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SQLite UPSERT / UPDATE OR INSERT
... there are two ways to accomplish this, depending on the structure of your table and if you have foreign keys restrictions activated to maintain integrity. I'd like to share this in a clean format to save some time to the people that may be in my situation.
Option 1: You can afford deleting the row...
How do I automatically update a timestamp in PostgreSQL
...
To populate the column during insert, use a DEFAULT value:
CREATE TABLE users (
id serial not null,
firstname varchar(100),
middlename varchar(100),
lastname varchar(100),
email varchar(200),
timestamp timestamp default current_timestamp
)
Note that the value for that column c...
Cost of len() function
... the most common implementation of the Python language. Here's a link to a table that provides the algorithmic complexity of many different functions in CPython:
TimeComplexity Python Wiki Page
share
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What is the difference between tinyint, smallint, mediumint, bigint and int in MySQL?
... take up different amounts of space and they have different ranges of acceptable values.
Here are the sizes and ranges of values for SQL Server, other RDBMSes have similar documentation:
MySQL
Postgres
Oracle (they just have a NUMBER datatype really)
DB2
Turns out they all use the same specific...
How does @synchronized lock/unlock in Objective-C?
...dn't feel like writing section directives in order build the DWARF3 unwind tables ;-)
– Louis Gerbarg
Aug 1 '09 at 1:33
...
Avoid line break between html elements
...
nobr is too unreliable, use tables
<table>
<tr>
<td> something </td>
<td> something </td>
</tr>
</table>
It all goes on the same line, everything is level with eachother,...
MongoDB and “joins” [duplicate]
...r hand will resolve relationships and return them as if they were a single table (you "join two tables into one").
You can read more about DBRef here:
http://docs.mongodb.org/manual/applications/database-references/
There are two possible solutions for resolving references. One is to do it manuall...
How to $http Synchronous call with AngularJS
...model="search"></input>
<div class="bs-example">
<table class="table" >
<thead>
<tr>
<th>#</th>
<th>Description</th>
</tr>
</thead>
<tbody>
...
delete_all vs destroy_all?
I am looking for the best approach to delete records from a table. For instance, I have a user whose user ID is across many tables. I want to delete this user and every record that has his ID in all tables.
...
Awk学习笔记 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...置函数
控制流命令
4. awk的环境变量
Table 1. awk的环境变量
变量
描述
$n
当前记录的第n个字段，字段间由FS分隔。
$0
完整的输入记录。
ARGC
命令行参数的数目。
...