The Metadata API is a simple and standarized way for retrieving and manipulating metadata of various WordPress object types. Metadata for an object is a represented by a simple key-value pair. Objects may contain multiple metadata entries that share the same key and differ only in their value.
This function assumes that a dedicated MySQL table exists for the $meta_type you specify. Some desired $meta_types do not come with pre-installed WordPress tables, and so they must be created manually.
Assuming a prefix of
wp_, WordPress's included meta tables are:
To store data for meta types not included in the above table list, a new table needs to be created. All meta tables require four columns...