国产av日韩一区二区三区精品,成人性爱视频在线观看,国产,欧美,日韩,一区,www.成色av久久成人,2222eeee成人天堂

current location：Home > Technical Articles > Daily Programming

  • mysql delete from table where
    mysql delete from table where
    When deleting data using the DELETEFROMtableWHERE statement in MySQL, you must pay attention to accuracy and security. 1. This statement is used to delete records according to the specified conditions. If the WHERE condition is omitted, the entire table will be cleared; 2. Common problems include field name errors, string not quoted, improper LIKE match, etc. It is recommended to use SELECT to confirm the target data before deletion; 3. In actual operations, the principles of checking first and then deleting, adding LIMIT tests, using transaction processing, and early backup should be followed; 4. When deleting a large amount of data, it is necessary to execute it in batches to avoid table locking and performance problems. If necessary, TRUNCATE or DROP tables should be considered.
    Mysql Tutorial . Database 739 2025-07-12 01:24:51
  • What is Atomic CSS (or Functional CSS)?
    What is Atomic CSS (or Functional CSS)?
    AtomicCSS is a CSS writing method that only does one thing per class, improving efficiency and collaboration by combining a class with a single function. It solves the problems of style duplication and naming problems, and is suitable for rapid development and team collaboration. Common tools include TailwindCSS, WindiCSS and UnoCSS, which are used in conjunction with the construction tools. Applicable scenarios include prototype construction, design system and style unified project. Notes include learning costs, increased HTML complexity and lengthy class names. It is recommended to encapsulate high-frequency components, simplify combinations using @apply, and maintain consistency in code formatting.
    CSS Tutorial . Web Front-end 287 2025-07-12 01:24:10
  • Using CSS Background-size: cover and contain effectively
    Using CSS Background-size: cover and contain effectively
    The choice of background-size:cover and contain depends on content priority. 1. Cover zoom images ensure that the entire container is covered, and some content may be cropped, which is suitable for scenes where the background is only decorative and the area needs to be filled; 2. Contain zoom images ensure that the complete display is displayed, and may leave blank space, which is suitable for scenes where the content of the picture is important and cannot be cropped; 3. When using it, you should judge based on specific needs, and if necessary, a background-position should be used to control the crop position to ensure a reasonable visual center of gravity.
    CSS Tutorial . Web Front-end 400 2025-07-12 01:22:40
  • What are Twitter Card meta tags?
    What are Twitter Card meta tags?
    TwitterCardmetatagsareHTMLcodesnippetsthatcontrolhowlinksappearwhensharedonTwitter.1.Theyenablerichcontentpreviewswithtitles,descriptions,andimages.2.CommontypesincludeSummaryCard,SummaryCardwithLargeImage,AppCard,andPlayerCard.3.Essentialtagsaretwit
    HTML Tutorial . Web Front-end 513 2025-07-12 01:18:11
  • mysql ifnull function
    mysql ifnull function
    IFNULL is a function in MySQL used to process NULL values. Its function is to return the first parameter when it is not NULL, otherwise it returns the second parameter. 1. Common usages include replacing the NULL value in the query results, such as "not filled in" when the phone is empty; 2. Prevent NULL from causing the entire result to be NULL in the operation, such as replacing the price of NULL with 0 and participating in multiplication calculation; 3. Use it in combination with the aggregate function to ensure that the results such as SUM are not NULL; 4. Notes include trying to keep the parameter types consistent, not be able to judge multiple NULLs, and avoiding covering up the business logic meaning; 5. It is very practical when using practical applications such as displaying user addresses or calculating employee income. Overall, IFNULL is a simple and effective
    Mysql Tutorial . Database 672 2025-07-12 01:15:31
  • What is the HTML inert attribute?
    What is the HTML inert attribute?
    TheinertattributeinHTMLmakeselementsnon-interactiveandinaccessibletousers.1.Itpreventsfocus,clicks,textselection,andscreenreaderaccess.2.Itisusefulformodals,tabbedinterfaces,loadingstates,andconditionalUIs.3.Browsersupportislimited,especiallyinSafari
    HTML Tutorial . Web Front-end 283 2025-07-12 01:11:12
  • What are PHP Magic Methods and how are they invoked?
    What are PHP Magic Methods and how are they invoked?
    The PHP magic method is an automatically triggered built-in function that responds to specific behaviors in object interactions. They start with double underscores and are automatically executed in specific scenarios; __construct() is called when the object is created and is used to initialize operations; __destruct() is called before the object is destroyed, suitable for cleaning resources; __get() and __set() handle dynamic access to inaccessible properties; __call() and __callStatic() are used to handle undefined instance methods and static method calls; other examples such as __sleep(), __wakeup(), __toString(), and __invoke() are serialized, deserialized, and object conversion respectively.
    PHP Tutorial . Backend Development 879 2025-07-12 01:09:10
  • PHP undefined index $_POST
    PHP undefined index $_POST
    When encountering a PHPundefinedindex$_POST error, you need to clarify the answer first: this is caused by accessing the key value that does not exist in the $_POST array. Common reasons and solutions include: 1. Check whether the form field names are consistent, and ensure that the key names in the PHP code are exactly the same as the HTML form name attribute; 2. Confirm that the form is submitted correctly and the method type is post, check whether there is JS blocking submission and use the developer tools to confirm that the POST request is issued; 3. Use isset or !empty to judge the $_POST field to avoid directly accessing non-existent indexes; 4. For fields that may not be selected such as check boxes, pre-assign default values ??to prevent undefined errors. Pass
    PHP Tutorial . Backend Development 764 2025-07-12 01:08:11
  • PHP header location needs exit
    PHP header location needs exit
    The answer is: It is recommended to add exit, but not mandatory. After using header('Location:...') in PHP, the script will continue to execute subsequent code, which may lead to unnecessary output, security risks or logical errors; therefore, it is recommended to add exit or die to terminate the script; if there is no other logic after the jump and the script ends naturally, exit can be omitted; to ensure security and clear code, it is recommended to use header exit combination or encapsulate jump functions in a unified manner.
    PHP Tutorial . Backend Development 511 2025-07-12 01:03:21
  • How to create a sticky header or footer in HTML?
    How to create a sticky header or footer in HTML?
    To enable the navigation bar or bottom information in a web page to always display on the screen, use CSS' position:sticky. 1. You need to set position:sticky and top:0 to create StickyHeader, and make sure that the parent element has no overflow:hidden restrictions. It is also recommended to set background color and z-index to avoid content being exposed and overwritten; 2. Use position:sticky and bottom:0 to create StickyFooter, but if you want the footer to be fixed at the bottom of the screen regardless of the length of the content, you should use position:fixed; 3. If sticky is invalid, common reasons include not setting
    HTML Tutorial . Web Front-end 888 2025-07-12 00:56:32
  • how to get table size in mysql
    how to get table size in mysql
    To see how much space a table occupies in MySQL, you can achieve it in the following ways: 1. Query the size of a single table, use SQL statements to obtain the data and index size from information_schema.tables; 2. Check the size of all tables in the entire database, and list all tables through information_schema.tables and sort them by total size; 3. Use the SHOWTABLESTATUS command to quickly view the size information of the table, and pay attention to unit conversion. In addition, you should ensure access when performing these operations, and consider storage engine differences and statistical accuracy issues.
    Mysql Tutorial . Database 145 2025-07-12 00:55:10
  • Implementing Native Lazy Loading for Images in HTML
    Implementing Native Lazy Loading for Images in HTML
    Native lazy loading is a built-in browser function that enables lazy loading of pictures by adding loading="lazy" attribute to the tag. 1. It does not require JavaScript or third-party libraries, and is used directly in HTML; 2. It is suitable for pictures that are not displayed on the first screen below the page, picture gallery scrolling add-ons and large picture resources; 3. It is not suitable for pictures with first screen or display:none; 4. When using it, a suitable placeholder should be set to avoid layout jitter; 5. It should optimize responsive image loading in combination with srcset and sizes attributes; 6. Compatibility issues need to be considered. Some old browsers do not support it. They can be used through feature detection and combined with JavaScript solutions.
    HTML Tutorial . Web Front-end 800 2025-07-12 00:48:31
  • How to add an image in HTML
    How to add an image in HTML
    To display images on web pages, use the HTML img tag, the syntax is: imgsrc="image path" alt="alternative text". 1. The src attribute specifies the image path, supports relative paths or absolute URLs; 2. The alt attribute is used for alternative text when the image cannot be loaded and improves barrier-free access; 3. You can set the size through width and height, or use CSS to control the style more flexibly; 4. Other common attributes include title (prompt text), loading="lazy" (lazy loading), class or id (with CSS); 5. It is recommended to use .jpg and .png
    HTML Tutorial . Web Front-end 413 2025-07-12 00:28:22
  • PHP string to uppercase
    PHP string to uppercase
    There are four main ways to convert strings to uppercase in PHP, and the specific choice depends on the usage scenario. 1. Use strtoupper() to convert lowercase letters of the entire string to uppercase, which are suitable for English content, but do not support non-English characters with accents; 2. When dealing with multilinguals, mb_strtoupper() is recommended. It belongs to the mbstring extension and can correctly convert special characters such as French and German. It is recommended to specify the character set to UTF-8 when using it; 3. If you only need to convert the first letter, you can use ucfirst() to convert the first character of the string to uppercase; 4. If you want the first letter of each word to uppercase, you can use ucwords() to be used, which is suitable for formatting titles or usernames to display, but it does not recognize underscores by default.
    PHP Tutorial . Backend Development 934 2025-07-12 00:27:20

Tool Recommendations

jQuery enterprise message form contact code

jQuery enterprise message form contact code is a simple and practical enterprise message form and contact us introduction page code.
form button
2024-02-29

HTML5 MP3 music box playback effects

HTML5 MP3 music box playback special effect is an mp3 music player based on HTML5 css3 to create cute music box emoticons and click the switch button.

HTML5 cool particle animation navigation menu special effects

HTML5 cool particle animation navigation menu special effect is a special effect that changes color when the navigation menu is hovered by the mouse.
Menu navigation
2024-02-29

jQuery visual form drag and drop editing code

jQuery visual form drag and drop editing code is a visual form based on jQuery and bootstrap framework.
form button
2024-02-29

Organic fruit and vegetable supplier web template Bootstrap5

An organic fruit and vegetable supplier web template-Bootstrap5
Bootstrap template
2023-02-03

Bootstrap3 multifunctional data information background management responsive web page template-Novus

Bootstrap3 multifunctional data information background management responsive web page template-Novus
backend template
2023-02-02

Real estate resource service platform web page template Bootstrap5

Real estate resource service platform web page template Bootstrap5
Bootstrap template
2023-02-02

Simple resume information web template Bootstrap4

Simple resume information web template Bootstrap4
Bootstrap template
2023-02-02

Cute summer elements vector material (EPS PNG)

This is a cute summer element vector material, including the sun, sun hat, coconut tree, bikini, airplane, watermelon, ice cream, ice cream, cold drink, swimming ring, flip-flops, pineapple, conch, shell, starfish, crab, Lemons, sunscreen, sunglasses, etc., the materials are provided in EPS and PNG formats, including JPG previews.
PNG material
2024-05-09

Four red 2023 graduation badges vector material (AI EPS PNG)

This is a red 2023 graduation badge vector material, four in total, available in AI, EPS and PNG formats, including JPG preview.
PNG material
2024-02-29

Singing bird and cart filled with flowers design spring banner vector material (AI EPS)

This is a spring banner vector material designed with singing birds and a cart full of flowers. It is available in AI and EPS formats, including JPG preview.
banner picture
2024-02-29

Golden graduation cap vector material (EPS PNG)

This is a golden graduation cap vector material, available in EPS and PNG formats, including JPG preview.
PNG material
2024-02-27

Home Decor Cleaning and Repair Service Company Website Template

Home Decoration Cleaning and Maintenance Service Company Website Template is a website template download suitable for promotional websites that provide home decoration, cleaning, maintenance and other service organizations. Tip: This template calls the Google font library, and the page may open slowly.
Front-end template
2024-05-09

Fresh color personal resume guide page template

Fresh color matching personal job application resume guide page template is a personal job search resume work display guide page web template download suitable for fresh color matching style. Tip: This template calls the Google font library, and the page may open slowly.
Front-end template
2024-02-29

Designer Creative Job Resume Web Template

Designer Creative Job Resume Web Template is a downloadable web template for personal job resume display suitable for various designer positions. Tip: This template calls the Google font library, and the page may open slowly.
Front-end template
2024-02-28

Modern engineering construction company website template

The modern engineering and construction company website template is a downloadable website template suitable for promotion of the engineering and construction service industry. Tip: This template calls the Google font library, and the page may open slowly.
Front-end template
2024-02-28