When users update their profile information, it is important to ensure that certain fields, such as mobile numbers, remain unique across all user accounts. This article explains how to prevent users from updating their profile with a mobile number that is already assigned to another account.<\/p>\n
Assume you have a table named When a user updates their profile, you need to:<\/p>\n The following example checks whether the mobile number already exists for another user before performing the update.<\/p>\n The Example using MySQLi:<\/p>\nls_users<\/code><\/strong> with the following columns:<\/p>\n\n
email<\/code><\/li>\nphone<\/code><\/li>\n<\/ul>\n\n
Example Implementation<\/h2>\n
<?php\n\n$email = \"example@gmail.com\";\n$newPhone = \"1234567890\";\n\n$query = mysql_query(\"\n SELECT phone\n FROM ls_users\n WHERE email NOT IN ('$email')\n AND phone = '$newPhone'\n\");\n\nif (mysql_num_rows($query) > 0) {\n echo \"This mobile number is already registered. Please use another number.\";\n} else {\n mysql_query(\"\n UPDATE ls_users\n SET phone = '$newPhone'\n WHERE email = '$email'\n \");\n \n echo \"Profile updated successfully.\";\n}\n\n?>\n<\/code><\/pre>\nHow It Works<\/h2>\n
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SELECT<\/code> query checks whether the new mobile number already exists for any user other than the currently logged-in user.<\/li>\nRecommended Modern Approach (MySQLi)<\/h2>\n
mysql_*<\/code> functions used in the example above are deprecated and removed in newer PHP versions. For modern applications, use MySQLi<\/strong> or PDO<\/strong> with prepared statements.<\/p>\n$stmt = $conn->prepare(\"\n SELECT id\n FROM ls_users\n WHERE email != ?\n AND phone = ?\n\");\n\n$stmt->bind_param(\"ss\", $email, $newPhone);\n$stmt->execute();\n$result = $stmt->get_result();\n\nif ($result->num_rows > 0) {\n echo \"This mobile number is already registered.\";\n} else {\n $update = $conn->prepare(\"\n UPDATE ls_users\n SET phone = ?\n WHERE email = ?\n \");\n\n $update->bind_param(\"ss\", $newPhone, $email);\n $update->execute();\n\n echo \"Profile updated successfully.\";\n}\n<\/code><\/pre>\nBest Practice<\/h2>\n