Answer Posted / sa123
For good performance Index is required.
Consider the case of a very large table (20,000,000 rows)
to which new records are added daily (usually about 1,000
of them). Every night, you need to report these additions
on an audit trail. Rather than scan the whole table looking
for changes, you will want to use an index over the
TRANSACTION_DATE column. But the index would need to be
huge. This is a case in which your index is over the entire
table, although you are actually interested only in the
1,000 or so records that were added today. The actual index
is physically many times larger than it needs to be, and it
uses many more disk I/Os to traverse the binary tree to the
leaf data.
| Is This Answer Correct ? | 8 Yes | 2 No |
Post New Answer View All Answers
What is user in sql?
What is the benefit of foreign key?
How delete all records from table in sql?
What is sql exception?
what are string data types? : Sql dba
how to implement one-to-one, one-to-many and many-to-many relationships while designing tables? : Sql dba
Is it important to partition hard disk?
What is int identity in sql?
what are properties of a transaction? : Sql dba
What is execution plan in sql?
Table 1: col1 Timestamp ---------------- 01-mar-2012 11:12:46 Table 2: col2 Timestamp -------------------- 01-mar-2012 11:12:10 01-mar-2012 11:11:23 Write a query to display a row with table2 col2 value less than tabl1 col1 value. Maximum timestamp value previous to table1 col1 value. Display a result as: Col1 col2 ----- ----- 01-mar-2012 11:12:46 01-mar-2012 11:12:10
How do I save a sql query?
What is mdf ldf and ndf?
What does plv msg allows you to do?
How can you maintain the integrity of your database on instances where deleting an element in a table result in the deletion of the element(s) within another table?
