DBML - Database Markup Language

DBML (database markup language) is a simple, readable DSL language designed to define database structures.

Benefits

• It is simple, flexible and highly human-readable
• It is database agnostic, focusing on the essential database structure definition without worrying about the detailed syntaxes of each database
• Comes with a free, simple database visualiser at dbdiagram.io

Command-Line Interface (CLI)

(coming soon) A dbml-to-sql generator to generate SQL from .dbml file

• Allow users to integrate DBML with their workflow
• Each project will have one or several .dbml files to define database schema
• DBML-CLI will be used to export .dbml files to specific SQL (MySQL, PostgreSQL, etc), JSON format, etc
• DBML-CLI could also be used to generate .dbml files from other SQL or JSON files

Example

Example of a database definition of a simple blogging site:

Table users {
    id integer
    username varchar
    role varchar
    created_at timestamp
}

Table posts {
    id integer [primary key]
    title varchar
    body text [note: 'Content of the post']
    user_id integer
    created_at timestamp
}

Ref: posts.user_id > users.id // many-to-one

Is this similar to SQL DDL?

Not quite. Despite its name (data "definition" language), DDL is designed mainly to help physically create, modify or remove tables, not to define them.

DDL also comes with a few more drawbacks:

• It is hard to read, especially when trying to add multiple column/table settings together.
• It is database specific (Oracle vs PostgreSQL vs MySQL, etc)
• Since it is imperative (vs declarative), to fully reconstruct a table definition you have to trace through all the code (instead of focusing on just 1 single section).

How to generate SQL from DBML?

1. Go to dbdiagram.io
2. Type up your DBML code
3. Go to Export > SQL (choose your DB)

DBML Full Syntax Docs

Please refer to the docs section on the website.

Syntax Consistency

DBML is the standard language for database and the syntax is consistent to provide clear and extensive functions.

• curly brackets {}: grouping for indexes, constraints and table definitions
• square brackets []: settings
• forward slashes //: comments
• column_name is stated in just plain text
• single quote as 'string': string value
• double quote as "column name": quoting variable
• backtick `: function expression

Community Contributions

Emacs Mode for DBML

(Contributed by ccod): https://github.com/ccod/dbd-mode