PDO creating database and tables - php

Question

I'm currently struggling with an assignment. I am to create a PHP script that will create a database and all the tables for that database. I have been able to cobble together the script to create the database itself from reading here and W3Schools, however I am stumped as to how to have the same script create tables on that new database. Here's what I have to create a new database:
<?php
$servername = "localhost";
$username = "root";
$password = "mysql";
try {
$conn = new PDO("mysql:host=$servername", $username, $password);
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$sql = "CREATE DATABASE IF NOT EXISTS musicDB";
$conn->exec($sql);
echo "DB created successfully";
}
catch(PDOException $e)
{
echo $sql . "<br>" . $e->getMessage();
}
$conn = null;
?>
I tried to follow on that to then create tables with this:
<?php
$servername = "localhost";
$username = "root";
$password = "mysql";
try {
$conn = new PDO("mysql:host=$servername", $username, $password);
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$sql = "CREATE DATABASE IF NOT EXISTS musicDB";
$sql = "use musicDB";
$sql = "CREATE TABLE IF NOT EXISTS ARTISTS (
ID int(11) AUTO_INCREMENT PRIMARY KEY,
artistname varchar(30) NOT NULL)";
$conn->exec($sql);
echo "DB created successfully";
}
catch(PDOException $e)
{
echo $sql . "<br>" . $e->getMessage();
}
$conn = null;
?>
However that is not working and I get the following error: CREATE TABLE IF NOT EXISTS ARTISTS ( ID int(11) AUTO_INCREMENT PRIMARY KEY, artistname varchar(30) NOT NULL)
SQLSTATE[3D000]: Invalid catalog name: 1046 No database selected
Basically, how do I tell the script to use the newly created table and then create tables for it? And I know the username and password are showing but this is running on my laptop and will never be anywhere so I'm not worried.

Answer 1

You're only executing the last statement. You keep assigning to $sql, but not executing those statements.
try {
$conn = new PDO("mysql:host=$servername", $username, $password);
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$sql = "CREATE DATABASE IF NOT EXISTS musicDB";
$conn->exec($sql);
$sql = "use musicDB";
$conn->exec($sql);
$sql = "CREATE TABLE IF NOT EXISTS ARTISTS (
ID int(11) AUTO_INCREMENT PRIMARY KEY,
artistname varchar(30) NOT NULL)";
$conn->exec($sql);
echo "DB created successfully";
}
catch(PDOException $e)
{
echo $sql . "<br>" . $e->getMessage();
}

Answer 2

Instead, try wrapping all these statements in a procedure and call that from your code behind like
create procedure usp_createDB
as
begin
CREATE DATABASE IF NOT EXISTS musicDB;
use musicDB;
CREATE TABLE IF NOT EXISTS ARTISTS (
ID int(11) AUTO_INCREMENT PRIMARY KEY,
artistname varchar(30) NOT NULL);
end