The type or namespace name 'Data' does not consist in the namespace 'Mono'

Here I'm after searching for hours.I want to connect to SqliteDatabase. When I usedthese System.Data and System.Data.Sqlite fillowing errors showed:

 The type or namespace name 'Data' does not consist in the namespace'System'
 The type or namespace name 'Data' does not consist in the namespace 'Mono'

over different forums and also this one. Different People gave different solutions.One also said change the API framwrok from Framewrok2.0subsetto framewrok2.0. I don't know what to do now.I'm a beginner creating my game for the first time. I'm using this version of unity 5.2.2f1(3757309da7e7). So can somebody tell me what should i do now ?