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What are the differences between a clustered and a non-clustered index?
...than a clustered index
Both types of index will improve performance when select data with fields that use the index but will slow down update and insert operations.
Because of the slower insert and update clustered indexes should be set on a field that is normally incremental ie Id or Timestamp.
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add column to mysql table if it does not exist
...rade_database_1_0_to_2_0()
BEGIN
-- rename a table safely
IF NOT EXISTS( (SELECT * FROM information_schema.COLUMNS WHERE TABLE_SCHEMA=DATABASE()
AND TABLE_NAME='my_old_table_name') ) THEN
RENAME TABLE
my_old_table_name TO my_new_table_name,
END IF;
-- add a column safely
IF NO...
View HTTP headers in Google Chrome?
...you don't see any resources - look at tabs area (All | XHR JS and etc) and select All
– Zanshin13
Jan 12 '17 at 10:05
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show 4 more comments...
Jdbctemplate query for string: EmptyResultDataAccessException: Incorrect result size: expected 1, ac
...ce is you call ResultSet.next().
public String test() {
String sql = "select ID_NMB_SRZ from codb_owner.TR_LTM_SLS_RTN "
+ " where id_str_rt = '999' and ID_NMB_SRZ = '60230009999999'";
return jdbc.query(sql, new ResultSetExtractor<String>() {
@Override
...
Selecting pandas column by location
...ed in future versions. See pandas.pydata.org/pandas-docs/dev/… on how to select by position using iloc/iat.
– Wouter Overmeire
Apr 12 '13 at 10:04
1
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Convert Linq Query Result to Dictionary
... @pawan - that doesn't look right. I'd expect var servers = list.Select( s => new { s.ProjectName, Url = "tcp://" + s.BuildMachineName + ":" + s.PortNumber + "/CruiseManager.rem" } ).ToDictionary( s => s.ProjectName, s.Url ); This creates a dictionary keyed by project name of projec...
Visual Studio: How to break on handled exceptions?
...the VS2010 environement, by going to "Tools", "Import Export Settings" and select a reset to the C# environment... it contains the Exceptions Submenu item
– BeardinaSuit
Feb 14 '12 at 16:28
...
How to install Xcode Command Line Tools
...
Xcode 5.1 and OSX 10.9. (also works with Xcode 5.1.1 + OSX 10.10)
xcode-select --install worked with version 2333, failed with version 2003. So, try xcode-select --install and if that does not work download as described below.
In early February 2014 xcode-select --install has been reporting that...
Dynamically select data frame columns using $ and a character value
...and some variable names stored in a character vector cols . When I try to select a variable from mtcars using a dynamic subset of cols , nether of these work
...
How to combine date from one field with time from another field - MS SQL Server
...ro (base date: January 1, 1900)
Adding them returns the correct result.
SELECT Combined = MyDate + MyTime FROM MyTable
Rationale (kudos to ErikE/dnolan)
It works like this due to the way the date is stored as two 4-byte
Integers with the left 4-bytes being the date and the right
4-bytes...