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How to Analyze Database Field Constraints from the Return Value of mysqli_result::fetch_field?

gitbox 2025-09-12 
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</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<h1>How to Analyze Database Field Constraints from the Return Value of mysqli_result::fetch_field?</h1>"</span></span><span>;
<p></span>echo <span><span class="hljs-string">"<p>In PHP, the <code>mysqli
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Similarly, you can check if the field is a primary key or auto-increment:

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<br>
if ($field->flags & MYSQLI_PRI_KEY_FLAG) {<br>
echo "The field is a primary key";<br>
}<br>
if ($field->flags & MYSQLI_AUTO_INCREMENT_FLAG) {<br>
echo "The field is auto-incremented";<br>
}<br>
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3. Conclusion

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By using the mysqli_result::fetch_field method, we can easily retrieve basic information about the field, such as its name, type, and length. Through bitwise operations on the flags attribute, we can also analyze the field's constraints, such as NOT NULL, primary key, uniqueness, auto-increment, etc. This allows dynamic handling of database table structures in PHP code.

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