SqlSpec is a database documentation tool that generates documentation about all the objects (tables, views, stored procedures, triggers, indexes, constraints, functions, etc) in your database. It has both GUI and command-line interface. It enables you to generate entity-relation diagrams.
                            
                            
                                
        
                                                
                        | Desktop/Cloud: | Desktop | 
                                                                
                        | ER Diagram: |   | 
                                                                
                        | Export: | CHM,HTML | 
                                                                                            
                        | Metadata stored in: | Database metadata | 
                                                                
                        | Commercial: | Commercial | 
                                                                
                        | Free edition: |   | 
                                                                
                        | Notable features: | Documents also Analysis Services, Reporting Services, Integration Server | 
                                                                
                        | Runs on: (for desktop): | Windows |