Query languages commonly used in ThinkPHP
This article mainly introduces a summary of common query languages in ThinkPHP. It is a commonly used technique in ThinkPHP. It is very practical in project development. Friends in need can refer to it.
This article summarizes the examples of ThinkPHP Commonly used query languages in are provided for your reference. I believe it can bring some help to everyone's ThinkPHP development. The details are as follows:
1. Ordinary query:
When the query brings in where conditions, etc., there are at least three forms
1. Characters String form:
'id>5 and id<9'
2. Array form:
The sample code is as follows:
$user=M('user'); $data['username']='liwenkai'; $list=$user->where(array('username'=>'liwenkai'))->select(); $list=$user->where($data)->select();
3. Object form:
The sample code is as follows:
$user=M('user'); $a=new stdClass(); $a->username='liwenkai'; $list=$user->where($a)->select();
4. Query expression:
EQ can be equal to
NEQ can not be equal to
GT can be greater than
EG can can be greater than or equal to
LT can ELT Less than or equal to
LIKE Equivalent to like
[NOT] BETWEEN in SQL
Commonly used forms:
$data['字段名']=array('是表达式','查询条件');
In addition
$data['liwenkai']='liwenkai';
is actually equivalent to
$data['liwenkai']=array('eq','liwenkai');
The example is as follows:
$data['username']=array('like','peng%'); $list=$user->where($data)->select();2. Interval query:
Examples are as follows:
$user=M('user'); $data['id']=array(array('gt',20),array('lt',23),'and'); $list=$user->where($data)->select(); dump($list);
$data['username']=array(array('like','p%'),array('like','h%'),'or');3. Combined query :
The example is as follows:
$user=M('user'); $data['username']='pengyanjie'; $data['password']=array('eq','pengyanjie'); $data['id']=array('lt',30); $data['_logic']='or'; $list=$user->where($data)->select(); dump($list);
##4. Compound query:
Example As follows:$user=M('user'); $data['username']=array('eq','pengyanjie'); $data['password']=array('like','p%'); $data['_logic']='or'; $where['_complex']=$where; $where['id']=array('lt',30); $list=$user->where($data)->select(); dump($list);is equivalent to
(id<30)and ( (username=pengyanjie) or (password like p%) )
5. Statistical query:
Examples are as follows:echo $user->count(); echo '<br>'; echo $user->max('id'); echo '<br>'; echo $user->where('id<30')->min('id'); echo '<br>'; echo $user->avg('id'); echo '<br>'; echo $user->sum('id');
6. Positioning query:
Examples are as follows :$user=new AdvModel('user');//实例化高级模型AdvModel //$user=M('user','CommonModel');//或者将AdvModel用CommonModel来继承 $list=$user->order('id desc')->getN(2);//返回结果中的第三条 dump($list); $list=$user->order('id desc')->last();//返回最后一条 $list=$user->order('id desc')->first();//返回第一条
7. SQL query:
1.excute() is mainly used for updating and Write:
$Model = new Model() // 实例化一个 model 对象 没有对应任何数据表 $Model->execute( "update think_user set name='thinkPHP' where status=1" );
2.query() is mainly used to query:
$user=M(); $list=$user->query('select * from aoli_user order by id desc'); dump($list);##8. Dynamic query
The example is as follows:
$user=M('user');
$list=$user->getByusername('pengyanjie');
$list=$user->getByusername('pengyanjie');
dump($list);
$user=new AdvModel('user'); $list=$user->top5();//前5条 dump($list);
The above is the entire content of this article. I hope it will be helpful to everyone’s study. For more related content, please pay attention to the PHP Chinese website!
Related recommendations:
How to execute native SQL statements in thinkPHP frameworkThinkPHP implements conversion of database query result data to corresponding type
The above is the detailed content of Query languages commonly used in ThinkPHP. For more information, please follow other related articles on the PHP Chinese website!

Reasons for PHPSession failure include configuration errors, cookie issues, and session expiration. 1. Configuration error: Check and set the correct session.save_path. 2.Cookie problem: Make sure the cookie is set correctly. 3.Session expires: Adjust session.gc_maxlifetime value to extend session time.

Methods to debug session problems in PHP include: 1. Check whether the session is started correctly; 2. Verify the delivery of the session ID; 3. Check the storage and reading of session data; 4. Check the server configuration. By outputting session ID and data, viewing session file content, etc., you can effectively diagnose and solve session-related problems.

Multiple calls to session_start() will result in warning messages and possible data overwrites. 1) PHP will issue a warning, prompting that the session has been started. 2) It may cause unexpected overwriting of session data. 3) Use session_status() to check the session status to avoid repeated calls.

Configuring the session lifecycle in PHP can be achieved by setting session.gc_maxlifetime and session.cookie_lifetime. 1) session.gc_maxlifetime controls the survival time of server-side session data, 2) session.cookie_lifetime controls the life cycle of client cookies. When set to 0, the cookie expires when the browser is closed.

The main advantages of using database storage sessions include persistence, scalability, and security. 1. Persistence: Even if the server restarts, the session data can remain unchanged. 2. Scalability: Applicable to distributed systems, ensuring that session data is synchronized between multiple servers. 3. Security: The database provides encrypted storage to protect sensitive information.

Implementing custom session processing in PHP can be done by implementing the SessionHandlerInterface interface. The specific steps include: 1) Creating a class that implements SessionHandlerInterface, such as CustomSessionHandler; 2) Rewriting methods in the interface (such as open, close, read, write, destroy, gc) to define the life cycle and storage method of session data; 3) Register a custom session processor in a PHP script and start the session. This allows data to be stored in media such as MySQL and Redis to improve performance, security and scalability.

SessionID is a mechanism used in web applications to track user session status. 1. It is a randomly generated string used to maintain user's identity information during multiple interactions between the user and the server. 2. The server generates and sends it to the client through cookies or URL parameters to help identify and associate these requests in multiple requests of the user. 3. Generation usually uses random algorithms to ensure uniqueness and unpredictability. 4. In actual development, in-memory databases such as Redis can be used to store session data to improve performance and security.

Managing sessions in stateless environments such as APIs can be achieved by using JWT or cookies. 1. JWT is suitable for statelessness and scalability, but it is large in size when it comes to big data. 2.Cookies are more traditional and easy to implement, but they need to be configured with caution to ensure security.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

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

Hot Article

Hot Tools

SecLists
SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.

PhpStorm Mac version
The latest (2018.2.1) professional PHP integrated development tool

SublimeText3 Chinese version
Chinese version, very easy to use

MantisBT
Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

Atom editor mac version download
The most popular open source editor
