SQL Server - using NULLS in your database - Feb 27, 2010 at
11:50 AM by Shuchi Gauri
SQL Server's performance can be affected by using NULLS in your database.
Explain how.
If there is a table having a fixed column length of 255 char, and the user
stores a NULL value in it, the database will still use the 255 char. This
accumulates to a lot of wastage of space which will cause SQL Server to perform
extra I/O operations to read data pages. This wastes space even in data cache
buffer, resulting in poor performance of SQL Server. Thus, it is much more
efficient to store chars like N/A instead of NULL.
SQL Server - using NULLS in your database - May 05, 2009 at
22:00 PM by Rajmeet Ghai
SQL Server's performance can be affected by using NULLS in your database.
Explain how.
NULL values in the database for a column particularly cause problems in
searching and comparison. Query processing for NULL value columns is an
overhead because their values are unknown.
SQL Server - using NULLS in your database - June 21, 2009 at
09:00 AM by Amit Satpute
NULLS that appear in fixed length columns (CHAR) take up the entire size of the
column. This added space increases the size of your database, which in turn
means that it takes more I/O overhead to find the data you are looking for.
Index cannot be used for a query in which the IS NULL clause is used in the
WHERE clause and so the table scans need to be performed which reduces the
performance greatly.
Also read
Null means no entry has been made. It implies that the value is either unknown
or undefined.............
SQL NOT NULL: The NOT NULL constraint enforces a column to NOT accept NULL
values..............
Answer - Stored procedures provide performance benefits through
local storage, precompiling the code, and caching......
Answer - SQL Profiler is a tool that stores
events from the server. SQL Profiler saves the events in the trace file......
Answer - Restricting query result means
return of required rows instead of all rows of the table. This helps in
reducing network traffic......
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