There is a class variable that stores the last error string – $wpdb->last_error. By the looks of the way $wpdb is coded, if the query succeeds, $wpdb->last_error will be an empty string, if it fails, it will be the error string returned by MySQL. So something like this would do the trick. $result = $wpdb->get_results(“SELECT … Read more
You can execute arbitrary SQL statements with wpdb::query(), including Data Definition Statements, e.g. function create_index () { global $wpdb ; $sql = “CREATE INDEX my_index ON {$wpdb->prefix}my_table (my_column)” ; $wpdb->query ($sql) ; return ; } Note: Because $wpdb->query() can execute arbitrary SQL, if the statement you pass to it contains ANY user input, then you … Read more
It’s in the table postmeta with the meta_key of _wp_old_slug If you wanted to clear all of the old slugs you could use this: DELETE FROM wp_postmeta WHERE meta_key = ‘_wp_old_slug’;
$wpdb->insert() method returns false if the row could not be inserted. Otherwise, it returns the number of affected rows (which will always be 1). You can turn error echoing on and off with the show_errors and hide_errors, respectively. <?php $wpdb->show_errors(); ?> <?php $wpdb->hide_errors(); ?> You can also print the error (if any) generated by the … Read more
I rarely disagree with otherwise knowledgeable users, but in this case I can’t help it. In my opinion calling the usage of non-core database tables bad practice per se is just simply wrong. The choice of whether to go with core tables or add your own depends on several factors. A query’s execution time depends … Read more
According WP database structure, ID in wp_users is Bigint(20) UNSIGNED, so you could “theoretically” add 18446744073709551615 users. http://dev.mysql.com/doc/refman/4.1/en/integer-types.html
I have personally worked with Percona Server and MySQL, not with MariaDB as of yet. Percona provides support for MariaDB, Drizzle, Amazon RDS, and other MySQL products. I learned at Percona Live NYC that Percona gets the latest version of MySQL and injects 30,000 lines of C/C++ that is unique to its Performance Enhancements. MySQL … Read more
Here are two possible solutions, both of these are actually generic MySQL version control tools but can be adapted to your workflow: dbv.php This tool creates “migrations”, which are basically SQL scripts, from the changes detected on the database. These scripts are stored in a local directory and thus can be commited to your current … Read more
One thought – when I go to www.example.com/staging/wp-admin it automatically redirects me to www.example.com/wp-admin Could the redirect from staging.example.com to example.com/staging be conflicting with the existing install? UPDATE: looks like it could be related to .htaccess issues and complicated domain references in the database From the WP Codex: Moving WordPress Multisite Multisite is far more … Read more
There are two defines in wp-config.php of WordPress website: define(‘DB_CHARSET’, ‘utf8’); define(‘DB_COLLATE’, ”); There are several things which are most commonly misunderstood. Names of constants in those defines, might suggest that they are related to the database itself. They are not. They are related to tables within the database. Database creation is totally independent from … Read more