search
HomeBackend DevelopmentPHP TutorialSome issues that need to be paid attention to when operating MySQL database in PHP (translated) Some issues are very well said. . Quite novel. . -Database related_PHP tutorial

Some issues to pay attention to when operating MySQL database in PHP
1. Semicolon exceptions
For MySQL, the first thing you must remember is that each line of commands ends with a semicolon (;) , but... there is no absolute thing, and it is the same here. When a line of MySQL is inserted into the PHP code, it is best to omit the following semicolon, for example:
mysql_query ("INSERT INTO tablename (first_name, last_name)
VALUES ('$first_name', '$last_name')
");
This is because PHP also ends a line with a semicolon, and extra semicolons sometimes make PHP's syntax The parser doesn't understand it, so it's better to omit it. In this case, although the semicolon is omitted, PHP will automatically add it for you when executing the MySQL command.

There is another situation where you don’t need to add a semicolon. When you want to display the vertical arrangement of the fields you want instead of the usual horizontal arrangement, you can use G to end a line of SQL statements. In this case, there is no need for a semicolon, for example:
SELECT * FROM PENPALS WHERE USER_ID = 1G  
2. TEXT, DATE, and SET data types  
The fields of the MySQL data table must have a data type defined. There are about 25 options, most of which are straightforward and require no further explanation. But there are a few that need to be mentioned.

TEXT is not a data type, although some books may say so. It should actually be "LONG VARCHAR" or "MEDIUMTEXT".

The format of DATE data type is YYYY-MM-DD, for example: 1999-12-08. You can easily use the date function to get the current system time in this format:
date("Y-m-d")
Moreover, you can subtract between DATA data types to get the difference in days:
$age = ($current_date - $birthdate);
Set SET is a useful data type. It is somewhat similar to enumeration ENUM, except that SET can save multiple values ​​and ENUM can only save one value. Moreover, the SET type can only have a maximum of 64 predefined values, while the ENUM type can handle a maximum of 65,535 predefined values. And what if we need a collection with more than 64 values? At this time, you need to define multiple collections to solve this problem together.

3. Wildcard

www.bkjia.comtruehttp: //www.bkjia.com/PHPjc/631431.htmlTechArticleSome issues to pay attention to when operating MySQL database in PHP 1. Semicolon exception For MySQL, the first thing you should do It must be remembered that each line of commands ends with a semicolon (;), but...
Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
The Continued Use of PHP: Reasons for Its EnduranceThe Continued Use of PHP: Reasons for Its EnduranceApr 19, 2025 am 12:23 AM

What’s still popular is the ease of use, flexibility and a strong ecosystem. 1) Ease of use and simple syntax make it the first choice for beginners. 2) Closely integrated with web development, excellent interaction with HTTP requests and database. 3) The huge ecosystem provides a wealth of tools and libraries. 4) Active community and open source nature adapts them to new needs and technology trends.

PHP and Python: Exploring Their Similarities and DifferencesPHP and Python: Exploring Their Similarities and DifferencesApr 19, 2025 am 12:21 AM

PHP and Python are both high-level programming languages ​​that are widely used in web development, data processing and automation tasks. 1.PHP is often used to build dynamic websites and content management systems, while Python is often used to build web frameworks and data science. 2.PHP uses echo to output content, Python uses print. 3. Both support object-oriented programming, but the syntax and keywords are different. 4. PHP supports weak type conversion, while Python is more stringent. 5. PHP performance optimization includes using OPcache and asynchronous programming, while Python uses cProfile and asynchronous programming.

PHP and Python: Different Paradigms ExplainedPHP and Python: Different Paradigms ExplainedApr 18, 2025 am 12:26 AM

PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.

PHP and Python: A Deep Dive into Their HistoryPHP and Python: A Deep Dive into Their HistoryApr 18, 2025 am 12:25 AM

PHP originated in 1994 and was developed by RasmusLerdorf. It was originally used to track website visitors and gradually evolved into a server-side scripting language and was widely used in web development. Python was developed by Guidovan Rossum in the late 1980s and was first released in 1991. It emphasizes code readability and simplicity, and is suitable for scientific computing, data analysis and other fields.

Choosing Between PHP and Python: A GuideChoosing Between PHP and Python: A GuideApr 18, 2025 am 12:24 AM

PHP is suitable for web development and rapid prototyping, and Python is suitable for data science and machine learning. 1.PHP is used for dynamic web development, with simple syntax and suitable for rapid development. 2. Python has concise syntax, is suitable for multiple fields, and has a strong library ecosystem.

PHP and Frameworks: Modernizing the LanguagePHP and Frameworks: Modernizing the LanguageApr 18, 2025 am 12:14 AM

PHP remains important in the modernization process because it supports a large number of websites and applications and adapts to development needs through frameworks. 1.PHP7 improves performance and introduces new features. 2. Modern frameworks such as Laravel, Symfony and CodeIgniter simplify development and improve code quality. 3. Performance optimization and best practices further improve application efficiency.

PHP's Impact: Web Development and BeyondPHP's Impact: Web Development and BeyondApr 18, 2025 am 12:10 AM

PHPhassignificantlyimpactedwebdevelopmentandextendsbeyondit.1)ItpowersmajorplatformslikeWordPressandexcelsindatabaseinteractions.2)PHP'sadaptabilityallowsittoscaleforlargeapplicationsusingframeworkslikeLaravel.3)Beyondweb,PHPisusedincommand-linescrip

How does PHP type hinting work, including scalar types, return types, union types, and nullable types?How does PHP type hinting work, including scalar types, return types, union types, and nullable types?Apr 17, 2025 am 12:25 AM

PHP type prompts to improve code quality and readability. 1) Scalar type tips: Since PHP7.0, basic data types are allowed to be specified in function parameters, such as int, float, etc. 2) Return type prompt: Ensure the consistency of the function return value type. 3) Union type prompt: Since PHP8.0, multiple types are allowed to be specified in function parameters or return values. 4) Nullable type prompt: Allows to include null values ​​and handle functions that may return null values.

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Atom editor mac version download

Atom editor mac version download

The most popular open source editor

SublimeText3 Linux new version

SublimeText3 Linux new version

SublimeText3 Linux latest version

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

SublimeText3 English version

SublimeText3 English version

Recommended: Win version, supports code prompts!

SAP NetWeaver Server Adapter for Eclipse

SAP NetWeaver Server Adapter for Eclipse

Integrate Eclipse with SAP NetWeaver application server.