In Drupal 7, all fields in the base table are known as properties, such as title, author_id, current_time_stamp, etc. All other fields, such as the image of the body and many others that you create, are stored in other tables. In fact, Drupal creates a separate table for each field in the database and saves the primary key of the package of objects (article, base page) in this field table as a foreign key. Basically, Drupal makes two tables for each field 1: for storing data (field_data_ [name_of_field]) and 2: for checking (field_revision_ [name_of_field]).
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