install.php

<?php
require_once "./db.php";
try {
	$conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
	// set the PDO error mode to exception
	$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

	echo "start sql...";
	// sql to create table
	$sql .= "DROP TABLE IF EXISTS `ejson_content`;";
	$sql .= "CREATE TABLE `ejson_content` ( `id` int(11) NOT NULL COMMENT 'id', `json` text NOT NULL COMMENT 'json value') ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;";
	$sql .= "INSERT INTO `ejson_content` (`id`, `json`) VALUES (1, '{}'), (2, 'a3fa');";
	$sql .= "ALTER TABLE `ejson_content` ADD PRIMARY KEY (`id`);";
	$sql .= "ALTER TABLE `ejson_content` MODIFY `id` int(11) NOT NULL AUTO_INCREMENT COMMENT 'id', AUTO_INCREMENT=3; COMMIT;";

	$conn->exec($sql);
	echo "<br>";
	echo "<br>";
	echo "Mysql data install successfully!";
	echo "<br>";
	echo "<br>";
	echo "Rename install.php or delete it.";
}
catch(PDOException $e) {
	echo "Error: " . $e->getMessage();
}
$conn = null;
?>