BD Conf: Visit speed - Page speed is only the beginningPeter McLachlan
How can we beat the speed of light and make visits faster? Pre-fetching is one way we can make resources available before they're needed. This talk explores challenges in mobile visit performance and discusses the design of a generic pre-fetching system.
NewBCamp08 was a first-time unconference for web newbies. There were "tracks" for web development, social media, etc. For more info: newbcamp.com
This presentation addresses: What are web standards? Why use them? Why haven't we been using them all along? What are Microformats? How can you use the URL as a UI?
Can be used as a introductory presentation to web security basics. Contains intro on Attacks to Preventions Tips, organized neatly.
http://codeinmybug.wordpress.com/2007/10/12/the-web-is-broken/
Library Program Technology in Ukraine & RomaniaMark Belinsky
Digital Democracy spent 2 days in Kiev working with IREXʼs library Programs from Ukraine and Romania. The focus of the trainings was to have hands on workshops where trainees would sign up for, install and learn about technology tools that could benefit the library Programs in those countries. Through interactive exercises trainees would come away with tangible experience and an open online conversation about library tech upon which to build in the future through social media.
How to optimize and speed-up your website. The complete guide.Adam Mucha
We believe that in world of web design speed is strength. Faster the website is the better the overall user experience.
Here is the guide for optimizing your website prepared by FROGRIOT digital studio. Years of experience in single presentation. Enjoy it!
Voices that matter: High Performance Web SitesStoyan Stefanov
http://webdesign2010.crowdvine.com/talks/10509
No one likes slow pages. Faster sites increase user satisfaction and happiness, help improve business metrics and, since April 2010, rank higher in Google search results. In this session Stoyan shares his research and expertise covering:
- The performance Golden Rule, which helps you cut page loading time in half.
- Speeding up the initial page rendering.
- Writing smarter CSS.
- Image optimizations that shave 10-30% off the file sizes, with no quality loss.
- Improving the perception of speed
- Maintaining the user's "flow" as they move from page to page
Step ahead of your competitors by building faster and more pleasant user experiences following the proven best practices
BD Conf: Visit speed - Page speed is only the beginningPeter McLachlan
How can we beat the speed of light and make visits faster? Pre-fetching is one way we can make resources available before they're needed. This talk explores challenges in mobile visit performance and discusses the design of a generic pre-fetching system.
NewBCamp08 was a first-time unconference for web newbies. There were "tracks" for web development, social media, etc. For more info: newbcamp.com
This presentation addresses: What are web standards? Why use them? Why haven't we been using them all along? What are Microformats? How can you use the URL as a UI?
Can be used as a introductory presentation to web security basics. Contains intro on Attacks to Preventions Tips, organized neatly.
http://codeinmybug.wordpress.com/2007/10/12/the-web-is-broken/
Library Program Technology in Ukraine & RomaniaMark Belinsky
Digital Democracy spent 2 days in Kiev working with IREXʼs library Programs from Ukraine and Romania. The focus of the trainings was to have hands on workshops where trainees would sign up for, install and learn about technology tools that could benefit the library Programs in those countries. Through interactive exercises trainees would come away with tangible experience and an open online conversation about library tech upon which to build in the future through social media.
How to optimize and speed-up your website. The complete guide.Adam Mucha
We believe that in world of web design speed is strength. Faster the website is the better the overall user experience.
Here is the guide for optimizing your website prepared by FROGRIOT digital studio. Years of experience in single presentation. Enjoy it!
Voices that matter: High Performance Web SitesStoyan Stefanov
http://webdesign2010.crowdvine.com/talks/10509
No one likes slow pages. Faster sites increase user satisfaction and happiness, help improve business metrics and, since April 2010, rank higher in Google search results. In this session Stoyan shares his research and expertise covering:
- The performance Golden Rule, which helps you cut page loading time in half.
- Speeding up the initial page rendering.
- Writing smarter CSS.
- Image optimizations that shave 10-30% off the file sizes, with no quality loss.
- Improving the perception of speed
- Maintaining the user's "flow" as they move from page to page
Step ahead of your competitors by building faster and more pleasant user experiences following the proven best practices
Ngôn ngữ lập trình PHP và MySQL - khoahoclaptrinhweb.tin.vnTrình Kim Ngân
lập trình php, học php, khoá học php, khoá học lập trình với php, khoá học lập trình web với php, lap trinh php, hoc php, khoa hoc php, khoa hoc lap trinh voi php, khoa hoc lap trinh web voi php, tự học lập trình PHP, tu hoc php
Php module 4 - ttth dh khtn [khoahoclaptrinhweb.tin.vn]Trình Kim Ngân
học php, hoc php, khoá học php, khoa hoc php, lập trình php, lap trinh php, tự hoc php, tu hoc php, khoá học lập trình php tại hcm, khoa hoc php tai hcm
Php module 3 - ttth dh khtn [khoahoclaptrinhweb.tin.vn]Trình Kim Ngân
học php, hoc php, khoá học php, khoa hoc php, lập trình php, lap trinh php, tự hoc php, tu hoc php, khoá học lập trình php tại hcm, khoa hoc php tai hcm
Php module 1 - ttth dh khtn [khoahoclaptrinhweb.tin.vn]Trình Kim Ngân
lap trinh php, hoc lap trinh php, hoc php, lập trình php, học lập trình php, học php, khoa hoc php tai hcm, khoá học lập trình php tại hcm, tự học php, tu hoc php, tự học php cơ bản, tu hoc php co ban
Web is now visible everywhere. It's highest time to learn webdevelopment! Know why it's great branch of IT, what it's made of and what tasks are waiting the for today's web developers.
Learn the HTML, JS and CSS from basics. Do not read HTML courses written 10 years ago.
Want to do backend, but still wondering whether to choose PHP, Ruby, Python, nodeJS ? No fear! We'll try to show pros & cons of every language AND also give a short guide how to learn them quickly.
Original presentation: http://akai.org.pl/slides/webstarter/
How Open Source / Open Technology Could Help On Your ProjectWan Leung Wong
ITFest 2014, Seminar on Free & OSS in HK
How Open Source / Open Technology Could Help On Your Project?
A talk brief to talk about how to use open source or open technology to help on start a new project. How to choose technology, and what should people to concern on.
Systems Monitoring with Prometheus (Devops Ireland April 2015)Brian Brazil
Monitoring means many things to many people. This talk looks at Systems Monitoring, that is how to keep an eye on a given system and use this as part of overall management of a system. This talk will cover Why one monitors, What to monitor, How to monitor, the general design of a monitoring system and how Prometheus is a good fit for this in terms of instrumentation, consoles, alerts, general system health and sanity.
Prometheus is a next-generation monitoring system publicly announced earlier this year, developed by companies including SoundCloud, locals Boxever and Docker. Since launch there has been wide-spread interest, and many community contributions.
For more information see http://prometheus.io or http://www.boxever.com/tag/monitoring
محاور :
1- المقدمة
2- مفهوم الدريم ويفر
3- التعرف على طريقة فتح البرنامج
4- التعرف على الادوات المستخدمة في البرنامج
5- معرفة المتطلبات الاساسية لتشغيل البرنامج
6- كيفية تنصيب البرنامج
7- تشغيل البرنامج
8- كيفية اختيار طريقة عرض مساحة العمل
9- التعرف على قوائم البرنامج
10- التعرف على مكونات شاشة البرنامج
11- التعرف على نوافذ البرنامج
12- كيفية تغيير حجم نافذة البرنامج
13- كيفية ضبط اعدادات شريط الحالة
14- كيفية تحديد النوافذ المفضلة
15- تحديد خطوات انشاء موقع بالدريم ويفر
المقدمة:
أدوبي الشركة العملاقة التي قامت بإطلاق العديد من البرامج المتميزة والتي كان لها أثر كبير في مساعدة الناس في مختلف المجالات على إنجاز أعمالهم بسرعةٍ ودقةٍ كبيرةٍ. وهذه البرامج منها من ما تشمل المونتاج والصوتيات ومنها من تشمل تحرير الصور والتعديل عليها. ليس هذا فقط بل كان للمبرمجين أيضاً نصيب من برامجِ أدوبي المميزة، فأطلقت الشركة ادوبي دريم ويفر لمساعدة المبرمجين في كتابة أكوادهم بسهولة. وإذا كنت من المهتمين بـ تعلم Dreamweaver فهذه المحاضرة لك.
قامت شركة أدوبي خلال السنوات المنصرمة بإطلاق العديد من البرامج المتميزة والتي كان لها كبير الأثر في مساعدة الناس من مختلف المجالات على إنجاز أعمالهم بسرعةٍ ودقةٍ كبيرةٍ. فتضمن قائمة البرامج تلك التي تشمل المونتاج والصوتيات وتحرير الصور والتعديل عليها. ليس هذا فقط بل كان للمبرمجين أيضًا نصيبٌ من برامجِ أدوبي المميزة، فأطلقت الشركة ادوبي دريم ويفر لمساعدة المبرمجين في كتابة أكوادهم. فما هو ادوبي دريم ويفر وما استخداماته ومميزاته التي عملت أدوبي على تطويرها.
'أدوبي دريمويفر (بالإنجليزية: Adobe Dreamweaver)، برنامج تطوير ويب. طورت شركة ماكروميديا هذا البرنامج وأطلقته عام 1997، ثم وفي عام 2005 اشترت شركة أدوبي شركة ماكروميديا وشملت العقد الحصول أيضًا على حقوق دريم ويفر، وواصلت بعدها Adobe تطوير ادوبي دريم ويفر حتى أصبح منافسًا قويًا للعديد من البرامج وأدوات تطوير المواقع.
و هو برنامج متخصص لإنشاء وإدارة تطبيقات ومواقع الويب والتعامل معها .. ويسمح لنا هذا البرنامج بإنشاء مواقع وتطبيقات ويب قوية جداً باستخدام أي من اللغات الشهيرة المتاحة حالياً مثل ASP و ASP .net و PHP بالإضافة إلى العديد من اللغات الأخرى .. كما يقدم البرنامج مجموعة متقدمة من الأدوات التي تساعدك على الارتقاء بمستوى خبرتك في تصميم مواقع الإنترنت .. حيث يمكننا من إضافة الخواص التفاعلية Interactivity .. وعمل التحريك Animation للعناصر لإنتاج صفحات ومواقع إنترنت متميزة . والإتقان التام لكيفية إنشاء وتعديل وإدارة مواقع وصفحات الويب
برنامج أدوبي دريمويفر الأول في تصميم المواقع و تطوير صفحات الويب بإصداره الجديد، يمكنك تصميم موقعك و تطويره و تعديل صفحاته بكل سهولة و يعتبر أدوبي دريم ويفر البرنامج الوحيد الذي تستطيع من خلاله الوصول إلى القمة في تصاميمك للمواقع لتكن متناسبة مع جودة الويب 2، بحيث تستطيع تحرير صفحات PHP و HTML و أيضا تحويل ستايل موقعك ليعمل على أكواد CSS و غير ذلك من التطبيقات التي تهم مطوري الويب و أصحاب المواقع، يمكنك برمجة موقعك من الصفر من خلال البرنامج! فهو يتيح لك الكثير من الادوات الخاصة ببرمجة المواقع بعدة لغات مثل البي اتش بي و الهتمل و الجافا سكربت، يمكنك تحميل نسختك المجانية من برنامج أدوبي دريمويفر لتصميم و برمجة المواقع بآخر إصدار مع إدراج العديد من التحسينات الجديدة ليصبح برنامج أدوبي دريمويفر أكثر استقرارا
و مرونة في تص
أ.م.عبدالجبار حسين الظفري
Up and Running with WordPress - Site Shack Nashville Web DesignJudy Wilson
A simple slideshow that provides a brief look at the WordPress backstory + additional information and recommended sources for themes, security measures, hosts and more.
Responsive is the new buzzword!
The main idea here is to:
* kill the buzzword, and replace it with some accurate truth
* and talk about the very difficult industrialization of the wireframing process, and some ideas for solutions to it (experimental part!)
These slides were used to teach the module "Introduction to Enterprise Applications and Tools" for the 3rd year undergraduates of the Department of Computer Engineering, University of Peradeniya in 2010.
Ngôn ngữ lập trình PHP và MySQL - khoahoclaptrinhweb.tin.vnTrình Kim Ngân
lập trình php, học php, khoá học php, khoá học lập trình với php, khoá học lập trình web với php, lap trinh php, hoc php, khoa hoc php, khoa hoc lap trinh voi php, khoa hoc lap trinh web voi php, tự học lập trình PHP, tu hoc php
Php module 4 - ttth dh khtn [khoahoclaptrinhweb.tin.vn]Trình Kim Ngân
học php, hoc php, khoá học php, khoa hoc php, lập trình php, lap trinh php, tự hoc php, tu hoc php, khoá học lập trình php tại hcm, khoa hoc php tai hcm
Php module 3 - ttth dh khtn [khoahoclaptrinhweb.tin.vn]Trình Kim Ngân
học php, hoc php, khoá học php, khoa hoc php, lập trình php, lap trinh php, tự hoc php, tu hoc php, khoá học lập trình php tại hcm, khoa hoc php tai hcm
Php module 1 - ttth dh khtn [khoahoclaptrinhweb.tin.vn]Trình Kim Ngân
lap trinh php, hoc lap trinh php, hoc php, lập trình php, học lập trình php, học php, khoa hoc php tai hcm, khoá học lập trình php tại hcm, tự học php, tu hoc php, tự học php cơ bản, tu hoc php co ban
Web is now visible everywhere. It's highest time to learn webdevelopment! Know why it's great branch of IT, what it's made of and what tasks are waiting the for today's web developers.
Learn the HTML, JS and CSS from basics. Do not read HTML courses written 10 years ago.
Want to do backend, but still wondering whether to choose PHP, Ruby, Python, nodeJS ? No fear! We'll try to show pros & cons of every language AND also give a short guide how to learn them quickly.
Original presentation: http://akai.org.pl/slides/webstarter/
How Open Source / Open Technology Could Help On Your ProjectWan Leung Wong
ITFest 2014, Seminar on Free & OSS in HK
How Open Source / Open Technology Could Help On Your Project?
A talk brief to talk about how to use open source or open technology to help on start a new project. How to choose technology, and what should people to concern on.
Systems Monitoring with Prometheus (Devops Ireland April 2015)Brian Brazil
Monitoring means many things to many people. This talk looks at Systems Monitoring, that is how to keep an eye on a given system and use this as part of overall management of a system. This talk will cover Why one monitors, What to monitor, How to monitor, the general design of a monitoring system and how Prometheus is a good fit for this in terms of instrumentation, consoles, alerts, general system health and sanity.
Prometheus is a next-generation monitoring system publicly announced earlier this year, developed by companies including SoundCloud, locals Boxever and Docker. Since launch there has been wide-spread interest, and many community contributions.
For more information see http://prometheus.io or http://www.boxever.com/tag/monitoring
محاور :
1- المقدمة
2- مفهوم الدريم ويفر
3- التعرف على طريقة فتح البرنامج
4- التعرف على الادوات المستخدمة في البرنامج
5- معرفة المتطلبات الاساسية لتشغيل البرنامج
6- كيفية تنصيب البرنامج
7- تشغيل البرنامج
8- كيفية اختيار طريقة عرض مساحة العمل
9- التعرف على قوائم البرنامج
10- التعرف على مكونات شاشة البرنامج
11- التعرف على نوافذ البرنامج
12- كيفية تغيير حجم نافذة البرنامج
13- كيفية ضبط اعدادات شريط الحالة
14- كيفية تحديد النوافذ المفضلة
15- تحديد خطوات انشاء موقع بالدريم ويفر
المقدمة:
أدوبي الشركة العملاقة التي قامت بإطلاق العديد من البرامج المتميزة والتي كان لها أثر كبير في مساعدة الناس في مختلف المجالات على إنجاز أعمالهم بسرعةٍ ودقةٍ كبيرةٍ. وهذه البرامج منها من ما تشمل المونتاج والصوتيات ومنها من تشمل تحرير الصور والتعديل عليها. ليس هذا فقط بل كان للمبرمجين أيضاً نصيب من برامجِ أدوبي المميزة، فأطلقت الشركة ادوبي دريم ويفر لمساعدة المبرمجين في كتابة أكوادهم بسهولة. وإذا كنت من المهتمين بـ تعلم Dreamweaver فهذه المحاضرة لك.
قامت شركة أدوبي خلال السنوات المنصرمة بإطلاق العديد من البرامج المتميزة والتي كان لها كبير الأثر في مساعدة الناس من مختلف المجالات على إنجاز أعمالهم بسرعةٍ ودقةٍ كبيرةٍ. فتضمن قائمة البرامج تلك التي تشمل المونتاج والصوتيات وتحرير الصور والتعديل عليها. ليس هذا فقط بل كان للمبرمجين أيضًا نصيبٌ من برامجِ أدوبي المميزة، فأطلقت الشركة ادوبي دريم ويفر لمساعدة المبرمجين في كتابة أكوادهم. فما هو ادوبي دريم ويفر وما استخداماته ومميزاته التي عملت أدوبي على تطويرها.
'أدوبي دريمويفر (بالإنجليزية: Adobe Dreamweaver)، برنامج تطوير ويب. طورت شركة ماكروميديا هذا البرنامج وأطلقته عام 1997، ثم وفي عام 2005 اشترت شركة أدوبي شركة ماكروميديا وشملت العقد الحصول أيضًا على حقوق دريم ويفر، وواصلت بعدها Adobe تطوير ادوبي دريم ويفر حتى أصبح منافسًا قويًا للعديد من البرامج وأدوات تطوير المواقع.
و هو برنامج متخصص لإنشاء وإدارة تطبيقات ومواقع الويب والتعامل معها .. ويسمح لنا هذا البرنامج بإنشاء مواقع وتطبيقات ويب قوية جداً باستخدام أي من اللغات الشهيرة المتاحة حالياً مثل ASP و ASP .net و PHP بالإضافة إلى العديد من اللغات الأخرى .. كما يقدم البرنامج مجموعة متقدمة من الأدوات التي تساعدك على الارتقاء بمستوى خبرتك في تصميم مواقع الإنترنت .. حيث يمكننا من إضافة الخواص التفاعلية Interactivity .. وعمل التحريك Animation للعناصر لإنتاج صفحات ومواقع إنترنت متميزة . والإتقان التام لكيفية إنشاء وتعديل وإدارة مواقع وصفحات الويب
برنامج أدوبي دريمويفر الأول في تصميم المواقع و تطوير صفحات الويب بإصداره الجديد، يمكنك تصميم موقعك و تطويره و تعديل صفحاته بكل سهولة و يعتبر أدوبي دريم ويفر البرنامج الوحيد الذي تستطيع من خلاله الوصول إلى القمة في تصاميمك للمواقع لتكن متناسبة مع جودة الويب 2، بحيث تستطيع تحرير صفحات PHP و HTML و أيضا تحويل ستايل موقعك ليعمل على أكواد CSS و غير ذلك من التطبيقات التي تهم مطوري الويب و أصحاب المواقع، يمكنك برمجة موقعك من الصفر من خلال البرنامج! فهو يتيح لك الكثير من الادوات الخاصة ببرمجة المواقع بعدة لغات مثل البي اتش بي و الهتمل و الجافا سكربت، يمكنك تحميل نسختك المجانية من برنامج أدوبي دريمويفر لتصميم و برمجة المواقع بآخر إصدار مع إدراج العديد من التحسينات الجديدة ليصبح برنامج أدوبي دريمويفر أكثر استقرارا
و مرونة في تص
أ.م.عبدالجبار حسين الظفري
Up and Running with WordPress - Site Shack Nashville Web DesignJudy Wilson
A simple slideshow that provides a brief look at the WordPress backstory + additional information and recommended sources for themes, security measures, hosts and more.
Responsive is the new buzzword!
The main idea here is to:
* kill the buzzword, and replace it with some accurate truth
* and talk about the very difficult industrialization of the wireframing process, and some ideas for solutions to it (experimental part!)
These slides were used to teach the module "Introduction to Enterprise Applications and Tools" for the 3rd year undergraduates of the Department of Computer Engineering, University of Peradeniya in 2010.
Rails is not enough, by Javier Ramirez, at Conferencia Rails 2010 in Madrid, ...javier ramirez
We rails people tend to think of Rails as the center-piece of web development. The same thing can be said of .net, Spring/Java Server Faces, Drupal, Python or name-your-web-framework-of-choice-here people.
Web frameworks are just a component of web applications, and if you want to succeed you better know the miriads of other components beyond your rockstar code.
In my session I will talk about things you must take into account and tools/techniques you should master if you want to make a difference in web development, independently of your development language/framework.
Talk delivered at conferencia rails 2010 in Madrid, Spain.
mLearnCon 2014 - A responsive web solution for a complex online educational p...Amy Som
Describes options for mobile learning delivery and responsive web design, and describes the solution undertaken by the University of Arizona Center for Integrative Medicine
Normal Labour/ Stages of Labour/ Mechanism of LabourWasim Ak
Normal labor is also termed spontaneous labor, defined as the natural physiological process through which the fetus, placenta, and membranes are expelled from the uterus through the birth canal at term (37 to 42 weeks
Thinking of getting a dog? Be aware that breeds like Pit Bulls, Rottweilers, and German Shepherds can be loyal and dangerous. Proper training and socialization are crucial to preventing aggressive behaviors. Ensure safety by understanding their needs and always supervising interactions. Stay safe, and enjoy your furry friends!
A workshop hosted by the South African Journal of Science aimed at postgraduate students and early career researchers with little or no experience in writing and publishing journal articles.
Executive Directors Chat Leveraging AI for Diversity, Equity, and InclusionTechSoup
Let’s explore the intersection of technology and equity in the final session of our DEI series. Discover how AI tools, like ChatGPT, can be used to support and enhance your nonprofit's DEI initiatives. Participants will gain insights into practical AI applications and get tips for leveraging technology to advance their DEI goals.
it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
This presentation includes basic of PCOS their pathology and treatment and also Ayurveda correlation of PCOS and Ayurvedic line of treatment mentioned in classics.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
How to Build a Module in Odoo 17 Using the Scaffold MethodCeline George
Odoo provides an option for creating a module by using a single line command. By using this command the user can make a whole structure of a module. It is very easy for a beginner to make a module. There is no need to make each file manually. This slide will show how to create a module using the scaffold method.
45. Tröôùc khi chuùng ta taïo caùc table trong CSDL cuûa MySQL, coù moät vaøi thöù baïn caàn phaûi hieåu
roõ. Nhöõng khaùi nieäm cô baûn maø toâi saép giôùi thieäu sau ñaây raát quan troïng. Baïn haõy chaéc raèng
mình ñaõ naém kyõ veà chuùng tröôùc khi thöïc hieän vieäc thieát keá döõ lieäu.
Null
Vieäc ñaàu tieân baïn phaûi laøm trong vieäc thieát keá moät table laø quyeát ñònh xem moät field coù cho
pheùp giaù trò NULL hay khoâng.
Trong CSDL quan heä, giaù trò NULL cuûa moät field ñoàng nghóa vôùi noù coù theå chaáp nhaän khoâng
coù döõ lieäu trong ñoù. Neân nhôù raèng giaù trò NULL khaùc vôùi giaù trò cuûa moät chuoãi khoâng coù kyù
töï trong ñoù hoaëc soá coù giaù trò 0.
Ñoâi khi trong chöông trình, baïn seõ thöïc hieän moät soá ñoäng taùc so saùnh xem moät chuoãi naøo ñoù
coù chöùa giaù trò hay khoâng, noù coù theå laø moät caâu leänh IF. Xeùt moät ví duï PHP nhö sau:
$var //this is a variable used in the test
if ($var == “”)
{
echo “Var is an empty string”;
} else {
echo $var;
}
46. Neáu baïn thöïc hieän vieäc so saùnh xem giaù trò soá coù phaûi 0 hay khoâng thì cuõng thöïc hieän töông
töï.
Ñoäng taùc so saùnh treân seõ khoâng laøm vieäc ñöôïc ñoái vôùi giaù trò NULL. Baïn neân hieåu raèng
NULL laø khoâng chöùa baát kyø giaù trò gì trong ñoù, cho neân vieäc so saùnh trò khoâng mang yù nghóa
gì caû. Trong chöông 3 baïn seõ thaáy raèng ñoái vôùi giaù trò NULL ñoøi hoûi laäp trình vieân phaûi raát
caân nhaéc khi vieát leänh lieân keát table.
Trong leänh SELECT cuûa SQL, coù moät soá caùch ñeå baïn coù theå kieåm tra neáu nhö moät field
chöùa giaù trò NULL. Tröôùc heát baïn haõy söû duïng haøm Isnull(). Giaû söû tìm moät record trong
table maø giaù trò midle_name laø NULL, baïn coù theå söû duïng query sau:
select * from names where isnull(middle_name);
Hoaëc laáy caùc record maø middle_name khaùc NULL:
select * from names where !isnull(middle_name);
Baïn cuõng coù theå söû duïng is null vaø is not null:
select * from users were addr2 is null;
select * from users where addr2 is not null;
Ñeå roõ hôn, baïn haõy xem chuyeän gì xaûy ra khi toâi coá gaéng lieân keát hai table sau:
47. Khach_hang
ten ho_lot ba_xa
Trung Le Anh 1321
Khai Tong Phuoc Null
Hon_nhan
ba_xa ten ho_lot
1321 Diem Nguyen Thuy
Neáu baïn muoán tìm teân caùc khaùch haøng vaø teân nhöõng baø xaõ cuûa hoï, baïn seõ phaûi lieân keát 2
table naøy thoâng qua field ba_xa. (Xin baïn chôù lo laéng khi chöa hieåu veà cuù phaùp, baïn seõ hoïc
ngay ôû phaàn tieáp theo thoâi).
SELECT * FROM khach_hang, hon_nhan
WHERE khach_hang.ba_xa = hon_nhan.ba_xa
48. Vieäc thöïc hieän naøy chæ ñuùng ñoái vôùi Trung, nhöng seõ coù vaán ñeà ñoái vôùi Khai bôûi vì anh ta haõy
coøn ñoäc thaân vaø ba_xa cuûa anh ta laø NULL.
Trong chöông 3 baïn seõ khaûo saùt kyõ hôn veà vaán ñeà naøy.
Index
Ngöôøi ta noùi raèng öu ñieåm vöôït troäi cuûa Heä quaûn trò CSDL quan heä laø noù thöïc hieän caùc vieäc
tìm kieám hay saép xeáp nhöõng khoái löôïng döõ lieäu khoång loà moät caùch raát nhanh choùng. Sôû dó noù
thöïc hieän ñöôïc vieäc naøy laø do noù coù chöùa moät cô caáu löu tröõ döõ lieäu goïi laø INDEX.
INDEX cho pheùp database server taïo ñöôïc moät field ñaëc tröng tìm kieám vôùi toác ñoä khoù ngôø.
Caùc INDEX ñaëc bieät hoã trôï moät hoaëc moät nhoùm caùc record trong moät table chöùa soá löôïng lôùn
caùc record. Chuùng cuõng hoã trôï toác ñoä cho caùc haøm lieân keát hoaëc taùch nhoùm döõ lieäu nhö
min(), max(), baïn seõ tìm hieåu ôû Chöông 3.
Vôùi caùc tính naêng vöôït troäi naøy, taïi sao ngöôøi ta laïi khoâng taïo index trong taát caû caùc field cuûa
moät table? Coù moät soá ñieàu trôû ngaïi nhö sau: Thöù nhaát, index coù seõ laøm chaäm moät soá tieán
trình trong CSDL. Moãi laàn baûo trì caùc index Database Server phaûi maát khaù nhieàu thôøi gian.
Coù moät vaøi tröôøng hôïp chính caùc index laøm cho chuùng chaäm haún. Neáu nhö treân table cuûa baïn
taát caû caùc record ñeàu gioáng y nhö nhau thì khoâng coù lyù do gì ñeå baïn taïo index. Caùc index dö
thöøa chæ laøm cho toán theâm khoâng gian ñóa cuûa baïn maø thoâi.
49. Ñoái vôùi moät table coù gaén khoaù chính (primary key) thì thoâng thöôøng field coù khoaù naøy ñöôïc
duøng vaøo vieäc tìm kieám cho neân index seõ ñöôïc gaùn töï ñoäng treân field naøy.
Baïn seõ gaëp laïi raát nhieàu coâng vieäc taïo index ôû caùc phaàn tieáp theo sau.
Leänh CREATE Database
Tröôùc khi taïo ñöôïc moät Table thì ñieàu taát yeáu laø baïn phaûi taïo ñöôïc moät Database caùi ñaõ.
Vieäc naøy deã daøng vaø nhanh choùng thoâi. Leänh CREATE ñöôïc söû duïng nhö sau:
mysql> create database database_name;
Neáu nhö baïn thaéc maéc raèng sau khi taïo database noù seõ naèm ôû trong thö muïc naøo treân oå ñóa cuûa baïn thì baïn haõy
tìm trong ..mysqldata xem coù khoâng.
Khi ñaët teân cho database, hay ñaët teân cho field vaø index gì ñaáy traùnh tröôøng traùnh tröôøng hôïp
ñaët nhöõng caùi teân khoù nhôù hoaëc deã bò laãn loän. Ñoái vôùi moät soá heä thoáng Unix chaúng haïn coù söï
phaân bieät chöõ HOA/thöôøng thì CSDL chaïy treân noù cuõng aûnh höôûng theo.
Baïn haõy choïn moät quy öôùc cho rieâng mình trong vieäc ñaët teân ñeå khoûi nhaàm laãn veà sau.
Chaúng haïn teân cuûa table vaø field ñeàu ñaët chöõ thöôøng chaúng haïn. Neân nhôù laø khoâng ñöôïc söû
duïng khoaûng traéng.
50. Baây giôø baïn tìm hieåu caû hai caùch taïo database: Caùch thöù nhaát taïo thuû coâng töø daáu nhaéc doøng
leänh DOS, caùch thöù hai söû duïng caùc leänh trong PHP.
Caùch thöù nhaát toâi ñaõ coù trình baøy ôû chöông giôùi thieäu vaø baïn ñaõ taïo moät database teân laø
guestbook. Cuù phaùp taïo nhö sau:
mysql> create database guestbook;
Caùch thöù hai laø söû duïng leänh trong PHP, baïn coù theå duøng haøm mysql_create_db() hoaëc
mysql_query(). Nhöng neân nhôù tröôùc khi taïo baïn phaûi thöïc hieän ñöôïc keát noái vôùi database
server.
$conn = mysql_connect(“localhost”,”username”, “password”)
or die (“Could not connect to localhost”);
mysql_create_db(“my_database”) or
die (“Could not create database”);
$string = “create database my_other_db”;
mysql_query($string) or
die(mysql_error());
51. Leänh USE Database
Sau khi ñaõ taïo ñöôïc moät database môùi trong database server baïn seõ baét ñaàu choïn noù ñeå söû
duïng cho coâng vieäc cuûa mình. Caùch thöïc hieän nhö sau:
1. Command Prompt:
mysql> use database_name;
2. Trong PHP:
$conn = mysql_connect(“localhost”,”username”, “password”)
or die (“Could not connect to localhost”);
mysql_select_db(“test”, $conn) or
die (“Could not select database”);
52. Leänh CREATE Table
Löu yù: Leänh naøy thöïc hieän sau khi ñaõ coù leänh CREATE Database.
Moät khi baïn ñaõ taïo vaø choïn database, vieäc tieáp theo laø taïo moät table. Baïn seõ söû duïng leänh
Create Table nhö sau:
create table table_name
(
column_1 column_type column_attributes,
column_2 column_type column_attributes,
primary key (column_name),
index index_name(column_name)
)
Ñoái vôùi thuoäc tính caùc field (coät) chuùng ta caàn baøn veà:
- null hoaëc not null
- default
53. Neáu baïn khoâng ñònh nghóa NULL hay NOT NULL thì NULL seõ ñöôïc choïn laøm giaù trò maëc
ñònh. Haõy xeùt ví duï sau:
create table topics2 (
topic_id integer not null auto_increment,
parent_id integer default 0 not null,
root_id integer default 0,
name varchar(255),
description text null,
create_dt timestamp,
modify_dt timestamp,
author varchar(255) null,
author_host varchar(255) null,
primary key(topic_id),
index my_index(parent_id))
Trong ví duï treân baïn taïo ra moät table coù teân topics2, coù taát caû 8 field vaø coù 2 index, moät
index cho khoaù chính vaø moät cho parent_id. Type cuûa caùc field treân laàn löôït laø integer,
varchar, text, timestamp. Giaù trò ñöùng sau defaul laø giaù trò maëc ñònh baïn gaùn cho moät oâ trong
record khi khoâng nhaäp lieäu vaøo.
54. Baây giôø chuùng ta aùp duïng caùc leänh naøy vaøo moät chöông trình PHP ñeå taïo table, haøm
mysql_query () ñöôïc söû duïng:
$conn = mysql_connect(“localhost”,”username”, “password”) or
die (“Could not connect to localhost”);
mysql_select_db(“test”, $conn) or
die(“could not select database”);
$query = “create table my_table (col_1 int not null primary key,
col_2 text)”;
mysql_query($query) or
die(mysql_error());
* Löu yù: username vaø password tuyø thuoäc vaøo MySQL cuûa baïn.Ví duï:
$conn = mysql_connect(“localhost”,”minhtrung”, “zadfdfaked”) or
Thoâng thöôøng caùc nhaø cung caáp host PHP söû duïng localhost, tuy nhieân moät soá hosting khoâng söû duïng localhost
nhö Yahoo chaúng haïn. Do ñoù baïn caàn xem höôùng daãn cuûa nhaø cung caáp host.
55. Kieåu döõ lieäu
Baây giôø chuùng ta haõy baøn veà caùc kieåu döõ lieäu (type) gaùn cho field trong table. Coù raát nhieàu
kieåu khaùc nhau chuùng ta seõ laàn löôït khaûo saùt töøng kieåu moät.
Kieåu chuoãi vaên baûn
MySQL coù 7 kieåu daønh cho döõ lieäu kieåu chuoãi vaên baûn:
char
varchar
tinytext
text
mediumtext
longtext
enum
71. Leänh Alter table
Neáu nhö baïn muoán thay ñoåi caùc thaønh phaàn cuûa table baïn seõ söû duïng leänh alter table. Baïn coù
theå thöïc hieän caùc thay ñoåi nhö: ñoåi teân table, field, index; theâm hoaëc xoaù field vaø index; ñònh
nghóa laïi caùc field vaø index. Cuù phaùp cô baûn cuûa leänh naøy laø:
alter table table_name
Caùc leänh coøn laïi tuyø thuoäc vaøo thao taùc maø chuùng ta seõ baøn tieáp theo ñaây:
Ñoåi teân Table
Cuù phaùp nhö sau:
alter table table_name rename new_table_name
If you have MySQL version 3.23.27 or higher you can make use of the
rename statement.The basic syntax is
rename table_name to new_table_name
72. Theâm vaø xoaù coät trong Table
Khi theâm field vaøo trong table, baïn seõ caàn phaûi coù nhöõng ñònh nghóa caàn thieát cho field ñoù.
Töø phieân baûn 3.22 cuûa MySQL cho pheùp baïn choïn vò trí ñeå ñaët field môùi vaøo trong table.
Chöùc naêng naøy khoâng baét buoäc.
alter table table_name add column column_name column attributes
Ví duï:
alter table my_table add column my_column text not null
Caùch söû duïng ñònh vò moät field trong table: Söû duïng leänh first ñeå cheøn field môùi vaøo vò trí ñaàu
cuûa table. After ñeå cheøn vaøo vò trí sau cuøng treân table:
alter table my_table add column my_next_col text not null first
alter table my_table add column my_next_col text not null after
my_other_column
Ñeå xoaù moät field, baïn thöïc hieän leänh sau:
73. alter table table_name drop column column name
Khi thöïc hieän leänh alter ñoái vôùi moät table, baïn chæ neân thöïc hieän moät thao taùc ñoái vôùi table maø thoâi. Ví duï: Baïn
thöïc hieän vieäc xoaù moät index, sau ñoù taïo moät index môùi, thì khoâng neân goäp chung vaøo moät leänh alter maø neân
thöïc hieän 2 laàn.
Theâm vaø xoaù Index
Baïn coù theå theâm index baèng caùch söû duïng leänh index, unique vaø primary key, töông töï nhö
vieäc söû duïng leänh create vaäy.
alter table my_table add index index_name (column_name1,
column_name2, ...)
alter table my_table add unique index_name(column_name)
alter table my_table add primary key(my_column)
Baïn cuõng coù theå boû index baèng caùch söû duïng leänh drop:
alter table table_name drop index index_name
alter table_name test10 drop primary key
74. Ñoåi thuoäc tính cuûa coät (field)
Thay ñoåi caùch thaønh toá cuûa field baèng leänh change hoaëc modify:
alter table table_name change original_column_name new_column_name
int not null
Leänh sau laø sai:
alter table table_name change my_col2 my_col3;
Neáu baïn muoán chæ ñoåi thuoäc tính cuûa field thì duøng leänh change vaø taïo field môùi cuøng teân
nhöng thay ñoåi thuoäc tính. Giaû duï baïn ñoåi field col_1 töø kieåu char(200) sang varchar(200):
alter table table_name change col_1 col_1 varchar(200)
Vôùi MySQL phieân baûn 2.22.16 trôû ñi baïn coù theå duøng leänh modify:
alter table table_name modify 1 col_1 varchar(200)
