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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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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...
Storing JSON in database vs. having a new column for each key
I am implementing the following model for storing user related data in my table - I have 2 columns - uid (primary key) and a meta column which stores other data about the user in JSON format.
...
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
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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...
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,...
Why do people hate SQL cursors so much? [closed]
...I. Cursors are how parts of the RDBMS work under the hood. Often CREATE TABLE and INSERT have SELECT statements, and the implementation is the obvious internal cursor implementation.
Using higher-level "set-based operators" bundles the cursor results into a single result set, meaning less API b...
Why can't C# interfaces contain fields?
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The virtual keyword is implemented in .NET with methods and a so-called v-table, an array of method pointers. The override keyword fills the v-table slot with a different method pointer, overwriting the one produced by the base class. Properties, events and indexers are implemented as methods und...