Free Online SQL Table Schema Visualizer

About the SQL Schema Visualizer

A relational schema is easiest to understand when you can see the tables and the links between them. This tool reads CREATE TABLE statements and turns them into a set of table cards and a relationship list. It works with MySQL, PostgreSQL, SQLite, MariaDB, and most standard SQL dialects because it focuses on the common declaration syntax rather than vendor-specific features. Columns, types, primary keys, foreign keys, and common constraints are extracted and displayed without connecting to a database.

The parser first removes line comments and block comments, then splits the input into individual statements while respecting quoted strings. For every statement that begins with CREATE TABLE, it isolates the parenthesized body, splits the definitions on top-level commas, and examines each line. Table-level constraints such as PRIMARY KEY (id), FOREIGN KEY (user_id) REFERENCES users(id), and UNIQUE (email) are recognized, as are inline declarations such as id INT PRIMARY KEY and user_id INT REFERENCES users(id). Quoted identifiers wrapped in backticks, double quotes, or square brackets are cleaned up so the cards stay readable.

The summary panel counts tables, columns, and foreign-key relationships. The warnings panel points out common modeling gaps: a table without a primary key, a foreign key that points at a table missing from the pasted batch, a duplicate table name, or a statement that produced no columns. These are warnings rather than proof of a broken schema, because the input may be an excerpt, a migration fragment, or a vendor dump with tables defined elsewhere. The relationship list is especially useful for spotting missing indexes on join columns and for checking that cascade behavior matches your expectations.

Everything is processed locally in the browser. The tool does not execute SQL, does not validate against a live catalog, and does not understand advanced constructs such as table partitioning, generated columns, or inheritance. It is a reading aid for code review, migration planning, documentation, and onboarding, not a replacement for your database's own schema inspection commands. Very large dumps may take a moment to parse, and extremely complex default expressions can be displayed only partially.

How to use this tool

1. Paste one or more CREATE TABLE statements into the input box.
2. Click Visualize schema or wait for the automatic parse.
3. Review the table cards, the relationship list, and any warnings.
4. Copy the text summary or download it for a ticket or design document.

Frequently asked questions