Technology Questions

UNION selects only distinct values whereas UNION ALL selects all values and not just distinct ones

Validation controls are responsible to validate the data of an input control. Whenever you provide any input to an application, it performs the validation and displays an error message to user, in case the validation fails.

ASP.NET 4.0 contains the following six types of validation controls:

   => CompareValidator - Performs a comparison between the values contained in two controls.
   => CustomValidator - Writes your own method to perform extra validation.
   => RangeValidator- Checks value according to the range of value.
   => RegularExpressionValidator - Ensures that input is according to the specified pattern or not.
   =>  RequiredFieldValidator - Checks either a control is empty or not.
   => ValidationSummary - Displays a summary of all validation error in a central location.

Canvas is an element that is used for the graphics for the web page. It uses JavaScript to bring the graphics functionality live. It allows easy way to draw the graphics and use different types of tools to create drawing on the web page. Canvas is just a rectangular area that controls the pixel of every element that is used in the web page. Canvas uses methods like paths, circles, etc. The canvas element will be used as follows:

<canvas id="can" width="200" height="100"></canvas>

The canvas element includes id, width and height settings and with the javascript it gets used like:

<script type="text/javascript">

var c=document.getElementById("can");

var ctx=c.getContext("2d");

ctx.fillStyle="#FF0000";

ctx.fillRect(0,0,150,75);

</script>

A network in which there are multiple network links between computers to provide multiple paths for data to travel.

We can tune the report by using index awarness in universe

I/O operations like reading or writing a file is not possible with client-side javascript. However , this can be done by coding a Java applet that reads files for the script. 

GROUP BY partitions the selected rows on the distinct values of the column on which you group by. HAVING selects GROUPs which match the criteria specified