WordPress Plugin Development

4 Methods to  save Plugin data in DB:

1. Table: wp_{multisiteID}_options
   Use the WordPress "option" mechanism (described below). This method is appropriate for storing relatively small amounts of relatively static, named pieces of data -- the type of data you'd expect the site owner to enter when first setting up the Plugin, and rarely change thereafter.
2. Table: wp_{multisiteID}_postmeta
   Post Meta (a.k.a. Custom Fields). Appropriate for data associated with individual posts, pages, or attachments. See post_meta Function Examples, add_post_meta(), and related functions.
3. Custom Taxonomy. For classifying posts or other objects like users and comments and/or for a user-editable name/value list of data consider using a Custom Taxonomy, especially when you want to access all posts/objects associated with a given taxonomy term. See Custom Taxonomies.
4. Create a new, custom database table. This method is appropriate for data not associated with individual posts, pages, attachments, or comments -- the type of data that will grow as time goes on, and that doesn't have individual names. See Creating Tables with Plugins for information on how to do this.