Suppose next node is allocated with an address with an address 10,s the list become, The other way to represent the linked list is as shown below:  In the above representation the data stored in the linked list is “INDIA”, the information part of each node contains one character. The external pointer root points to first node’s address 1005. The link part of the node containing information I contains 1007, the address of