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Does MySQL ignore null values on unique constraints?
... '1' for key 'x'
INSERT table1 VALUES (NULL);
INSERT table1 VALUES (NULL);
SELECT * FROM table1;
Result:
x
NULL
NULL
1
This is not true for all databases. SQL Server 2005 and older, for example, only allows a single NULL value in a column that has a unique constraint.
...
Linux下部署企业级邮件服务器(postfix + dovecot + extmail) - 开源 & Gith...
...er=extmail password=extmail
default_pass_scheme = CRYPT
password_query = SELECT username AS user,password AS password FROM mailbox WHERE username = '%u'
user_query = SELECT maildir, uidnumber AS uid, gidnumber AS gid FROM mailbox WHERE username = '%u'
启动dovecot
service dovecot start
...
How to store a list in a column of a database table
... the names that you have given to your girl friend id 1 then you can use:
select names from nicknames where id = 1;
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Why doesn't TFS get latest get the latest?
... have made locally.
If you find yourself using "Get Specific Version" and selecting the "force" and "overwrite" options, then it is very likely that you are in the habit of bypassing all of the enforcements that TFS has implemented to keep you from hurting yourself, and you should probably consider...
How can I see all the issues I'm watching on Github?
...m any page by clicking the notification/bell icon on the top left and then selecting "Managed Notification" > "Subscriptions" from the left menu panel.
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How to securely store access token and secret in Android?
...
From your Android Studio's Project pane, select "Project Files" and create a new file named "keystore.properties" in your project's root directory.
Open "keystore.properties" file and save your Access Token and Secret in the file.
Now load the read the Acc...
Mongoose populate after save
... post.populate('group', 'name').populate({
path: 'wallUser',
select: 'name picture'
}, function(err, doc) {
res.json(doc);
});
});
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How to use Elasticsearch with MongoDB?
...ng bumped up when you update.
echo "mongodb-10gen hold" | sudo dpkg --set-selections
Start the MongoDB service.
sudo service mongodb start
Your database files default to /var/lib/mongo and your log files to /var/log/mongo.
Create a database through the mongo shell and push some dummy data int...
How can I make Visual Studio's build be very verbose?
...
In Visual Studio go to your project and right click on it and select properties. In Linker there is a command line option. There you have all the options and you can add your custom ones. Add /VERBOSE and when linking Visual Studio will show a lot more information.
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How can I make Array.Contains case-insensitive on a string array?
...
new[] { "ABC" }.Select(e => e.ToLower()).Contains("abc") // returns true
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