Checking if a term exists in WordPress using term_exists

The term_exists function is a part of the WordPress core function library. Its primary purpose is to check if a particular term exists within a specific taxonomy in the WordPress database. This function can be beneficial in scenarios where it’s necessary to verify the existence of a term before performing an operation on it. For instance, it can be used to prevent duplication of terms in a taxonomy or to ensure that a term is available for a specific task.

When the term_exists function is executed, it returns an array containing the term’s ID and the term_taxonomy_id if the term exists. If the term does not exist, the function will return 0 or null. This return value can be used to make decisions in the code logic based on the existence of the term.

In a broader context, the term_exists function contributes to the overall flexibility and robustness of content management in WordPress. It provides a way to interact with the taxonomy system of WordPress, helping developers to manage terms more effectively.

Parameters of the term_exists Function

The term_exists function in WordPress is designed to accept three parameters. These parameters are outlined as follows:

  • $term (int|string): This is a mandatory parameter. It represents the term to be checked. This parameter can take the form of term ID, slug, or name.
  • $taxonomy (string): This parameter is optional. Its default value is an empty string (”). It represents the taxonomy name to be used.
  • $parent_term (int): This is another optional parameter. Its default value is null. This parameter is used to specify the ID of the parent term under which the search for existence is to be confined.

Return Value of the term_exists Function

The term_exists function in WordPress has a mixed return value. The specifics of what it returns are as follows:

When the term does not exist, the function will return null. If no taxonomy is specified and the term ID exists, the function will return the term ID. If the taxonomy is specified and the pairing exists, the function will return an array of the term ID and the term taxonomy ID. If term ID 0 is passed to the function, it will return 0.

If the function does not accept any parameters, it will be clearly stated in the function’s description.

Examples

How to Check if a Category Exists

The following code snippet checks if a category with the name ‘News’ exists.

$term = term_exists('News', 'category');
if ($term !== 0 && $term !== null) {
 echo "<p>Category 'News' exists</p>";
} else {
 echo "<p>Category 'News' does not exist</p>";
}

How to Check if a Tag Exists

This code snippet checks if a tag with the slug ‘my-tag’ exists.

$term = term_exists('my-tag', 'post_tag');
if ($term !== 0 && $term !== null) {
 echo "<p>Tag 'my-tag' exists</p>";
} else {
 echo "<p>Tag 'my-tag' does not exist</p>";
}

How to Check if a Term Exists in a Custom Taxonomy

This code snippet checks if a term with the name ‘My Term’ exists in a custom taxonomy ‘my_taxonomy’.

$term = term_exists('My Term', 'my_taxonomy');
if ($term !== 0 && $term !== null) {
 echo "<p>Term 'My Term' exists in 'my_taxonomy'</p>";
} else {
 echo "<p>Term 'My Term' does not exist in 'my_taxonomy'</p>";
}

In each of these examples, the term_exists function returns either an array of term data, or 0 or null if the term does not exist. The if statement checks if the result is not 0 and not null, which means the term exists. If the term exists, a message is echoed out. If not, a different message is echoed out.

Conclusion

In summary, the term_exists function in WordPress is a tool for checking the existence of a term in a taxonomy. It is primarily used to prevent the creation of duplicate terms in the database, thereby ensuring data integrity and consistency. This function can be employed in diverse contexts, such as plugin development or theme customization, where there is a need to verify the existence of a term before performing an operation. Thus, term_exists plays a significant role in maintaining the efficiency and effectiveness of database operations within the WordPress ecosystem.

Related WordPress Functions

in WordPress Functions