What is the name of the procedure opposite to partitioning data by tables through identifiers?

The procedure opposite to splitting data into tables via identifiers (i.e., normalization) is called denormalization.

Denormalization is the process of combining data from multiple tables into one or reducing the number of relationships between tables to improve query performance, simplify the structure, or achieve other goals. In PHP and other languages, this can manifest as combining data during retrieval or storing redundant information to speed up access.

Example: instead of storing a user's address in a separate table, their data can be included directly in the users table.