大约有 7,000 项符合查询结果（耗时：0.0251秒） [XML]
insert a NOT NULL column to an existing table
...crosoft SQL server. If you want to perform the same operation on Oracle or MySQL you need to use semicolon ; like that:
ALTER TABLE MY_TABLE ADD STAGE INT NULL;
UPDATE MY_TABLE SET <a valid not null values for your column>;
ALTER TABLE MY_TABLE ALTER COLUMN STAGE INT NOT NULL;
...
Best way to create custom config options for my Rails app?
...er in config/initializers:
# Rails 2
APP_CONFIG = YAML.load_file("#{RAILS_ROOT}/config/config.yml")[RAILS_ENV]
# Rails 3+
APP_CONFIG = YAML.load_file(Rails.root.join('config/config.yml'))[Rails.env]
If you're using Rails 3, ensure you don't accidentally add a leading slash to your relative confi...
Groovy Shell warning “Could not open/create prefs root node …”
...JDK source code for WindowsPreferences.java. In this class, both nodes userRoot and systemRoot were declared static as in:
/**
* User root node.
*/
static final Preferences userRoot =
new WindowsPreferences(USER_ROOT_NATIVE_HANDLE, WINDOWS_ROOT_PATH);
/**
* System root node.
*/
static fin...
Remove unnecessary svn:mergeinfo properties
...another way to delete all sub tree svn:mergeinfo properties but not at the root folder (this is needed for branching to work properly).
From the root of the project do:
svn propdel svn:mergeinfo -R
svn revert .
svn ci -m "Removed mergeinfo"
...
Fastest way to determine if an integer's square root is an integer
...st way to determine if a long value is a perfect square (i.e. its square root is another integer):
35 Answers
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Should I use != or for not equal in T-SQL?
...ages) and <> (ANSI).
Databases that support both != and <>:
MySQL 5.1: != and <>
PostgreSQL 8.3: != and <>
SQLite: != and <>
Oracle 10g: != and <>
Microsoft SQL Server 2000/2005/2008/2012/2016: != and <>
IBM Informix Dynamic Server 10: != and <>
Int...
Laravel - Eloquent or Fluent random row
...vel 3:
User::order_by(DB::raw('RAND()'))->get();
Check this article on MySQL random rows. Laravel 5.2 supports this, for older version, there is no better solution then using RAW Queries.
edit 1: As mentioned by Double Gras, orderBy() doesn't allow anything else then ASC or DESC since this chang...
Javascript objects: get parent [duplicate]
...t the same problem.
I have a structure like this:
var structure = {
"root":{
"name":"Main Level",
nodes:{
"node1":{
"name":"Node 1"
},
"node2":{
"name":"Node 2"
},
"node3":{
...
Reset AutoIncrement in SQL Server after Delete
...
If you're using MySQL, try this:
ALTER TABLE tablename AUTO_INCREMENT = 1
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How to avoid “Permission denied” when using pip with virtualenv
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Solution:
If you created the virtualenv as root, run the following command:
sudo chown -R your_username:your_username path/to/virtuaelenv/
This will probably fix your problem.
Cheers
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