This is the code I am using to create a custom table named "prefix" + zillow--> where prefix is the wp table prefix for the site.


The actual function is given below-- it checks if such a table already exists along with assigned version number for that table(so that I can update /alter that table in a later version of this theme)--

function CreateTable() {
  //Database table versions
  $zillow_db_table_version= "1.0";
  $table_name = $wpdb->prefix . "zillow";

  $installed_ver = get_option( "zillow_db_table_version" );
  //Check if the table already exists and if the table is up to date, if not create it
  if($wpdb->get_var("SHOW TABLES LIKE '$table_name'") != $table_name || $installed_ver != $zillow_db_table_version ) {
    $sql = "CREATE TABLE " . $table_name .
    " (propertyid varchar(20) NOT NULL ,
    inserted_on date,
    UNIQUE KEY id (id) );";
    require_once(ABSPATH . 'wp-admin/includes/upgrade.php');
    update_option( "zillow_db_table_version", $zillow_db_table_version );
  //Add database table versions to options
  add_option("zillow_db_table_version", $zillow_db_table_version);


But the table is not getting created at all. What is wrong with the above code? I tried activating the theme using above code multiple times(after first activating a different theme and then activating this one) but no table is getting created (I check directly in the WP database list of tables ).

  • Have you tried adding global $wpdb; and turn on debugging.
    – Wyck
    Commented Jun 7, 2013 at 17:28

1 Answer 1


dbDelta is extremely picky. Looking at your code I'd say you've violated this rule:

You must put each field on its own line in your SQL statement

Two of your fields are sharing lines with parenthesis. I haven't tested that particular pattern but dbDelta is extremely picky.

I don't know if that space after NOT NULL will matter.

I doubt that checking for the existence of the table is necessary. Checking your option should be sufficient.

And finally, register_activation_hook is for plugins, not themes. There is no similar specialized theme activation hook that I am aware of. There are a number of work-arounds that have been suggested if you search this site for them.

  • what do you suggest i use in place of dbDelta? Also the code sample in my question bunched up the code together-- actually in the php code the fields are all on different rows (including the key at the end of sql for table definition).
    – Arvind
    Commented Jun 7, 2013 at 17:45
  • I don't suggest you use anything instead of dbDelta but you have to very, very careful with syntax. I think the primary answer is at the bottom though. You say in the title that you want to run this on theme activation but you are using a hook that runs on plugin activation.
    – s_ha_dum
    Commented Jun 7, 2013 at 17:49

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