How to represent database schemas?

What is the best way to visually share and communicate database schemas?

This is my new user name and profile picture on Quora! 

I chose an image from my laptop at random

I am Math Troll. They got rid of the 'real names policy' in 2018 or so.

An Entity Relationship Diagram (ERD) will capture:

• the contents of each table,
• the relationships between tables: primary keys, foreign keys,
• some exogenous information such as input data source.

I've become fond of Toad for Oracle as a tool for visually describing existing database schema. Toad could be described as an applications development environment, but it has an ERD creation function, which can be used to generate a nicely portable diagram in a choice of formats, certainly XLS and PNG, and possibly PDF.

In addition to the ERD, it is helpful to have a corresponding data dictionary in document form that lists, by table, the fields (and what they represent as descriptive naming isn't usually an option when field names are restricted to only 8 characters or similarly few bytes), field type and length. Toad generates such a document.

For a quick layout of something conceptual, try using MS Visio, or even MS Excel.