What is Metadata?

Metadata is defined as the information that describes and explains data. It provides context with details such as the source, type, owner, and relationships to other data sets. So, it can help you understand the relevance of a particular data set and guide you on how to use it.

metadata

I have clicked a snapshot in the evening time recently which I have used as an example to explain what is metadata. As you can see there is an image at first and the later part provides information about the picture like at what time it was taken, which device was used to click the picture, the focal length, size of the image, etc.

What are the types of metadata?

Metadata can be classified into the following types:

1. Technical: This includes technical metadata such as row or column count, data type, schema, etc.
2. Governance: This includes governance terms, data classification, ownership information, etc.
3. Operational: This includes information on the flow of data such as dependencies, code, and runtime
4. Collaboration: This includes data-related comments, discussions, and issues
5. Quality: This includes quality metrics and measures, such as dataset status, freshness, tests run, and their statuses
6. Usage: This includes information on how much a dataset is used, such as view count, popularity, top users, and more.

Why is metadata important?
The right context for data is essential for understanding and putting it to use. Metadata helps you make data discoverable, accessible, trustworthy, and valuable.

Metadata helps summarize a set of other data and can include information such as:

1. How the data was created — the means.
2. When the data was created — the time and date.
3. Why the data was created — the purpose.
4. Who created the data — the author.
5. Where the data was created — the location.
6. How big the data is — the file size.

MetaData in WordPress

In WordPress, metadata is information about your posts, pages, users, comments, and other items on your site. For example, a post’s metadata would include information like the author, the publish date, the category and tags, and more.

On the web in general, metadata can also refer to information about web pages like the title and short description that appear in search results. Those are called meta tags, because they’re a type of HTML tag that add metadata to a page.

All the metadata on your site is stored in the WordPress database. Your theme is what determines which metadata is displayed on your site, and where and how it’s displayed.

The default metadata for posts includes the author, post date, and categories and tags. You can also add your own custom metadata.

WordPress uses descriptive metadata. What we define as data in WordPress and what can be defined as metadata is a little blurry, and doesn’t equate directly to what’s stored in the metadata tables. For example:

For posts, post_type is an example of metadata, but it’s stored in the wp_posts table
Taxonomy terms, categories and tags can also be loosely defined as metadata, but these are stored entirely separately, in their own database tables.
Post metadata such as custom fields and additional metadata added via plugins is stored in the wp_postmeta table, as you would expect.
So it’s easier to think of metadata in WordPress not according to the strict definition of the term, but as the data stored in the three metadata tables.

The Metadata Tables

WordPress uses three database tables for metadata:

1. wp_postmeta stores metadata about posts (including attachments, navigation menu items and revisions)
2. wp_commentmeta stores metadata about comments
3. wp_usermeta stores metadata about users

The metadata tables are all nearly identical in that they have just four fields:

ID is the ID of the post, user or comment the metadata relates to
Meta ID refers to the ID of the metadata record
Key is the meta key (which is often duplicated between different records)
Value is the meta value (which tends to be unique)