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1. 1. What should be called after a secondary loop that uses WP_Query::the_post()?

   $query = new WP_Query( $args );
   while ( $query->have_posts() ) {
       $query->the_post();
       the_title();
   }

   What should be called after a secondary loop that uses WP_Query::the_post()?

   flush_rewrite_rules() wp_reset_query_vars() wp_reset_postdata() Nothing: WP_Query always restores $post automatically.
   Hint

   The secondary loop changed the global $post variable.

2. 2. How should dynamic values be included in a custom SQL query with $wpdb?

   The query contains values supplied at runtime.

   How should dynamic values be included in a custom SQL query with $wpdb?

   Use $wpdb->prepare() with typed placeholders. Concatenate the raw values after addslashes(). Base64-encode every value before querying. Use esc_html() before concatenating the SQL.
   Hint

   Do not concatenate untrusted values into the SQL string.

3. 3. Which values are good candidates for autoloaded options?

   Think about both access frequency and total payload size.

   Which values are good candidates for autoloaded options?

   Every option, regardless of size or usage. Large API response archives used once per month. Small settings required on most requests. Uploaded binary files.
   Hint

   Autoloaded options are loaded on many requests.

4. 4. What guarantee does a transient expiration provide?

   Consider external object caches as well as the database implementation.

   What guarantee does a transient expiration provide?

   The value will not be returned after that maximum lifetime, but it may disappear earlier. Expiration is ignored when an object cache is active. The expiration permanently stores the value in wp_posts. The value is guaranteed to exist until the exact expiration second.
   Hint

   An expiration is a maximum lifetime, not a minimum lifetime.

5. 5. What does relation control in a WP_Query meta_query?

   The query contains more than one metadata condition.

   What does relation control in a WP_Query meta_query?

   The number of posts returned per page. Whether the metadata clauses are combined with AND or OR logic. The post type rewrite slug. The SQL table prefix used by the query.
   Hint

   Think of boolean logic between clauses.

6. 6. When can no_found_rows improve a WP_Query?

   When can no_found_rows improve a WP_Query?

   When pagination totals are not needed When SQL must return no posts When meta queries are used Only in the admin area
   Hint

   Do you need max_num_pages?

7. 7. What is the main limitation of relying on wp_cache_set() for long-term persistence?

   What is the main limitation of relying on wp_cache_set() for long-term persistence?

   Without a persistent object-cache backend, values usually last only for the request It cannot store arrays It always writes to wp_options It bypasses serialization
   Hint

   The default object cache is request-scoped.

8. 8. What does update_post_meta() do when the meta key does not yet exist?

   What does update_post_meta() do when the meta key does not yet exist?

   It adds the metadata It silently discards the value It creates a custom table It throws an exception
   Hint

   The function supports both creation and update.

9. 9. Which WP_Query argument can reduce memory usage when only post IDs are needed?

   Which WP_Query argument can reduce memory usage when only post IDs are needed?

   'cache_results' => 'titles' 'fields' => 'ids' 'output' => 'minimal' 'posts_per_page' => 0
   Hint

   Request only the shape of data you need.

10. 10. What should a developer remember about WP-Cron timing?

    What should a developer remember about WP-Cron timing?

    It requires one PHP process per event It runs only from wp-admin It is guaranteed to run at the exact second It is traffic-triggered and may run later than scheduled
    Hint

    It is not the operating system cron daemon.

11. 11. What does posts_per_page => -1 request from WP_Query?

    What does posts_per_page => -1 request from WP_Query?

    All matching posts without pagination No posts One page of IDs Only sticky posts
    Hint

    Use carefully on large datasets.

12. 12. Which WP_Query argument prevents sticky posts from being promoted?

    Which WP_Query argument prevents sticky posts from being promoted?

    ignore_sticky_posts suppress_sticky sticky_order no_found_rows
    Hint

    It does not exclude sticky posts from matching.

13. 13. Which WP_Query argument filters posts by taxonomy terms?

    Which WP_Query argument filters posts by taxonomy terms?

    meta_query taxonomy_where term_filter tax_query
    Hint

    Metadata and taxonomy data use different query arguments.

14. 14. How should a LIKE search value be prepared with $wpdb?

    How should a LIKE search value be prepared with $wpdb?

    Base64 encode it Escape wildcards with esc_like(), add wildcards, then pass it to prepare() Use esc_html() Concatenate raw input
    Hint

    LIKE escaping and SQL placeholders solve different problems.

15. 15. Why must code treat get_transient() returning false carefully?

    Why must code treat get_transient() returning false carefully?

    False means missing or expired, so a stored false value is ambiguous False is converted to an empty post False means the database failed False means the user logged out
    Hint

    Avoid caching a literal false when you must distinguish it.

16. 16. What is often more efficient for a small related settings group?

    What is often more efficient for a small related settings group?

    One structured option loaded and updated together A transient with no expiration A post for every scalar One custom table per setting
    Hint

    Keep unrelated or very large values separate.

17. 17. Why use cache groups with wp_cache_get() and wp_cache_set()?

    Why use cache groups with wp_cache_get() and wp_cache_set()?

    To namespace keys belonging to different components To create SQL indexes To control rewrite priority To assign user roles
    Hint

    A key may be common, such as count.

18. 18. What is the hard part of caching a database query in a transient?

    What is the hard part of caching a database query in a transient?

    Serializing arrays Calling get_transient() Choosing a PHP variable name Invalidating or refreshing it when the underlying data changes
    Hint

    Fast stale data may still be wrong.