|
Can someone tell me what is the difference between these two:
ALTER TABLE x1 ADD INDEX(a); ALTER TABLE x1 ADD INDEX(b);
AND
ALTER TABLE x1 ADD INDEX(a,b);
I know this goes down to the very basics but sometimes I find the former seems to be a little faster...
Started by Legend on
, 4 posts
by 4 people.
Answer Snippets (Read the full thread at stackoverflow):
Source....
It is possible or greater indexed column.
With your second option, the following query will not use the index:
SELECT * FROM x1 WHERE b = 'something';
The order in which columns are listed in the index definition is important.
|
|
Can anyone tell me when an index is a bad index?
Started by Anoop on
, 9 posts
by 9 people.
Answer Snippets (Read the full thread at stackoverflow):
If the index....
The index is to help us to search the rows faster.
In contrary you might suffer performance hit.
If the field is never used, it is a bad index (if you feel unecessary things are bad of performance that indeces are for.
|
|
Echo '<option value='+$index+'>'+$county[$index];
It is PHP code. It doesn't output what I want. Any idea?
Started by Steven on
, 7 posts
by 7 people.
Answer Snippets (Read the full thread at stackoverflow):
$index....
And the .= operators if you want: String Operators
Try this:
echo '<option value=' .
Operator not the +
echo '<option value='.$index.'>'.$county[$index];
You can read more about the .
To concatenate text in PHP use the.
|
Ask your Facebook Friends
|
Please, can anyone explain me what is the difference between Index Rebuilding and Index Reorganizing? Thanks in Advance
Started by Anoop on
, 6 posts
by 6 people.
Answer Snippets (Read the full thread at stackoverflow):
:)
Think about how the index is implemented....
Basically, rebuilding is a total rebuild of an index - it will build a new index, then drop the existing one, whereas reorganising it will simply, well.
There are a number of differences.
|
|
In SQL Server 2005, the query analyzer has told me many times to create a non-clustered index on a primary ID column of a table which already has a clustered index. After following this recommendation, the query execution plan reports that the query should...
Started by Kevin Berridge on
, 4 posts
by 4 people.
Answer Snippets (Read the full thread at stackoverflow):
So if the table already has a clustered index on a different column, then a non-clustered index is the best you if you're just checking if....
A clustered index will generally be faster, but you can only have 1 clustered index.
|
|
I'm new to database indexing, if I have 2 columns in a table that are good choices for indexing like for example,
[Posts]( [PostID] [int] IDENTITY(1,1) NOT NULL, [UserName] [nvarchar](64) NOT NULL, [ApplicationType] [smallint] NOT NULL, ... )
in this ...
Started by ray247 on
, 4 posts
by 4 people.
Answer Snippets (Read the full thread at stackoverflow):
If your searches will nearly always include both columns, then creating an index on both columns to search the phone book for everyone with the first name of Scott, you'd want a new index that wasn't that with the multi-column index....
|
|
I've just been adding an Index to a table in SQL Server 2005 and it got me thinking. What is the difference between creating 1 index and defining multiple columns over having 1 index per column you want to index.
Are there certain reasons why one should...
Started by GateKiller on
, 6 posts
by 6 people.
Answer Snippets (Read the full thread at stackoverflow):
In SQL Server 2005, you can also add additional columns to the index that....
If an index is "covering", then there is no need to use anything but the index.
I recommend you check out Kimberly Tripp's articles on indexing .
|
|
We run full re-indexes every 7 days (i.e. creating the index from scratch) on our Lucene index and incremental indexes every 2 hours or so. Our index has around 700,000 documents and a full index takes around 17 hours (which isn't a problem).
When we ...
Started by Mat Mannion on
, 3 posts
by 3 people.
Answer Snippets (Read the full thread at stackoverflow):
If you're using the....
An optimize operation reads and writes the entire index, which is why it's so IO intensive!
The idea behind optimize operations is to re-combine all the various segments in the Lucene index into one files per query.
|
|
Background: I have a table with 5 million address entries which I'd like to search for different fields (customer name, contact name, zip, city, phone, ...), up to 8 fields. The data is pretty stable, maximum 50 changes a day, so almost only read access...
Started by MicSim on
, 5 posts
by 5 people.
Answer Snippets (Read the full thread at stackoverflow):
For the sake of completeness, the above syntax to search for "contains", a full... .
Field2, field3 FROM table WHERE field1 LIKE '%value%
Then no index will be used anyway when searching on field1 and you have to resort to a full-text index.
|
|
Public ArrayList choiceArray = new ArrayList(); public UC_RadioX Item(int index) { return (UC_RadioX)choiceArray[index]; }
when i used
cc.Item(0).Checked = true; cc.Item(1).Checked = true;
howto change method to propoties
Started by monkey_boys on
, 3 posts
by 3 people.
Answer Snippets (Read the full thread at stackoverflow):
That will allow you to use the [] notation.
Public ArrayList choiceArray = new ArrayList(); public UC_RadioX this[int index] { get { return (UC_RadioX)choiceArray[index]; } } // ...
Way:
// ...
|
