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What is the difference between Scope_Identity(), Identity(), @@Identity, and Ident_Current()?
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The ident_current(name) returns the last identity created for a specific table or view in any session.
The identity() function is not used to get an identity, it's used to create an identity in a select...into query.
The session is the database connection. The scope is the current query or the c...
Select rows which are not present in other table
I've got two postgresql tables:
4 Answers
4
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How to append rows to an R data frame
...O I come with 4 distinct solutions:
rbindlist to the data.frame
Use data.table's fast set operation and couple it with manually doubling the table when needed.
Use RSQLite and append to the table held in memory.
data.frame's own ability to grow and use custom environment (which has reference seman...
Mysql order by specific ID values
...and FIELD function.
See http://lists.mysql.com/mysql/209784
SELECT * FROM table ORDER BY FIELD(ID,1,5,4,3)
It uses Field() function, Which "Returns the index (position) of str in the str1, str2, str3, ... list. Returns 0 if str is not found" according to the documentation. So actually you sort th...
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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How do I modify a MySQL column to allow NULL?
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You want the following:
ALTER TABLE mytable MODIFY mycolumn VARCHAR(255);
Columns are nullable by default. As long as the column is not declared UNIQUE or NOT NULL, there shouldn't be any problems.
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Select values from XML field in SQL Server 2008
...alue('(/person//lastName/node())[1]', 'nvarchar(max)') as LastName
FROM [myTable]
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Most common way of writing a HTML table with vertical headers?
... option isn't quite valid HTML in the sense that all of the rows (TR) in a table should contain an equal number of columns (TD). Your header has 1 while the body has 3. You should use the colspan attribute to fix that.
Reference: "The THEAD, TFOOT, and TBODY sections must contain the same number of...
Rails: How to list database tables/objects using the Rails console?
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You are probably seeking:
ActiveRecord::Base.connection.tables
and
ActiveRecord::Base.connection.columns('projects').map(&:name)
You should probably wrap them in shorter syntax inside your .irbrc.
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Insert Update trigger how to determine if insert or update
I need to write an Insert, Update Trigger on table A which will delete all rows from table B whose one column (say Desc) has values like the value inserted/updated in the table A's column (say Col1). How would I go around writing it so that I can handle both Update and Insert cases. How would I dete...