Monday, 2 April 2018
Sunday, 1 April 2018
Group function and aggregate function
Group function and
aggregate function
SQL group function or
aggregate function retuns single value from the group.
These are built in
function in sql and oracle
Aggegate function.
Min – This function
is used to get the mimimum value from the specified column
Max- This function is
used to get the maximum value from the specified column
Sum- This function is
used to get the sum if numeric column
Count- This function
is used to get the actual number of values (count) from the
column
Avg- this function
used to get the average value from the column.
Group function
Distinct
The distinct ()
function is used to get the disctinct record from the column.
select distinct(TitleOfCourtesy) from Employees
Inheritance Code
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ConsoleApplicationSecondTry
{
class Program
{
static void Main(string[] args)
{
/*
* We have two classes A and B.
* Class B inherits class B.
* if we create object of class A (
Which points to the class A // A O = new
A(); // ) then
* We can call and access the base
class (Class A) Methods and data members
*/
A O = new A();
O.Method_In_A();
O.a = 20;
/*
* We have two classes A and B.
* Class B inherits class B.
* if we create object of class A (
Which points to the class B // A O1 =
new B(); // ) then
* We can call and access the base
class (Class A) Methods and data members
* In this case the constructor of
base class is called and we can assign the value to base class public data
members(Inheritance - Is relationship ).
*/
A O1 = new B();
O1.a = 30;
O1.Method_In_A();
/*
* We have two classes A and B.
* Class B inherits class B.
* if we create object of class B (
Which points to the class B // B O2 =
new B(); // ) then have access to all public methods and data members.
*/
B O2 = new B();
O2.a = 50;
O2.b = 60;
O2.Method_In_A();
O2.Method_In_B();
/*
* We have two classes A and B.
* Class B inherits class B.
* if we create object of class B (
Which points to the class A // B O3 =
new A(); // ) then we get error as an explicit conversion exist (Inheritance
concept).
* below line will not work.
*/
//B O3 = new A();
Console.ReadLine();
}
}
class A
{
public int a = 10;
public A()
{
Console.WriteLine("Constructor
Of A");
}
public A(int i)
{
i
= a;
Console.WriteLine("Param
Constructor Of A", i);
}
public void
Method_In_A()
{
Console.WriteLine("Method
in A Called.");
}
}
class B : A
{
public int b = 10;
public B()
{
Console.WriteLine("Constructor
Of B");
}
public B(int i)
{
i
= b;
Console.WriteLine("Param
Constructor Of B", i);
}
public void
Method_In_B()
{
Console.WriteLine("Method
in B Called.");
}
}
}
Thursday, 22 March 2018
Having clause
Having clause
Having clause is similar to the where clause but it is used
in the conjuction with group by clause in select statement
Group by clause with having clause used to filter the data
or recordset.
Having
clause folloed by group by and preced order by clause if used.
Following
is the position of having clause
Select
From
Where
Group by
Having
Order by
Eg.
select
TitleOfCourtesy from Employees
group by TitleOfCourtesy,BirthDate
having BirthDate >= CONVERT(datetime,'1950-10-12',101)
select
TitleOfCourtesy from Employees
group by TitleOfCourtesy,BirthDate
having BirthDate >= '1960-10-12'
Monday, 19 March 2018
SQL Joins
SQL Join
SQL join is used to get the data from two or more table in
the database.
A relation between the table is maintained by using the PK
and FK reference.
We can retrieve the
data from two or more table using joins which containg some common values in
both the table.
SQL join types
Inner join - Retrieve the data from two or more table when
there is matching records in both the table.
select a.FirstName,a.LastName, b.OrderID,b.ShipName,b.CustomerID
from
Employees a
inner join
Orders b
on
a.EmployeeID = b.EmployeeID
order by
a.FirstName
Left join - Retrive all the data from left table with
matching records on right table
select a.FirstName,a.LastName, b.OrderID,b.ShipName,b.CustomerID
from
Employees a
left join
Orders b
on
a.EmployeeID = b.EmployeeID
order by
a.FirstName
Right join – Retrive
all the data from right table with matching records on left table.
select a.FirstName,a.LastName, b.OrderID,b.ShipName,b.CustomerID
from
Employees a
right join
Orders b
on
a.EmployeeID = b.EmployeeID
order by
a.FirstName
Full join - retrive data when there is matching records
in one of the table.
select a.FirstName,a.LastName, b.OrderID,b.ShipName,b.CustomerID
from
Employees a
full join
Orders b
on
a.EmployeeID = b.EmployeeID
order by
a.FirstName
Self join - is
used to join a table to itself as if the table were two tables, temporarily
renaming at least one table in the SQL statement.
Cartesian join - returns
the Cartesian product of the sets of
records from the two or more joined tables.
Friday, 16 March 2018
Cursor
Cursor
A cursor is a temporary work area created in the system
memory when a SQL statement is executed. A cursor contains information on a
select statement and the rows of data accessed by it.
This temporary work area is
used to store the data retrieved from the database, and manipulate this data. A
cursor can hold more than one row, but can process only one row at a time. The
set of rows the cursor holds is called the active set.
There are two types of cursors in PL/SQL:
Implicit cursors
These are created by default
when DML statements like, INSERT, UPDATE, and DELETE statements are executed.
They are also created when a SELECT statement that returns just
one row is executed.
Explicit cursors
They must be created when you
are executing a SELECT statement that returns more than one row. Even though
the cursor stores multiple records, only one record can be processed at a time,
which is called as current row. When you fetch a row the current row position
moves to next row.
The cursor attributes available are
%FOUND
%NOTFOUND
%ROWCOUNT
%ISOPEN.
The status of the cursor for each of these attributes are
defined in the below table.
|
Attributes
|
Return Value
|
Example
|
|
%FOUND
|
The return value is
TRUE, if the DML statements like INSERT, DELETE and UPDATE affect at least
one row and if SELECT ….INTO statement return at least one row.
|
SQL%FOUND
|
|
The return value is
FALSE, if DML statements like INSERT, DELETE and UPDATE do not affect row and
if SELECT….INTO statement do not return a row.
|
||
|
%NOTFOUND
|
The return value is
FALSE, if DML statements like INSERT, DELETE and UPDATE at least one row and
if SELECT ….INTO statement return at least one row.
|
SQL%NOTFOUND
|
|
The return value is
TRUE, if a DML statement like INSERT, DELETE and UPDATE do not affect even
one row and if SELECT ….INTO statement does not return a row.
|
||
|
%ROWCOUNT
|
Return the number of
rows affected by the DML operations INSERT, DELETE, UPDATE, SELECT
|
SQL%ROWCOUNT
|
For Example: Consider the PL/SQL Block that uses implicit cursor
attributes as shown below:
DECLARE var_rows number(5);
BEGIN
UPDATE employee
SET salary = salary + 1000;
IF SQL%NOTFOUND THEN
dbms_output.put_line('None of the salaries
where updated');
ELSIF SQL%FOUND THEN
var_rows := SQL%ROWCOUNT;
dbms_output.put_line('Salaries for ' ||
var_rows || 'employees are updated');
END IF;
END;
In the above PL/SQL Block, the salaries of all the employees in the
‘employee’ table are updated. If none of the employee’s salary are updated we
get a message 'None of the salaries where updated'. Else we get a message like
for example, 'Salaries for 1000 employees are updated' if there are 1000 rows
in ‘employee’ table. Friday, 9 March 2018
Use of caching in Asp.net (GidView Demo)
Post Content
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Xml;
using System.Data;
using System.IO;
using System.Web.Caching;
public partial class _Default : System.Web.UI.Page
{
string strXmlAllDetails = string.Empty;
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
getData();
}
}
public DataSet getData()
{
DataSet dsAllDetailsOutput = (DataSet)Cache["mydata"];
dsAllDetailsOutput = new DataSet();
WebServiceDemoExample objWebServiceDemoExample = new WebServiceDemoExample();
string strXmlOutput = objWebServiceDemoExample.FetchAllDetailsAdmin();
XmlReader objXmlReader = System.Xml.XmlReader.Create(new StringReader(strXmlOutput));
dsAllDetailsOutput.ReadXml(objXmlReader);
Cache.Insert("mydata", dsAllDetailsOutput, new CacheDependency(Server.MapPath("")), DateTime.Now.AddHours(12), Cache.NoSlidingExpiration);
if (dsAllDetailsOutput.Tables.Count > 0)
{
if (dsAllDetailsOutput.Tables[0].Rows.Count > 0)
{
GridView1.DataSource = dsAllDetailsOutput;
GridView1.DataBind();
}
}
return dsAllDetailsOutput;
}
protected void GridView1_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
DataSet ds = (DataSet)Cache["mydata"];
GridView1.PageIndex = e.NewPageIndex;
GridView1.DataSource = ds;
GridView1.DataBind();
}
}
Tuesday, 20 February 2018
Difference between Web.config and Machine.config:
Configuration files are used to
control and manage the behavior of a web application.
- Machine.config:This is automatically installed when you install Visual Studio. Net.This is also called machine level configuration file. Only one Machine.config file exists on a server.This file is at the highest level in the configuration hierarchy.
- Web.config:This is automatically created when you create an ASP.Net web application project. This is also called application level configuration file. This file inherits setting from the Machine.config
Difference between Web.config and
Machine.config:
- The settings made in the Web.config file are applied to that particular web application only whereas the settings of Machine.config file are applied to the whole asp.net application.
- Web.config file Setting of asp.net all project Machine.config are setting of server setting and when the web side are implemented time it work all project but Web.config file set all projects
- Web config will be for that particular aplln whereas the Machine .config will for the whole machine
- Every ASP.NET application that you has a Web.config file . The settings specified in this will imply only to that application.Whereas Your System will have a Machine.config file in Microsoft.NET\Framework\v1.1.4322\CONFIG Folder which contains specifications and settings at a system level.
- Web.config file is to override the settings from the Machine.config file. Machine.config file settings are applied to all the webapplications residing on the server while Web.config settings are application specific.
- Machine. config is configuration file for all the application in the IIS. but Web.config is a configuration file for a application or folder.
- Machine.config for machine level configuration. but Web.config for a application/folder level configuration
Tuesday, 13 February 2018
is it possible to run my webpages on live site without web.config..?
Yes you can
Because all the configuration settings will be
available under MACHINE.CONFIG file by default these settings will be applied
to all asp.net applications. The MACHINE.CONFIG file will be automitacally
loaded when .net framework is installed.
it is something like if we had not defined the
web.config the application will take the settings from the
machine.config. the machine.config settings are overide by the web.config
if u define the web.config for each running application.
In 2005 The VS When we trying to run first time any
application the 2005 VS gives us warning that want to run application without web.config
file.
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