Prototype databases are needed in any information system development process to support data-intensive applications development.
It is common practice to populate these databases using synthetic data. This data usually bears little relation to the application's
domain and considers only a very reduced subset of the integrity constraints the database will hold during operation.
This paper claims that in situations where operational data is available, as is the case in information system evolution and
migration, a sample of this data must be used to create a prototype database. The paper outlines a method for consistently
sampling a database. This method uses a new concept, the Insertions Chain Graph, to assist in selecting instances so that
the resulting Sample Database reaches a consistent state, a significant task of database sampling.