Navneet Kumar's Public Library

26 Nov 09

adding LIMIT 1 to your query can increase performance. This way the database
engine will stop scanning for records after it finds just 1, instead of going
thru the whole table or index
The more data is read from the tables, the slower the query will become. It
increases the time it takes for the disk operations. Also when the database
server is separate from the web server, you will have longer network delays due
to the data having to be transferred between the servers
10 more annotations...
- ENUM type columns
  are very fast and compact. Internally they are stored like TINYINT, yet they can
  contain and display string values. This makes them a perfect candidate for
  certain fields
- Unless you have a very specific reason to use a NULL value, you should always
  set your columns as NOT NULL.
- NULL columns require additional space and they can add complexity to your
  comparison statements. Just avoid them when you can.
- "NULL columns require additional space in the row to record whether their values
  are NULL. For MyISAM tables, each NULL column takes one bit extra, rounded up to
  the nearest byte."
- When every single column in a table is "fixed-length", the table is also
  considered "static" or
  "fixed-length". Examples of column types that are NOT fixed-length are:
  VARCHAR, TEXT, BLOB.
- Fixed-length tables can improve performance because it is faster for MySQL
  engine to seek through the records. When it wants to read a specific row in a
  table, it can quickly calculate the position of it. If the row size is not
  fixed, every time it needs to do a seek, it has to consult the primary key
  index.
- You have a "last_login" field in your table. It updates every time a user logs
  in to the website. But every update on a table causes the query cache for that
  table to be flushed. You can put that field into another table to keep updates
  to your users table to a minimum
- When a big query like that is performed, it can lock your tables and bring your
  web application to a halt.
- Apache runs many parallel processes/threads. Therefore it works most efficiently
  when scripts finish executing as soon as possible, so the servers do not
  experience too many open connections and processes at once that consume
  resources, especially the memory.
- If you end up locking your tables for any extended period of time (like 30
  seconds or more), on a high traffic web site, you will cause a process and query
  pileup, which might take a long time to clear or even crash your web server

25 Nov 09

Design Patterns – Strategy Pattern « Cumps.be

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Design-Patterns DesignPatterns OOP Strategy-pattern

CSS Float Theory: Things You Should Know - Smashing Magazine

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CSS Web-Development WebDesign Web Positioning Layout

A floated box is positioned within the normal flow, then taken
out of the flow and shifted to the left or right as far as possible.
“When you float an element it becomes a block box. This box can
then be shifted to the left or right on the current line.
8 more annotations...
- “You should always set a width on floated items
- The first thing we need to remember is that a floating element is shifted either
  to the left or to the right. It is not possible to make an element float in the
  centre
- When we float an element it is shifted to the right or to the left until it
  reaches the edge of the containing block. If we then float another element
  nearby in the same direction, it will be shifted until its edge reaches the edge
  of the first floating element
- “Since a float is not in the flow, non-positioned block boxes created before and
  after the float box flow vertically as if the float didn’t exist
- An inline box is generated by those elements that aren’t block-level
- A line box is an imaginary rectangle that contains all the inline boxes that
  make up a line in the containing block-level element
- If we then want a full-width footer to be shown at the bottom, no matter which
  column happens to be longest, we only need to set clear: both on
  it.”
- rely on browsers to consistently interpret the layout

CSS Layout Or Table Layout | Van SEO Design

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CSS Positioning Layout Web WebDevelopment

Tables by their nature force everything into a box. CSS while also boxlike does
let you break the boundaries of that box and move outside of it
A CSS layout is far easier to maintain than a table layout. Changes generally
need to be made to one external css file to update an entire site.
2 more annotations...
- To change a table layout you will need to change the entire structure of the
  page and the site.
- Browsers need to read all the code of a table before they can display it on a
  monitor. Once to understand the structure of the table and a second time to
  present the information in the table. While the browser is doing that visitors
  to your site see nothing. They get the whole table at once.

The Hardest Thing I Have To Do Every Day (by Jeremy Zawodny)

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Information-Overload Information-Management

The hardest thing I have to do every day is to decide what to ignore
The frustrating thing about all this is that as our electronic tools evolve to
more efficiently find information, I'm a bit more aware every day of how much
stuff I am ignoring. Life was easier when I was ignorant of how much interesting
stuff the world had to offer.

Teach Yourself Programming in Ten Years

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Programming Programmer Learning Career

Coding Horror: Procrastination and the Bikeshed Effect

"There are known knowns. These are things we know that we know. There are known unknowns. That is to say, there are things that we know we don't know. But there are also unknown unknowns. There are things we don't know we don't know."

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CodingHorror Joel Software-Development PeopleManagement Software-Engineering

Although discussion can meander in any topic, the probability of meandering goes
up as the technical difficulty of the topic goes down. After all, the greater
the technical difficulty, the fewer participants can really follow what's going
on
The principle that the amount of discussion is inversely proportional to the
complexity of the topic has been around for a long time, and is known informally
as the Bikeshed Effect.
6 more annotations...
- those who thought about the questions abstractly were much more likely to
  procrastinate -- and in fact some never got around to the assignment at all.
  By contrast, those who were focused on the how, when and where of doing the task
  e-mailed their responses much sooner, suggesting that they hopped right on the
  assignment rather than delaying it
- the amount of discussion on a software feature is inversely proportional to
  its value. Sure, have some initial discussion to figure out your direction,
  but the sooner you can get away from airy abstractions, and down to the nuts and
  bolts of building the damn thing, the better off you
- "There are known knowns. These are things we know that we know. There are known
  unknowns. That is to say, there are things that we know we don't know. But there
  are also unknown unknowns. There are things we don't know we don't know."
- Turns out what we do isn't quite the same, but there was no real way to know
  that without *doing* it.
- Keep in mind, too, that SO has been very, very successful. This is key: the
  methodology under which SO was developed has proven its wisdom. For all we know,
  a similar system planned by a group of "Architecture Astronauts" would still be
  in the conference room hashing out the details of the "User" table
- The task for a project manager in this dilemma is to motivate the team (and
  individuals) on issues they SHOULD think about, but at the same time prevent
  falls into the bikeshed tarpit; the amount of discussion should be proportional
  to value.

Coding Horror: Sharpening the Saw

improving

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Joel Programmer Learning CodingHorror Career

I am too busy sawing to take time to sharpen my saw."
strike a mindful balance between practicing your craft and thinking about how
you practice your craft.
2 more annotations...
- Of course, too much saw sharpening, or random, aimless saw sharpening, can
  become another
  form of procrastination. But a developer who seems completely disinterested
  in it at all is a huge red flag
- People are often successful not despite their dysfunctions but because of them.
  Obsessions are one of the greatest telltale signs of success. Understand
  a person's obsessions and you will understand her natural motivation. The thing
  for which she would walk to the end of the earth.

Coding Horror: Should Competent Programmers be "Mathematically Inclined"?

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Programmer Developer Mathematics

They teach math all wrong in school. Way, WAY wrong. If you teach yourself math
the right way, you'll learn faster, remember it longer, and it'll be much more
valuable to you as a programmer
Nobody knows all of math, not even the best mathematicians. The field is
constantly expanding, as people invent new formalisms to solve their own
problems. And with any given math problem, just like in programming, there's
more than one way to do it. You can pick the one you like best
4 more annotations...
- If math is your preferred way to sharpen your
  saw, then have at it -- but it's hardly the only way.
- younger coders haven't had the pleasure of writing assembler or managing without
  library functions. I've always found strong math skills to be one of the most
  useful skills for coding, and when one has Google and a massive library of
  functions, one
  doesn't have to be good
  at math to get things working, until it either breaks, has edge cases, or brings
  out OS or library bugs.
- What code have you personally written where a detailed knowledge of math made
  your work easier? I can think of some broad categories. Writing a 3D game.
  Or a physics simulation. Or low-level image filters. Or compression algorithms.
  The list goes on and on. But if you're in those situations, you'll know it.
- I think most programmers are smart enough to learn whatever math they need just in time to
  attack the problem at hand.

How to Develop a Mindset for Math | BetterExplained

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Mathematics BetterExplained

24 Nov 09

3 Column CSS Layout | Van SEO Design

3-column layout

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CSS Web-Development WebDesign Web Positioning Layout

The relative positioning actually doesn’t affect the page div at all in how it’s
displayed, but it will become important later when we introduce our new column
to the layout
The margin has been set to 0 however since I used absolute positioning to layout
this column and didn’t need the margin to push the div away from the page div
border.
3 more annotations...
- Now had there been no relative position on the page div the origin would be
  different. Instead of the upper right corner of the page div the origin would
  have been the upper right of the body
- Remember that the origin will be the closest containing div that is also
  positioned. If none of the containing divs have positioning applied the origin
  will ultimately be in the body of the page.
- only trick here was to add relative positioning to the page div, which made
  things easier

2 Column CSS Layout | Van SEO Design

2 column layout with css

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Web WebDesign WebDevelopment CSS Positioning Layout

When something is floated in css it’s taken out of the normal document flow. As
far as the other elements on the page are concerned it’s been removed from the
same document space they occupy and other elements can thus occupy the same
document space
In this layout unless we tell it otherwise the next element on the page (in our
case the content div) will want to sit in the same exact place the menu div sits
3 more annotations...
- The instinct is to use positioning on everything. But there’s a reason why I
  didn’t use it. I want to keep the content div in the normal document flow.
  Keeping it in the normal document flow helps to keep the footer div always
  sitting right below it. Had positioning been used and the content div been
  removed from the document flow as well as the menu then the footer would want to
  occupy the space just below the header.
- adding min-height we can be sure it will never be too short.
- Internet Explorer doesn’t handle the min-height property and so I’ve used
  _height as a sort of min height hack. IE actually interprets _height as height
  and all other browsers ignore it.

Understanding CSS Floats | Van SEO Design

div float positioning 2-column layout

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Web WebDesign WebDevelopment CSS Positioning Rendering Layout

normal flow includes block formatting of block boxes, inline formatting of
inline boxes, relative positioning of block or inline boxes, and positioning of
run-in boxes
In the float model, a box is first laid out according to the normal flow, then
taken out of the flow and shifted to the left or right as far as possible.
Content may flow along the side of a float.
11 more annotations...
- In the absolute positioning model, a box is removed from the normal flow
  entirely (it has no impact on later siblings) and assigned a position with
  respect to a containing block.
- You float an element left or right and allow other elements, usually text to
  flow or wrap around the element. When using floats in this fashion you want to
  have both the floated element and the wrapping text inside the same containing
  element.
- Float both column divs above to the left and you have two columns. You would
  also need to make sure the combined widths of the two column divs can fit inside
  the width of the wrapper div.
- Always set a width on the floated element. Not setting one could have unintended
  consequences.
- If you float two elements left in order to create a two column layout and the
  combined with of the floats is greater than the width of the containing element,
  one of the floated elements will drop to the next line
- The issue is that the header div contains the single floated image and and
  because that image is no longer in the normal document flow, the header div
  considers itself to be empty and has no height.
- Overflow prevents the containing element from collapsing.
- Older versions of IE have a double margin bug. If you float an element in one
  direction and also add a margin on the element in the same direction (left/left
  or right/right), IE doubles the margin
- Floats are laid out in normal document flow and then shifted as far left or
  right within containing elements and removed from normal document flow.
- Elements can flow around floated elements as long as there is enough horizontal
  space to contain them
- Use floats when you want text to flow around an element or to create columns in
  a layout

CSS vs Tables: The Debate That Won’t Die | Van SEO Design

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Web WebDesign CSS HTML

We needed three sets of tags to present some content as opposed to the one set
of div tags.
They impose a more rigid structure than divs. Every table cell is dependent on
the other table cells in its row to maintain the structure
3 more annotations...
- In order for a browser to render a page built with tables it needs to read the
  code on the page twice. Once to understand the structure and another time to
  present it. That extra pass at the code makes table-based layouts take longer to
  display.
- If you find yourself needing hacks then most likely you haven’t thought out your
  structure all that well.
- Divs require less code and are less dependent on each other than tables. That
  leads to easier maintenance, more freedom in design, and quicker load times

How Well Do You Understand CSS Positioning? | Van SEO Design

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CSS Positioning Web

23 Nov 09

Visual jQuery 1.2.6

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JavaScript jQuery API guide

Navneet Kumar's Public Library

Top 20+ MySQL Best Practices - Nettuts+

Design Patterns – Strategy Pattern « Cumps.be

CSS Float Theory: Things You Should Know - Smashing Magazine

CSS Layout Or Table Layout | Van SEO Design

The Hardest Thing I Have To Do Every Day (by Jeremy Zawodny)

Teach Yourself Programming in Ten Years

Coding Horror: Procrastination and the Bikeshed Effect

Coding Horror: Sharpening the Saw

Coding Horror: Should Competent Programmers be "Mathematically Inclined"?

How to Develop a Mindset for Math | BetterExplained

3 Column CSS Layout | Van SEO Design

Visual formatting model

glish.com : CSS layout techniques

Little Boxes

The Layout Reservoir - BlueRobot

2 Column CSS Layout | Van SEO Design

Understanding CSS Floats | Van SEO Design

CSS vs Tables: The Debate That Won’t Die | Van SEO Design

How Well Do You Understand CSS Positioning? | Van SEO Design

Visual jQuery 1.2.6

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