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Data structure: insert, remove, contains, get random element, all at O(1)
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Consider a data structure composed of a hashtable H and an array A. The hashtable keys are the elements in the data structure, and the values are their positions in the array.
insert(value): append the value to array and let i be its index in A. Set H[value]=i.
remov...
There can be only one auto column
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My MySQL says "Incorrect table definition; there can be only one auto column and it must be defined as a key" So when I added primary key as below it started working:
CREATE TABLE book (
id INT AUTO_INCREMENT NOT NULL,
accepted_terms BIT(1) NO...
PHP PDO: charset, set names?
...llation by clicking your database and choose operations. If you try create tables with another collation than your database, your tables will end up with the database collation anyways.
So make sure the collation for your database is right before creating tables. Hope this saves someone a few hours...
C++实现一款简单完整的聊天室服务器+客户端 - C/C++ - 清泛网 - 专注C/C++及内核技术
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m_ip.SetAddress(127,0,0,1);
return TRUE; // 除非将焦点设置到控件，否则返回 TRUE
}
void CClientDlg::OnSysCommand(UINT nID, LPARAM lParam)
{
if ((nID & 0xFFF0) == IDM_ABOUTBOX)
{
CAboutDlg dlgAbout;
dlgAbout.DoModal();
}
else
{
CDialog::OnSysCommand(nID, lPar...
How to debug Lock wait timeout exceeded on MySQL?
...the query was attempting to change at least one row in one or more InnoDB tables.
Since you know the query, all the tables being accessed are candidates for being the culprit.
From there, you should be able to run SHOW ENGINE INNODB STATUS\G
You should be able to see the affected table(s)
You get a...
How can I automate the “generate scripts” task in SQL Server Management Studio 2008?
...or the database publishing wizard (sqlpubwiz.exe). It's not currently scriptable from the command line, I might add that contribution in the future.
Scriptio was originally posted on Bill Graziano's blog, but has subsequently been released to CodePlex by Bill and updated by others. Read the discuss...
REST URI convention - Singular or plural name of resource while creating it
...from our database schema. And database standards tend to advocate singular table names, so we're going with that, but still under the same logic as this answer.
– André C. Andersen
Nov 24 '17 at 12:01
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How to create a responsive image that also scales up in Bootstrap 3
...option, here's an alternative solution.
Having a parent div with display: table & table-layout: fixed.
Then setting the image to display: table-cell and max-width to 100%. That way the image will fit to the width of its parent.
Example:
<style>
.wrapper { float: left; clear: left; d...
sqlalchemy unique across multiple columns
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UniqueConstraint or Index constructs explicitly.
As these belong to a Table and not to a mapped Class, one declares those in the table definition, or if using declarative as in the __table_args__:
# version1: table definition
mytable = Table('mytable', meta,
# ...
Column('customer_id',...
Is there a version control system for database structure changes?
...the version (such as removing a column). Each migration is numbered, and a table keeps track of your current db version.
To migrate up, you run a command called "db:migrate" which looks at your version and applies the needed scripts. You can migrate down in a similar way.
The migration scripts the...