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What are the pre requisites ?
I. to modify data type of a column ? ii. to add a column with NOT NULL constraint ? To Modify the datatype of a column the column must be empty. to add a column with NOT NULL constrain, the table must be empty.
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What are the advantages of VIEW ?
To protect some of the columns of a table from other users.To hide complexity of a query.To hide complexity of calculations.
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What is a transaction ?
Transaction is logical unit between two commits and commit and rollback.
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What is an Integrity Constraint ?
Integrity constraint is a rule that restricts values to a column in a table.
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What is a database link ?
Database Link is a named path through which a remote database can be accessed.
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What is the fastest way of accessing a row in a table ?
Using ROWID.CONSTRAINTS
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How to access the current value and next value from a sequence ? Is it possible to access the current value in a session before accessing next value ?
Sequence name CURRVAL, Sequence name NEXTVAL.It is not possible. Only if you access next value in the session, current value can be accessed.
SQL*Plus interview Questions
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