One of the most important features of database systems istransaction management. Transaction management ensures concurrency- and recovery control.
In conventional database systems, classical transactionmanagement ensures the ACID properties of transactions whichare of utmost importance to many applications like banking,reservation systems, and bookkeeping. However, there are advanced applications where classicaltransaction management is too restrictive. This is because classical transaction management enforces total isolation amongtransactions, while to some advanced applications it is important to let transactions cooperate by sharing data and do teamwork. Examples of applications for which the classical transaction management is too restricitive are CAD/CAM, publishing, and document handling.
Apotram is an advanced transaction model developed in order tomeet the cooperation requirements of advanced applications. It was first presented in the PhD thesis of Ole Jørgen Anfindsen. Nested databases in Apotram enable transactions to do teamwork, and parameter sets are used to customize the notion of conflict and to communicate information about uncommitted shared data to transactions. In this thesis I have written an introduction to database systems and classical transaction management, a motivation for why classical transaction management sometimes is too restrictive, and a presentation of the advanced transaction model Apotram. This is the necessary background for the parameter set issues that are presented and discussed in the last two chapters of mythesis.