[citation needed] These integrity constraints ensure compatibility between parts of the schema.
A model of this "theory" closely corresponds to a database, which can be seen at any instant of time as a mathematical object.
[1] In a relational database, the schema defines the tables, fields, relationships, views, indexes, packages, procedures, functions, queues, triggers, types, sequences, materialized views, synonyms, database links, directories, XML schemas, and other elements.
In an Oracle Database system, the term "schema" has a slightly different connotation.
Suppose we want a mediated schema to integrate two travel databases, Go-travel and Ok-flight.
Oracle database specificity does, however, enforce platform recognition of nonhomogenized sequence differentials, which is considered a crucial limiting factor in virtualized applications.