you can do it using flat files.
To get the file from your system to IS.You can use built in service getFile which is in wmPublic package may be under file folder.
It takes input
1.Filename :- you give the complete path where it is stored.
2.LoadAs :- in format you want to read the file i.e Stream or Bytes it depends on your requirement.
It gives output
1.body(It contains content of u r file)
after that you can pass the Body(content of file)
to the inbuilt flatfile service convertTovalues, which u can find it in wmFlatfile pakage.
it takes input
1.ffData :- file content interms of Bytes or Stream
2.ffSchema :- provide the entire name space of your Schema where it is stored.(I think uhave idea about name space)
it gives the output
1.ffvalues :- this is a documet it contains document list each document in this list represent each record of your file
after u get each record you can store them in database using your appropriate adapter service
For more information about creating flatfile Dictionary and flatFile Schema, storing ffvalues in to database.
Refer webmethods Flatfile Schema Developers Guide under webmethods documentation
If u have any doubts u can post immediately regarding this