Visualize your database schema instantly. Convert SQL `CREATE TABLE` statements into clear Entity-Relationship diagrams.
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Designing and documenting databases is a critical step in software development, but manually drawing diagrams is tedious. Our ER Diagram Generator is a specialized developer tool that parses your raw SQL CREATE TABLE scripts and instantly renders them as interactive Entity-Relationship Diagrams (ERDs). Whether you are optimizing a legacy database, planning a new feature, or learning schema design, this tool provides immediate visual feedback on your database structure.
Forget about drag-and-drop tools. Just paste your CREATE TABLE statements, and our engine automatically identifies tables, columns, and relationships to generate a professional diagram in milliseconds.
Security is paramount. Your database schema contains sensitive architectural details. Unlike other tools, we do not send your SQL to any server. All parsing, processing, and rendering happen strictly within your browser.
CREATE TABLE statements. Ensure you include PRIMARY KEY and FOREIGN KEY definitions.||--o{ indicates a "One-to-Many" relationship.Entity-Relationship Diagrams are the blueprint of your database architecture. They reveal how tables connect, how data flows between entities, and where potential bottlenecks or design flaws might exist. A well-designed schema minimizes redundancy, ensures data integrity through proper foreign key constraints, and makes queries more efficient. By visualizing your database structure, you can quickly identify missing indices, circular dependencies, orphaned tables, or overly complex join paths that could impact performance.
This relationship type is relatively rare but serves specific purposes. A classic example is a User table with a corresponding UserProfile table. This separation is useful when you have optional or sensitive data that doesn't need to be loaded with every user query. Implementation typically uses a unique foreign key constraint to ensure each record in one table corresponds to exactly one record in another.
The most prevalent relationship pattern in relational databases. Consider a blogging platform: one User can author many Posts, but each post belongs to exactly one user. In ER diagrams, this is represented by crow's foot notation (||--o{), where the "crow's foot" indicates the "many" side. The foreign key always resides in the "many" table, pointing back to the primary key of the "one" table.
This relationship requires an intermediary junction table (also called a bridge or associative table). For instance, in an e-commerce system, Products can belong to multiple Categories, and each category contains multiple products. The solution is a ProductCategories table with foreign keys to both tables. In ER diagrams, this appears as two separate one-to-many relationships converging on the junction table.
When designing your database schema, always define explicit foreign key constraints rather than relying on naming conventions alone. While a column named user_id suggests a relationship, the database engine cannot enforce referential integrity without a formal constraint. Use meaningful table and column names that clearly indicate their purpose. Consider adding indices on foreign key columns to improve join performance. Finally, normalize your data to eliminate redundancy, but don't over-normalize to the point where simple queries require excessive joins.
The parser strictly looks for FOREIGN KEY constraints. If you only have columns named user_id but no constraint definition, the tool cannot infer the link. Add FOREIGN KEY (user_id) REFERENCES users(id) to your SQL.
The tool is optimized for standard SQL (ANSI), MySQL, and PostgreSQL CREATE TABLE syntax. It handles data types, primary keys, and basic constraints. Dialect-specific features like storage engines or partitions are generally ignored to focus on the logical schema.
Currently, we support SVG export because it scales perfectly for print and web. You can easily convert SVG to PNG or JPG using standard image tools if needed.