What is a view ?
ORACLE Interview Questions and Answers (Part 4)
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551. What is a view ?
A view is stored procedure based on one or more tables, it’s a virtual table.
552. What is difference between UNIQUE and PRIMARY KEY constraints?
A table can have only one PRIMARY KEY whereas there can be any number of UNIQUE keys. The columns that compose PK are automatically define NOT NULL, whereas a column that compose a UNIQUE is not automatically defined to be mandatory must also specify the column is NOT NULL.
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