I have created one custom database and in that i have employee table.So i want to fetch that data using EPIServer so could any one help me?
To retrieve content from episerver database, you can use IContentLoader or IContentRepository.
In Episerver, content can be any class that implements the IContent interface.
In other words, employees should be saved as either episerver pages, episerver blocks or you can create a custom class that implements the IContent interface.
You can find more info on the following links:
If you don't want to use the episerver API, then you can retrieve the content using any .net orm tool such as EntityFramework, Dapper, etc.