更新和插入数组等

Question

I have a MySQL db called table_music Here I store artist, song,... this is something I will update from a form I have on a page.

Now I want to add genres to this form as well, so I made a table called song_genre Here I have song_genre_id, song_id, genre_id

In my form I list the title of song from my table_music Then I have fields where I can update the composer, length, year, and so on. And there is also a checkbox list called genre from my song_genre table with all the genres sorted alphabetically. I have these in a different table, since I might want to add genres later.

But I don't know how to insert these checked genres into my song_genre table. I've never used arrays before, so I'm lost here.

First I want to UPDATE my table_music and that is working fine. Then I want to INSERT INTO my new table (song_genre) so I get the genre and the song_id in here.

I think that's the right way to do it, so I am able to change the genre later or add or remove one genre if I need that as well one day.

I tried the following: but it doesn't seem to work:

foreach(echo $row_rs_genres['genre_id'] as $checked_value)
{
   $query = "INSERT INTO song_genre (genre_id, song_id) VALUES ('$checked_value',    $_POST['song_id'])"; 
   $result = mysql_query($query) or die ("Unable to execute query: " . mysql_error());

}

Answer 1

Remove the echo:

foreach($row_rs_genres['genre_id'] as $checked_value)

And you need to enclose the $_POST in curly brackets:

"INSERT INTO song_genre (genre_id, song_id) VALUES ('$checked_value', {$_POST['song_id']})"

Or break out of the string:

"INSERT INTO song_genre (genre_id, song_id) VALUES ('" . $checked_value . "', " . $_POST['song_id'] . ")"

Although you're susceptible to SQL injection here. You should escape your input or switch to prepared statements.