Interview Questions

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>

It can be done by setting the record length’s size to more than half of the page’s size.

In a correlated query, the outer query is related to the inner query. This means one or more columns in the outer query are referenced. It’s used when the outer queries value is being used by inner query. For example, we need to find which employee had more perks in the current month than they did in the previous month. The correlated subquery is executed for each row of perks information in the parent query to first determine what the perks were for each employee in the previous month. This data, in turn, is compared to perks for each employee in the current month, and only those employees whose perks in the current month were greater that their previous month's perks are returned.

Syntax:

SORT   file-1 ON ASCENDING/DESCENDING KEY key....

USING  file-2

GIVING file-3.

USING can be substituted by INPUT PROCEDURE IS para-1 THRU para-2

GIVING can be substituted by OUTPUT PROCEDURE IS para-1 THRU para-2.

file-1 is the sort workfile and must be described using SD entry in FILE SECTION.

file-2 is the input file for the SORT and must be described using an FD entry in FILE SECTION and SELECT clause in FILE CONTROL.

file-3 is the outfile from the SORT and must be described using an FD entry in FILE SECTION and SELECT clause in FILE CONTROL.

file-1, file-2 & file-3 should not be opened explicitly.

INPUT PROCEDURE is executed before the sort and records must be RELEASEd to the sort work file from the input procedure.

OUTPUT PROCEDURE is executed after all records have been sorted. Records from the sort work file must be RETURNed one at a time to the output procedure.

There are three ways to integrate CSS into a Web page 

1. Inline: HTML elements may have CSS applied to them via the STYLE attribute.

2. Embedded: By placing the code in a STYLE element within the HEAD element.

3. Linked/ Imported: Place the CSS in an external file and link it via a link element.

Primary key : a relational database constraint. Primary key consists of one or more columns that uniquely identify a row in the table. For a normalized relation, there is one designated primary key.

Unique index: a physical object that stores only unique values. There can be one or more unique indexes on a table.

- A web page with large number of images takes a longer time to load. This is because each image separately sends out a http request.

- The concept of CSS sprite helps in reducing this loading time for a web page by combining various small images into one image. This reduces the numbers of http request and hence the loading time.

Oracle SQL developer is an Oracle Database IDE.