How to encapsulate PHP database operation function library

With the rapid development of the Internet, databases have become an important part of many websites and applications. Database operations are also one of the basic operations of websites and applications. With the development of PHP language, PHP has become the development language for most websites and applications. The MySQL extension library and its encapsulation functions provided by PHP enable PHP to easily interact with the MySQL database and realize the addition, deletion, modification and query operations of the database.

In actual development, function libraries that encapsulate database operations can greatly improve development efficiency and code readability. In this article, we will introduce how to encapsulate the PHP database operation function library and demonstrate how to perform add, delete, modify and query operations.

1. Environment preparation

Before introducing the encapsulated PHP database operation function library, we need to prepare the corresponding development environment, including PHP, MySQL and the required extension libraries.

In PHP, the mysql extension is a commonly used MySQL operation extension, and the mysqli extension is a MySQL operation extension recommended for PHP5 and above. In this article, we will use the mysqli extension as an example to explain.

2. Database connection

Before performing database operations, we need to establish a connection with the database first. The code to establish a database connection is as follows:

$link = mysqli_connect('localhost','username','password','database') or die ('连接数据库失败！');

Among them, 'localhost' represents the host address where the database is located, 'username' and 'password' represent the username and password of the database respectively, and 'database' represents the name of the database to be connected. . If the connection fails, the program will return an error message and exit.

3. Database operation

1. Database query

The code for database query is as follows:

function db_query($sql) {
    $link = mysqli_connect('localhost','username','password','database') or die ('连接数据库失败！');
    $result = mysqli_query($link, $sql);
    mysqli_close($link);
    return $result;
}

This code converts the SQL statement Passed into the function as a parameter, first connect to the MySQL database through the mysqli_connect function, then execute the SQL statement through the mysqli_query function, and store the query results in the $result variable. Finally, the database connection is closed through the mysqli_close function and the query results are returned.

2. Database insertion

The code for database insertion is as follows:

function db_insert($table, $data) {
    $link = mysqli_connect('localhost','username','password','database') or die ('连接数据库失败！');
    $fields = array();
    $values = array();
    foreach ($data as $key => $value) {
        $fields[] = "`".$key."`";
        $values[] = "'".$value."'";
    }
    $fields = implode(",", $fields);
    $values = implode(",", $values);
    $sql = "INSERT INTO `".$table."` (".$fields.") VALUES (".$values.")";
    $result = mysqli_query($link, $sql);
    mysqli_close($link);
    return $result;
}

This code passes the data to be inserted into the function as a parameter and traverses the data Array, extract the fields and values ​​of the data, and then splice them into the field and value parts in the SQL statement through the implode function. Finally, the SQL statement is executed through the mysqli_query function, the data is inserted into the specified table, the database connection is closed through the mysqli_close function, and the insertion result is returned.

3. Database update

The code for database update is as follows:

function db_update($table, $data, $where) {
    $link = mysqli_connect('localhost','username','password','database') or die ('连接数据库失败！');
    $fields = array();
    foreach ($data as $key => $value) {
        $fields[] = "`".$key."`='".$value."'";
    }
    $fields = implode(",", $fields);
    $where = " WHERE ".$where;
    $sql = "UPDATE `".$table."` SET ".$fields.$where;
    $result = mysqli_query($link, $sql);
    mysqli_close($link);
    return $result;
}

This code takes the data to be updated, update conditions and update table name as parameters Pass in the function, traverse the data array, extract the fields and values ​​of the data, and then use the implode function to splice them into the field and value parts of the SQL statement. Then splice the update conditions into a WHERE clause, execute the SQL statement through the mysqli_query function, update the data to the specified table, close the database connection through the mysqli_close function, and return the update result.

4. Database deletion

The code for database deletion is as follows:

function db_delete($table, $where) {
    $link = mysqli_connect('localhost','username','password','database') or die ('连接数据库失败！');
    $where = " WHERE ".$where;
    $sql = "DELETE FROM `".$table."`".$where;
    $result = mysqli_query($link, $sql);
    mysqli_close($link);
    return $result;
}

This code passes the data to be deleted and the deletion conditions as parameters into the function. , splice the conditions into a WHERE clause, execute the SQL statement through the mysqli_query function, delete the specified data from the table, close the database connection through the mysqli_close function, and return the deletion result.

4. Summary

In this article, we introduced how to encapsulate PHP's database operation function library, and demonstrated how to perform add, delete, modify, and query operations on the database. By encapsulating database operations, you can not only improve the readability and maintainability of your code, but also save development time. Therefore, in actual development, we can write corresponding encapsulation functions for different database operations according to specific needs to improve development efficiency and code quality.

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