> "components" are "tables"

No, components are columns. Each entity is a row in a table and an archetype (the set of all entities with the same components) is a table.

In ECS it's usual to store components together, this corresponds to columnar storage in database terms (or equivalently, it's as if data were in sixth normal form [0]). However in some systems you can opt to store a more traditional row-based column.

[0] https://en.wikipedia.org/wiki/Database_normalization#Satisfy...