Medical records must be kept over an extended period of time, meanwhile computer based medical records are renewed every 5-6 years. Readability of medical records must be assured even though the systems are renewed by different vendors. To achieve this, we proposed a method called DACS, in which a medical record is considered as an aggregation of documents. A Document generated by a system is transformed to a format read by free software such as PDF, which is transferred with the document meta-information and important data written on the XML to the Document Deliverer. It stores these data into the Document Archiver, the Document Sharing Server and the Data Warehouse (DWH). We developed the Matrix View which shows documents in chronological order, and the Tree View showing documents in class tree structure. By this method all the documents can be integrated and be viewed by a single viewer. This helps users figure out patient history and find a document being sought. In addition, documents' data can be shared among systems and analyzed by DWH. Most importantly DACS can assure the lifelong readability of medical records.