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101) What is filter factor?
one divided by the number of distinct values of a column.
102) What is index cardinality? –
The number of distinct values a column or columns contain.
103) What is a synonym ?
Synonym is an alternate name for a table or view used mainly to hide the
leading qualifier of a table or view.. A synonym is accessible only by the
creator.
104) What is the difference between SYNONYM and ALIAS?
SYNONYM: is dropped when the table or tablespace is dropped. Synonym is
available only to the creator.
ALIAS: is retained even if table or tablespace is dropped. ALIAS can be
created even if the table does not exist. It is used mainly in distributed
environment to hide the location info from programs. Alias is a global object
& is available to all.
105) What do you mean by NOT NULL WITH DEFAULT? When will you use it?
This column cannot have nulls and while insertion, if no value is supplied
then it wil have zeroes, spaces or date/time depending on whether it is numeric,
character or date/time.
Use it when you do not want to have nulls but at the same time cannot give
values all the time you insert this row.
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