article in Tech
programming
Database info and general stuff. (SQL clients, commands, etc)
In interviews, I like to ask the question: What is a left join, and why would you use it?
This is not an easy question. This is a question that indicates if that candidate understands what the LEFT join is used for, and it is something that is crucial to ensure you get all of the results.
If they answer that, then, it's what is third normal form.
SQL graphics | code.openark.org - coordinate system using SQL. proven, that anything is possible.
SELECT
GROUP_CONCAT(
IF(
ROUND(SQRT(POW(numbers1.value-(@size-1)/2, 2) + POW(numbers2.value-(@size-1)/2, 2))) <= @radius,
'#', '-')
ORDER BY numbers1.value
SEPARATOR ' ') AS circle
FROM
tinyint_asc numbers1,
tinyint_asc numbers2,
(select @size := 15) sel_size,
(select @radius := 6) sel_radius
WHERE
numbers1.value < @size
AND numbers2.value < @size
GROUP BY numbers2.value
;
+-------------------------------+
| circle |
+-------------------------------+
| - - - - - - - - - - - - - - - |
| - - - - - # # # # # - - - - - |
| - - - # # # # # # # # # - - - |
| - - # # # # # # # # # # # - - |
| - - # # # # # # # # # # # - - |
| - # # # # # # # # # # # # # - |
| - # # # # # # # # # # # # # - |
| - # # # # # # # # # # # # # - |
| - # # # # # # # # # # # # # - |
| - # # # # # # # # # # # # # - |
| - - # # # # # # # # # # # - - |
| - - # # # # # # # # # # # - - |
| - - - # # # # # # # # # - - - |
| - - - - - # # # # # - - - - - |
| - - - - - - - - - - - - - - - |
+-------------------------------+
SQL pie chart | code.openark.org - (single query) SQL-generated pie chart. lol!
SQL Fiddle
Coding Horror: A Visual Explanation of SQL Joins
SQuirreL SQL Client is a graphical Java program that will allow you to view the structure of a JDBC compliant database, browse the data in tables, issue SQL commands etc,
SQuirreL SQL Client Home Page
MySQL :: Download Connector/Net 1.0
MySQL :: Download Connector/Net 5.0
US Cities and State SQL Dump - looking for city and state information for the US? This is nice, SQL data right here...
Developing Time-Oriented Database Applications in SQL
Use The Index, Luke!: A Guide To SQL Database Performance
Learn Code The Hard Way -- Books And Courses To Learn To Code
I am a fan of auditing, and many people do not pay enough attention to auditing the changes that occur within their tables. Additionally, performance and backend optimization are often left to languish. Selecting *....
Take a little care, think about the data and the relational model, are you using foreign keys and joining all the time? Is there some other modeling approach you might try...where auditing and joining issues are not of concern? Maybe a NoSQL is something to look at.
non-relational databases (nosql) - Dave Horner's Website
database change management
LiquiBase | Database Refactoring | home - Liquibase is an open source (Apache 2.0 Licensed), database-independent library for tracking, managing and applying database changes.
sqitch - Sane database change management - metacpan.org
Just a Theory - author of sqitch blog David E. Wheeler.
PGCon2013: Agile Database Development - presentation on Git, Sqitch, and pgTAP
DBIx::Changeset - search.cpan.org
roundhouse - RoundhousE - Migrate and Version Your Database - Google Project Hosting
Seven database (PosgreSQL, Riak, Hbase, MongoDB, CouchDB, Neo4J, Re...
Sqlite || embedded SQL
in-process library, self-contained, serverless, zero-configuration, transactional SQL database engine. in public domain!
SQLite Home Page
SQLiteStudio
Created: 2008-04-21 12:30:01
Modified: 2014-05-16 18:58:02
