Gera Tools

Data Dictionary Builder

Document database fields with names, types, descriptions, and constraints

Builds a database data dictionary with field name, data type, nullable flag, default value, description, and validation rules per column — rendered as a clean Markdown table you can copy into docs.

What is a data dictionary?

A data dictionary is reference documentation describing each field in a database — its name, type, constraints, and meaning. It helps engineers and analysts use a schema correctly without reverse-engineering the code.

Schema documentation that stays in sync with intent

A data dictionary tells everyone what each column means, what it can hold, and what rules govern it. This builder turns a list of fields into a clean Markdown table — name, type, nullability, default, description, and validation — ready to drop into a README or wiki.

How it works

You name the table, then document each field with its data type, whether it is nullable, a default value, a plain-language description, and any validation rules. The tool escapes pipe characters in your text so they do not break the table, then renders a GitHub-flavoured Markdown table with one row per field and a header row. Nullability is shown as a clear Yes or No. Because the output is standard Markdown, it renders correctly in GitHub, GitLab, Notion, and most documentation systems without any reformatting.

Tips and example

  • Use canonical type names from your database — VARCHAR(255), BIGINT, TIMESTAMPTZ — so the dictionary matches the real schema.
  • Write descriptions for a newcomer: explain the business meaning, not just the type.
  • Capture validation the type cannot express, like must match email regex or 0 < amount <= 10000.
  • Keep one dictionary per table so each stays focused and easy to review in a pull request.