Use array_combine to build database field mapping relationship

M66 2025-05-12

In PHP, the array_combine function is a very useful function that combines two arrays into an associative array. When developing database applications, it is often necessary to map the database field names to model or other forms of variable names. At this time, the array_combine function can be used to help us complete this task.

1. Introduction to array_combine function

The array_combine function accepts two arrays as parameters, the first array is used as keys to the associative array, and the second array is used as values. The function combines the elements in these two arrays one by one into a new associative array.

grammar:

 array_combine(array $keys, array $values): array|false

$keys : The key used to build an associative array.
$values : The value used to build the associative array.

This function returns a new associative array. If the array length is inconsistent, false is returned.

2. Example: Building a database field mapping relationship

In actual development, we often need to map database field names to corresponding variables or model properties. Suppose our database has a user table, which includes fields such as user_id , user_name , email , etc. We can use the array_combine function to map these database fields into variable names in the array.

Sample code:

 <?php
// Database field name
$fields = ['user_id', 'user_name', 'email'];

// Corresponding model properties
$modelAttributes = ['id', 'name', 'emailAddress'];

// use array_combine Building a field mapping relationship
$fieldMap = array_combine($fields, $modelAttributes);

// Output result
print_r($fieldMap);
?>

Output:

 Array
(
    [user_id] => id
    [user_name] => name
    [email] => emailAddress
)

In this example, the $fields array contains the field names in the database, while the $modelAttributes array contains the corresponding model attributes. Through the array_combine function, we successfully combine these two arrays into an associative array $fieldMap , which defines the mapping relationship between field names and attribute names.

3. Application in actual projects

Scenario 1: Map database fields to model properties

During a database operation, we usually get the data through the field name and assign the data to the corresponding attributes of the model. For easy operation, the mapping relationship between field names and model attributes can be set in advance.

 <?php
// Suppose we get a user record from the database
$userData = [
    'user_id' => 1,
    'user_name' => 'John Doe',
    'email' => 'johndoe@m66.net'
];

// Mapping relationship between database fields and model attributes
$fieldMap = array_combine(['user_id', 'user_name', 'email'], ['id', 'name', 'emailAddress']);

// use映射关系赋值到模型属性
$userModel = new UserModel();
foreach ($fieldMap as $dbField => $modelField) {
    if (isset($userData[$dbField])) {
        $userModel->$modelField = $userData[$dbField];
    }
}

print_r($userModel);
?>

In this example, we get a user record from the database (array $userData ). Next, we use array_combine to create a mapping relationship between the field and the model attributes $fieldMap . Then through a loop, we assign the data in the database to the corresponding attribute of $userModel according to the mapping relationship.

Scenario 2: Build query conditions

When building a query, we sometimes need to convert the model attributes to the database field name. For example, a user submits a query condition where the field name is a model property, which we need to convert to the field name of the database in order to query.

 <?php
// Mapping relationship between model attributes and database fields
$fieldMap = array_combine(['user_id', 'user_name', 'email'], ['id', 'name', 'emailAddress']);

// Query conditions entered by the user
$userInput = [
    'name' => 'John Doe',
    'emailAddress' => 'johndoe@m66.net'
];

// 将模型属性转换为Database field name
$queryConditions = [];
foreach ($userInput as $modelField => $value) {
    if (in_array($modelField, $fieldMap)) {
        $dbField = array_search($modelField, $fieldMap);
        $queryConditions[$dbField] = $value;
    }
}

// Output database field query conditions
print_r($queryConditions);
?>

Output:

 Array
(
    [user_name] => John Doe
    [email] => johndoe@m66.net
)

Through array_combine , we convert the model attributes entered by the user into the database field name to form the final query condition $queryConditions .

4. Summary

Using the array_combine function, it is easy to establish a mapping relationship between database fields and model properties. This not only improves the readability and maintainability of the code, but also helps us to handle mapping transformations between databases and models more flexibly in development.

Through the examples in this article, I believe you have mastered how to use array_combine to build the mapping relationship between database fields and model properties and apply it in actual projects.

array_combine