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What's the difference between NOT EXISTS vs. NOT IN vs. LEFT JOIN WHERE IS NULL?
It seems to me that you can do the same thing in a SQL query using either NOT EXISTS, NOT IN, or LEFT JOIN WHERE IS NULL. For example:
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Check if SQL Connection is Open or Closed
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You should be using SqlConnection.State
e.g,
using System.Data;
if (myConnection != null && myConnection.State == ConnectionState.Closed)
{
// do something
// ...
}
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SQL, Postgres OIDs, What are they and why are they useful?
I am looking at some PostgreSQL table creation and I stumbled upon this:
4 Answers
4
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Entity Framework 4 vs NHibernate [closed]
...apping, better integration with stored procs / database functions / custom SQL / triggers, support for formula properties and so on. IMO it's basically just more mature as an ORM.
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sqlalchemy IS NOT NULL select
How can I add the filter as in SQL to select values that are NOT NULL from a certain column ?
3 Answers
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Using MySQL with Entity Framework [closed]
Can't find anything relevant about Entity Framework/MySQL on Google so I'm hoping someone knows about it.
10 Answers
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How to insert a SQLite record with a datetime set to 'now' in Android application?
...me function using the Java wrapper "ContentValues". Either you can use :
SQLiteDatabase.execSQL so you can enter a raw SQL query.
mDb.execSQL("INSERT INTO "+DATABASE_TABLE+" VALUES (null, datetime()) ");
Or the java date time capabilities :
// set the format to sql date time
SimpleDateFormat ...
Oracle: If Table Exists
...s for an Oracle database, and was hoping Oracle had something similar to MySQL's IF EXISTS construct.
15 Answers
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How do I send a file as an email attachment using Linux command line?
...'ve created a script that runs every night on my Linux server that uses mysqldump to back up each of my MySQL databases to .sql files and packages them together as a compressed .tar file. The next step I want to accomplish is to send that tar file through email to a remote email server for safeke...
SQL ON DELETE CASCADE, Which Way Does the Deletion Occur?
...new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f13444859%2fsql-on-delete-cascade-which-way-does-the-deletion-occur%23new-answer', 'question_page');
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