返回存储库模式和数据类型

I am using the repository pattern and was wondering about what data type I should return. In my database I have a string that is variable length that needs to be broken up based off of fixed lengths. I was initially thinking of passing out the string and letting the service layer do the parsing based on the lengths of the configured columns. I dont really like the idea of passing a string out of the repository layer, would rather pass out a complete object. Passing out the string seems like not enough separation of responsibility, but having the repository having to go to another method to get how the string should be parsed and doing the parsing seems like too much work for the repo. Any suggestions of what should be the responsibility of the repo and service in this case?I am using the repository pattern and was wonde