Execution of extended multidatabase SQL

The multidatabase structured query language (MSQL) is an extension of the SQL query language that provides new functions for nonprocedural manipulation of data in different and mutually non-integrated relational databases. The problems introduced by these new functions are discussed, and the semantics of multiple updates, global commitment, and rollback are analyzed. New language constructs are developed to allow declarative specification of multidatabase transactions. The design and implementation of an environment for the execution of extended MSQL queries in a heterogeneous multidatabase environment are also discussed.<
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