Why do database examples sometimes finish with an add_option call?

It’s adding a record in the database of which version of the database is in use. This can be used in future to determine whether or not the database structure on a given site needs to be updated if the plugin changes its database structure in a future version.

You’ve likely seen this yourself when updating WordPress and it tells you you need to upgrade the database. Whenever this happens WordPress records which version of the database is in use so that when WordPress is updated it can see whether an upgrade is required.

Related Posts:

  1. What is the difference between an ORM and an ODM?
  2. Rename a table in MySQL
  3. How should I tackle –secure-file-priv in MySQL?
  4. Can’t connect to MySQL server on ‘127.0.0.1’ (10061) (2003)
  5. Keeping WP database synced across multiple developers using git
  6. Staging sites, how do you manage synchronising updates in the DB?
  7. How to get the post publish date outside the loop?
  8. Using transients in conjunction with memcached
  9. How to define composite keys with dbDelta()
  10. Has parent field in the table wp_term_taxonomy has term_id or term_taxonomy_id
  11. Forcing nickname as display_name in custom edit profile template
  12. Connect forms in WP to external database
  13. Hook into $wpdb
  14. Export WP database for import using WP-CLI on Vagrant Box
  15. How to get site URL if database is disconnected?
  16. Is it wise to delete post revisions and autosaves from database?
  17. Showing content from another wordpress installation database in the page template loop?
  18. Multiple WP install with same users database
  19. Dynamic data in `wp_register_script` needed
  20. Why is $wpdb->get_results failing on certain tables but not others (which have data)?
  21. Using two different DB users on one WP install
  22. Usage of Direct Database Call Without Caching Error
  23. Can I transfer a mysql database to another site?
  24. How to verify password outside WordPress?
  25. Weird issue with database migration and SSL links
  26. Backup another database with BackUpWordPress plugin [closed]
  27. Easiest Way to Authenticate WP Users Using an External DB?
  28. How to use a different database to list and manage comments in the backend
  29. How do I properly update the WordPress database password?
  30. wpdb_prepare with multiple or condition
  31. $wpdb->insert is not working
  32. WordPress Install and Database on separate hosting?
  33. Moving a site from a temporary domain to the live domain [duplicate]
  34. Error establishing a database connection on Installation
  35. What is this in my tables
  36. Why is it that not all users have a ‘session_tokens’ meta_key record in the usermeta table?
  37. How do I find out the full path of a page’s template?
  38. WP get stuck with a query on MySQL when the site is resumed
  39. Use mulitple usernames?
  40. Routine to convert custom post meta from old to new value
  41. “The link you followed has expired” & “Error while saving” messages when adding new post
  42. Trying to change database tables storage engine to innodb gives error “invalid default value for ‘post_date'”
  43. database connection [closed]
  44. sanitize POST arrays
  45. WP character encoding error after sharing post on Facebook �
  46. Sending data with multi step form to wp database
  47. Able to use all admin pages but in the frontend there is a “Error establishing a database connection”-Error
  48. WordPress query is not returning proper results
  49. Undefined Variable: mysqli error when connecting to database
  50. Localhost to Staging to Development Dynamic WP-CONFIG
  51. Selectively restoring original posts from a compromised site to a freshly installed WordPress database
  52. can we add extra table or column in wordpress for adding our data
  53. Which data is written and stored in the database when read-only (non-posting, non-commenting) users visit the site?
  54. Is it possible to have more than 1 MySQL database in my WordPress blog?
  55. How and where is wordpress adding mySQL content to database?
  56. restore a db after bad backup
  57. Best practice to import user base (subscribers) from one website to another?
  58. Some weird users in database
  59. cannot connect database
  60. How to delete a particular row in a database table
  61. Location of image metadata on my server
  62. How to create more than one new wpdb object?
  63. Connecting to wordpress database in my application [closed]
  64. Is it good practice to import/export a blog to test a redesign?
  65. Getting value from database table depending on field value
  66. Getting “Error Establishing a Database Connection” on localhost in new Mac OSX Lion environment
  67. Secure way to use name_save_pre?
  68. wpdb->insert not inserting first variable
  69. Database tables for sports betting integrated in WordPress
  70. change the year on all of my custom post types?
  71. WordPress keeps redirecting to localhost
  72. get value from ‘terms’ table
  73. custom tables in wordpress Database? (can i just create them with sql?)
  74. New installation fatal error in 5.9.3 at edit or create entry
  75. Storing transients giving database error
  76. I want to replicate a wordpress website over multiple servers
  77. Displaying requested data from a the database in wordpress
  78. Accidently changed the GUID
  79. Is there anyway to split posts to different databases?
  80. wp-cli + valet: “Error establishing a database connection”
  81. local wordpress broke after changing URL
  82. Unable to login to a https website via the app after changing from http
  83. Is it safe to add INDEX to a column in WordPress database?
  84. Restore Old Database Over Newer WP & Plugin Files
  85. Not sure what to do next to optimize
  86. Database structure for thousands of posts
  87. How do I find out from my database what version of WordPress I need?
  88. How to create a database table?
  89. $wpdb not working
  90. Accessing content from third party as native posts in WordPress
  91. Extracted CSV as Array for Custom Query Loop
  92. Hang Up Followed By Can’t select database
  93. Database error after importing WordPress
  94. One WP Database outside localhost and two connections
  95. Fetch data from another site, but the same database
  96. Every time I update or install a plugin I get “Error Establishing a Database Connection in WordPress”
  97. Create hundreds of users with just ID in phpMyAdmin
  98. Upload wordpress from localhost to 000webhost
  99. Cant Connect to Database
  100. WordPress database connection failed, while mysql client is working [closed]