Method, apparatus and computer program for migrating records in a database from a source database schema to a target database schema

A system for migrating records in a database from a source database schema to a target database schema, the system comprising:

• a computer with memory and at least one processor;
• a database coupled to the computer;
• a database access tool executing in the memory of the computer and comprising program code enabled upon execution in the memory of the computer to migrate the source database schema to the target database schema by:
• receiving a request to delete a state from the source database schema;
• marking said state as an actionless redundant state indicating said state requested to be deleted;
• identifying a resultant state present in the target database schema to which to migrate database records in the redundant state;
• defining a migration path array having a plurality of attributes including a migration path attribute beginning with the redundant state;
• defining a plurality of variables including a current migration path variable set to the redundant state, a number of migration paths variable identifying a number of rows in the migration path array, a first incomplete migration path variable, a variable listing the resultant state and all other non-actionless states in the target database, and a variable indicating states that do not lead to a valid migration path;
• calculating a valid migration path between the redundant state and the resultant state using the defined variables and defined migration path array by determining whether an action exists in the source schema to advance a record from the redundant state to a first state in a possible migration path;
• and,
• using a valid migration path to migrate database records in the redundant state to the resultant state, in accordance with the target schema, and using the interim schema to permit database records in the redundant state to be moved between the redundant actionless state and the first state.