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What are the main performance differences between varchar and nvarchar SQL Server data types?
...)
size needed for tempdb
performance of triggers (for inserted and deleted tables that are stored in tempdb)
performance of row versioning (if using SNAPSHOT ISOLATION, since the version store is in tempdb)
ability to get new disk space when the CFO says that they just spent $1 million on a SAN last...
When should I use cross apply over inner join?
...readable and probably less efficient.
Update:
Just checked.
master is a table of about 20,000,000 records with a PRIMARY KEY on id.
This query:
WITH q AS
(
SELECT *, ROW_NUMBER() OVER (ORDER BY id) AS rn
FROM master
),
t AS
(
SELEC...
Generate GUID in MySQL for existing Data?
I've just imported a bunch of data to a MySQL table and I have a column "GUID" that I want to basically fill down all existing rows with new and unique random GUID's.
...
Split code over multiple lines in an R script
... the answers above work fine. But if you have a Code such as those in data.table chaining Syntax it becomes abit challenging. e.g. I had a Problem like this.
mass <- files[, Veg:=tstrsplit(files$file, "/")[1:4][[1]]][, Rain:=tstrsplit(files$file, "/")[1:4][[2]]][, Roughness:=tstrsplit(files$file...
Convert objective-c typedef to its string equivalent
...ms are really just glorified integer constants. You'll have to generate a table of names yourself (or with some preprocessor abuse). For example:
// In a header file
typedef enum FormatType {
JSON,
XML,
Atom,
RSS
} FormatType;
extern NSString * const FormatType_toString[];
// In...
Need to list all triggers in SQL Server database with table name and table's schema
I need to list all triggers in SQL Server database with table name and table's schema.
19 Answers
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How to add border radius on table row
...
You can only apply border-radius to td, not tr or table. I've gotten around this for rounded corner tables by using these styles:
table { border-collapse: separate; }
td { border: solid 1px #000; }
tr:first-child td:first-child { border-top-left-radius: 10px; }
tr:first-ch...
Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign
...is raised:
Then within the command window, call GetErrors method on the table getting the error.
For C#, the command would be ? dataTable.GetErrors()
For VB, the command is ? dataTable.GetErrors
This will show you all datarows which have an error. You can get then look at the RowError for each...
How can I check MySQL engine type for a specific table?
My MySQL database contains several tables using different storage engines
(specifically myisam and innodb). How can I find out which tables are
using which engine?
...
Salting Your Password: Best Practices?
... Site-wide random salt is bad, since an attacker can precompute rainbow tables and grab your entire user database. If you don't understand this, please don't write login/security systems :) - you NEED per-user salts.
– snemarch
Mar 23 '09 at 20:52
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