Creating terms vs custom post meta to save data?

Question

I am making a news aggregation site on wordpress. I've to save domains of source urls somewhere. Sometimes source url could be same for multiple posts. So I'm confused how should I save the data.

I've two options

1. Creating custom taxonomy and then save domain as terms.
2. Create custom post meta for each post.

By using custom post meta, every post will get its separate meta data entry. On the other hand once the domain name is saved as term it can be added to any post just like tags. In future I'll need post ids having same domain name. Also I know my news aggregation site will grow into something mega. While keeping these two methods to save data (term/post meta) in mind I want my site speedy and database smaller in size.

So which method should I use. I want to know expert opinion about efficiency, speed and smart data storage techniques.

Answer 1

First option:

Creating custom taxonomy and then save domain as terms.

• Basically "taxonomy" is a grouping mechanism. In your requiremnt there would not be too many CPTs are of same taxonomy.
• For Taxonomy, you have to maintain 3 tables, wp_terms, wp_term_taxonomy and wp_term_relationships.
• So, while creating a NEWS (your CPT), you will fire queries on these 3 tables.
• While fetching domain(taxonomy) WordPress will make joins on these tables.

About:

1) Efficiency: You have to create custom taxonomy, assign it to post.

2) Speed: More joins, less speed.

3) Storage: Entry in 3 tables. ( 3 rows ).

Second option:

Create custom post meta for each post.

• For custom post meta, you need to code to show/save meta on an edit page.

About:

1) Efficiency: You need to add data in post meta field, that's it.

2) Speed: Normally, WordPress fires query by joining 2 tables, wp_posts and wp_postmeta. No more joins, just specify meta key name.

3) Storage: Only one row in wp_postmeta table.

In future if you want to get all post IDs, just simple query on wp_postmeta table.