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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()?

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

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

   Uploaded binary files. Large API response archives used once per month. Small settings required on most requests. Every option, regardless of size or usage.
   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 expiration permanently stores the value in wp_posts. The value is guaranteed to exist until the exact expiration second. The value will not be returned after that maximum lifetime, but it may disappear earlier. Expiration is ignored when an object cache is active.
   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?

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

   It bypasses serialization It always writes to wp_options Without a persistent object-cache backend, values usually last only for the request It cannot store arrays
   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 creates a custom table It silently discards the value 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' 'posts_per_page' => 0 'fields' => 'ids' 'output' => 'minimal'
   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 is traffic-triggered and may run later than scheduled It runs only from wp-admin It is guaranteed to run at the exact second
    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 Only sticky posts One page of IDs
    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?

    suppress_sticky ignore_sticky_posts no_found_rows sticky_order
    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?

    term_filter tax_query meta_query taxonomy_where
    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 Concatenate raw input Use esc_html() Escape wildcards with esc_like(), add wildcards, then pass it to prepare()
    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 the database failed False is converted to an empty post False means missing or expired, so a stored false value is ambiguous 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 One custom table per setting A post for every scalar A transient with no expiration
    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 control rewrite priority To create SQL indexes To namespace keys belonging to different components 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?

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

    Fast stale data may still be wrong.