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Are GUID collisions possible?
...ither unique (for things like version 1 GUIDs), or both unique and unpredictable (for things like version 4 GUIDs). SQL Server's implementation for their NEWID() function appears to use a 128-bit random number, so you're not going to get a collision.
For a 1% chance of collision, you'd need to gen...
Check for column name in a SqlDataReader object
...elp anyone setting their debugger to break on exceptions thrown.
GetSchemaTable() is also another suggestion in many answers. This would not be a preffered way of checking for a field's existance as it is not implemented in all versions (it's abstract and throws NotSupportedException in some versio...
How to get record created today by rails activerecord?
...ion suggested in the accepted answer can cause performance issues when the table size grows.
Typically, if you perform lookups based on created_at column, add an index on the table in your migration file.
add_index :posts, :created_at
Now, to lookup records created today:
Rails 3/4
Post.where...
Test for non-zero length string in Bash: [ -n “$var” ] or [ “$var” ]
...on that shows more differences between [ (aka test) and [[.
The following table shows that whether a variable is quoted or not, whether you use single or double brackets and whether the variable contains only a space are the things that affect whether using a test with or without -n/-z is suitable ...
What are the use cases of Graph-based Databases (http://neo4j.org/)? [closed]
...nto the current blub architecture, use a graph database, or CouchDB, or BigTable, or whatever fits your app and you think is cool. It might give you an advantage, and its fun to try new things.
Whatever you chose, try not to build the database engine yourself unless you really like building databas...
SQL Server equivalent to Oracle's CREATE OR REPLACE VIEW
...ISTS' to check if the view exists and drop if it does.
IF EXISTS (SELECT TABLE_NAME FROM INFORMATION_SCHEMA.VIEWS
WHERE TABLE_NAME = 'MyView')
DROP VIEW MyView
GO
CREATE VIEW MyView
AS
....
GO
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Reset the database (purge all), then seed a database
Is there a rake command to wipe out the data in the database tables?
6 Answers
6
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Is the NOLOCK (Sql Server hint) bad practice?
...dated at the same time another process may be selecting data from the same table. If this happens a lot then there's a high probability of deadlocks unless you use a database mode such as READ COMMITED SNAPSHOT.
I have since changed my perspective on the use of NOLOCK after witnessing how it can i...
Detect if value is number in MySQL
...
This should work in most cases.
SELECT * FROM myTable WHERE concat('',col1 * 1) = col1
It doesn't work for non-standard numbers like
1e4
1.2e5
123. (trailing decimal)
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Best way to do nested case statement logic in SQL Server
... NULL
END AS 'calculatedcol1',
col4,
col5 -- etc
FROM table
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