A solution to the database design of WordPress

About the database design of WordPress
Read an article on the Internet that the WordPress data table using the form of key-value pairs, so that the design of fewer fields, faster query. is the database query field less quickly than the number of fewer bars? And it's this key-value pair design, sometimes an article has 4, 5 key-value pairs, then this table is very easy to bar number will be very much, will not affect performance.
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The associative array of PHP is the form of a key-value pair, which is the specific implementation of the hash table
Key-value pairs are specific implementations of metadata (metadata)
Widely used in NoSQL databases
SQL database is a relational database, so the idea of implementing metadata in it is more difficult.

Simulation of NoSQL behavior in SQL, due to the lack of internal support of the database system, but only with the script to implement
Obviously, efficiency is low.
It's like an ORM in some framework, which is clearly a matter of writing a SQL command directly.
It's going to be torn apart. To pass the parameters through multiple methods and then assemble them into SQL instructions
Can you say that he will be more efficient? It's just that it looks like a self-deception.

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