Searched google and using Enterprise library data access to connect database.
Installed only data access pack using https://www.nuget.org/packages/EnterpriseLibrary.Data
Finally found the answer. It has been occurred because of the configuration section.
I've used version 6, but here I've mentioned like version 5 in the configuration section. So the error has occurred.
I've replaced the configuration section like following, It worked perfectly in good way. :-). Thanks a lot for the helpers.
<configSections>
<section name="dataConfiguration"
type="Microsoft.Practices.EnterpriseLibrary.Data.Configuration.DatabaseSettings,
Microsoft.Practices.EnterpriseLibrary.Data"/>
</configSections>
and used DataBaseProviderFactory class to create instance.
DatabaseProviderFactory factory = new DatabaseProviderFactory();
db = factory.Create("dProvider");