hi
once again iam posting a same query but with a different approach please try to understand and reply me

Iam developing a site like yatra.com now how can i share the databases of all the airlines, hotels etc into my website.that means inorder to maintain a site like yatra.com i could be able to access or share their database how can i achieve this what is the concept behind this please help me thanks in advance

no, you're not going to have access to their systems.
You MAY be allowed access to some public API to query their systems, but that's as far as it goes.
And you'll have to negotiate with each of them separately to get access to those APIs (which may come at a price).

If you don't know that kind of things you're not ready to build something on the scale you seem to envision.

You can also try to crawl their websites, analyze the html that your crawl returns and put it into a database...

But before you do this, make sure you have their approval for this... And again, this approval might come at a price.