wp-database

Use when a WordPress plugin needs a custom database table — creating with dbDelta (strict SQL format: two spaces before PRIMARY KEY, no trailing comma), writing versioned upgrade routines with version_compare and register_activation_hook, querying with $wpdb prepared statements (prepare, insert, update, delete, get_row, get_results, get_var), debugging with $wpdb->last_error or SAVEQUERIES, schema migrations between plugin versions, uninstall cleanup, multisite table handling with switch_to_blog / get_sites, or seeding test/preview data into custom tables. Triggers: \"create a custom table\", \"dbDelta not working\", \"dbDelta not creating my table\", \"write a migration\", \"wpdb query\", \"wpdb prepare\", \"slow query on my custom table\", \"upgrade my database schema\", \"add a column to my table\", \"seed test data\", \"how do I store this in a custom table\", \"database upgrade routine\", \"table not being created on activation\", \"prepare placeholder wrong\", \"last_error is empty after query\", \"SAVEQUERIES debug\", \"version_compare for db upgrade\", \"register_activation_hook table\", \"wpdb prefix table name\", \"uninstall drops table\", \"multisite per-site table\", \"charset_collate missing\". Not for: WordPress options API or post meta — use those when a custom table is not needed.