Schema Evolution publication categorizer

We provide a principled extension of SQL, called
SchemaSQL , that offers the capability of uniform
manipulation of data and meta-data in relational
multi-database systems. We develop a
precise syntax and semantics of SchemaSQL in
a manner that extends traditional SQL syntax
and semantics, and demonstrate the following. (1)
SchemaSQL retains the flavour of SQL while supporting
querying of both data and meta-data. (2)
It can be used to represent data in a database
in a structure substantially different from original
database, in which data and meta-data may
be interchanged. (3) It also permits the creation
of views whose schema is dynamically dependent
on the contents of the input instance. (4)
While aggregation in SQL is restricted to values
occurring in one column at a time, SchemaSQL
permits “horizontal” aggregation and even aggregation
over more general “blocks” of information.
(5) SchemaSQL provides a great facility
for interoperability and data/meta-data management
in relational multi-database systems. We
provide many examples to illustrate our claims.
We outline an architecture for the implementation
of SchemaSQL and discuss implementation
algorithms based on available database technology
that allows for powerful integration of SQL based
relational DBMS.