Cloud computing is not suited for situations where complex legacy systems have to be ported.
A data dictionary is a special file that contains a set of information describing the contents, format, and structure of a database and the relationship between its elements, used to control access to and manipulation of the database.
Can?t delete a row from primary table if there are related rows in secondary table.
A view may be a subset of the database or it may contain virtual data that is derived from the database files but is not explicitly stored .
Database provides necessary means to achieve this abstraction. By structure of a database we mean the data types, relations, and constraints that should hold on the data.
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