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PostgreSQL Functionality (cont)

PostgreSQL's dialect of SQL is mostly standard (but with extensions).

Differences visible at the user-level:

  • attributes containing arrays of atomic values
  • table type inheritance, table-valued functions, ...
Differences at the implementation level:
  • referential integrity checking is accomplished via triggers
  • views are implemented via query re-writing rules
Example: 

create view myview as select * from mytab;
-- is implemented as
create type as myview (same fields as mytab);
create rule myview as on select to myview
            do instead select * from mytab;