Database Schema Planner
Plan entities, typed fields, and relationships with an editable schema view. Export a structured JSON specification or Mermaid ER diagram, free in your browser.
Schema export
{
"entities": [
{
"name": "users",
"fields": [
{
"name": "id",
"type": "uuid",
"required": true,
"unique": true
},
{
"name": "email",
"type": "string",
"required": true,
"unique": true
}
]
},
{
"name": "projects",
"fields": [
{
"name": "id",
"type": "uuid",
"required": true,
"unique": true
},
{
"name": "owner_id",
"type": "uuid",
"required": true,
"unique": false
},
{
"name": "title",
"type": "string",
"required": true,
"unique": false
}
]
}
],
"relationships": [
{
"from": "users",
"to": "projects",
"cardinality": "one-many"
}
],
"note": "Conceptual schema. Relationships do not automatically create foreign keys, indexes, or migrations."
}Export text stays in English; your input is kept as entered.
No signup. No AI credits. This tool assembles your output in your browser.
From an idea to something useful.
- 01
Add entities and their typed fields.
- 02
Connect entities with relationship cardinalities.
- 03
Review the schema cards and export JSON or a Mermaid ER diagram.
A little context.
This conceptual schema planner records entities, field types, required values, unique values, and relationships. Exports are design artifacts rather than executable migrations. Entity and field names use simple identifiers so diagrams remain valid and easy to translate into your chosen database.
Good questions.
Does this create database tables?
No. It exports a conceptual model. Translate types, constraints, indexes, and relationships into reviewed migrations for your database.
Is a relationship the same as a foreign key?
No. The JSON and diagram describe a relationship, but do not automatically add or enforce foreign-key fields. Add those fields explicitly during implementation.