Code generation technology can significantly improve productivity and software quality. However, due to limited financial and human resources in most of small and medium software enterprises, there are many challenges when leveraging code generation approaches to large-scale software development. In this paper, an operational pattern based code generation approach is proposed for rapid development of domain-specific management information system. We demonstrate the approach with details: (I) semi-automatically extracting operational patterns from requirement documents, (II) building feature models to manage the commonalities and variability of each operational pattern, (III) mapping operational patterns into skeleton code with a template-based code generation technique, etc. Then we conduct an industrial case study in asset information management domain at CancoSoft Company for about 2 years, to analyze its feasibility and efficiency. 14 operational patterns are successfully extracted from 355 initial key phrases, and a code generator is implemented and applied to develop new Web applications. Preliminary findings show that the software development based on our approach yields a nearly 30% higher productivity as compared to traditional software development. Through code analysis, we find that around 70% of code can be automatically generated, and the generated code is also effective.