WHITE PAPER PowerDesigner® 15.3 vs. Computer Associates ERwin 7.3 www.sybase.com TABLE OF CONTENTS 1 Introduction 10 Database Support 1 Product Overviews 12 Repository (Collaborative Modeling) 1 ERwin Data Modeler 7.3 12 CA ERwin Model Navigator 1 PowerDesigner 15.3 12 Sybase PowerDesigner Viewer 2 User Interface Differences 13 Sybase PowerDesigner Portal 3 Modeling Features 13 Extensibility and Customization 4 Required Features for a Data Modeling Solution 14 Business Process Modeling 4 Model Types 15 Object Oriented Modeling 5 Conceptual > Logical > Physical > 15 Enterprise Architecture Modeling Logical > Conceptual 15 Dependency Matrices 6 Model Comparisons and Merges 16 Projects 7 Impact Analysis 16 Framework Matrices 9 Reverse / Forward Engineering 17 Summary 9 Modeling Notation 17 About the Author 10 Import / Export TABLE OF FIGURES 4 Figure 1 PowerDesigner Orthogonal Layout 11 Figure 9 PowerDesigner Oracle 6 Figure 3 PowerDesigner LDMTools Datatype Examples 8 Figure 4 ERwin Impact Analysis 14 Figure 12 PowerDesigner Allows Data to be 8 Figure 5 PowerDesigner Impact Analysis Assigned to Business Processes 11 Figure 6 PowerDesigner Oracle Physical Options INTRODUCTION When a project requires data modeling, there is a choice of several different products. Two market-leading products are ERwin (from CA) and PowerDesigner (from Sybase). Both will allow a modeler to create data models, reverse engineer databases, document database systems, create basic reports and create/modify diagrams in a Windows- standard manner. If an organization needs to create a database one time, generate the script to build it and never modify it again, then the best choice would be the product with the least acquisition cost. However, it is rare that an organization needs to create one database and leave it alone. As a business’ needs get more complex, the products reviewed in this paper quickly diverge. There is one clear winner: PowerDesigner. PRODUCT OVERVIEWS With the tools reviewed, there were similarities. Both modeling tools reviewed provide a drawing canvas and a navigator or explorer and a log window. Toolbars can be turned on or off, but only PowerDesigner allows for toolbar customization. Both tools have undo/redo capabilities. These are Windows applications and, as such, are intuitive from a user-experience perspective. Please see the table for differences in user-experience features following the vendors’ descriptions. ERwin Data Modeler 7.3 CA states “CA ERwin Data Modeler is a data modeling solution that enables you to create and maintain databases, data warehouses and enterprise data resource models. These models help you visualize data structures so that you can effectively organize, manage and moderate data complexities, database technologies and the deployment environment.” When I made an attempt to download ERwin, I found that the link on the website was broken. I called CA to request an evaluation copy of ERwin. After gathering my information, I was told that a salesperson would call me back. I never received a phone call from a salesperson. Two days later, I tried the link again and was able to successfully obtain an evaluation copy—good for 25 entities and 15 days. Installing Data Modeler seemed to work correctly. However, it did not create a Program Group in Windows, nor did it create a desktop link for starting the product. In order to use the modeling tool, I needed to navigate through the Windows folder hierarchy to find the program. PowerDesigner 15.3 Sybase “PowerDesigner uniquely combines several standard modeling techniques (UML, Business Process Modeling and market-leading data modeling) together with leading development environments, such as .NET, Workspace, PowerBuilder, Java, and Eclipse, to bring business analysis and formal design solutions to the traditional software development lifecycle. And it works with more than 60 RDBMS.” The ability to download the fully functional evaluation version of PowerDesigner 15 was provided from Sybase’s website. Installation was flawless. 1 User Interface Differences FEATURE POWERDESIGNER ERWIN Model Organization Yes, a full workspace that can be No. The model explorer within the saved independently from the tool only allows visibility into one models. Multiple models and model model at a time, regardless the types can be open simultaneously. number of open models. Workspace Yes—this can be saved independently No. from the models. Full flexibility and organization is provided. Multiple Diagrams within a Model Yes. Yes. Subject Areas in a Model Yes, via UML standard packages— Yes, but only one level. allows nesting. Object Placement Standard windows controls Standard windows controls Model Layouts Auto layouts include Basic, Under Format->Preferences, there is a Hierarchical, Organic, Orthogonal, “layout entire diagram” button but it Circular, Tree with scope of selected did not work, even when tables were symbols or all symbols. stacked on each other. Freeform Text Yes. No. Customize Toolbars Yes. No. Edit Text Directly on Graphic Yes. Yes. Page Grid Yes. Yes. Find Objects Yes. Yes. Product Documentation Yes, there are PDF versions of the Yes. documentation as well as full documentation online at http://sybooks.sybase.com. Undo/Redo Yes, unlimited. Yes and when using the repository, the undo/redo is maintained across modeling sessions. Zoom in/out Yes. Yes. 2 Modeling Features FEATURE POWERDESIGNER ERWIN Conceptual, Logical and Yes No Physical Models Naming Standards Yes Yes through templates Shortcuts to Objects in Other Models Yes No Templates for Model Creation Yes Yes Check Model (Validation) Yes—customizable to include user- Yes defined constraints such as tables must have three columns. Multidimensional Modeling Yes, extensive Yes Generate Test Data Yes No Impact and Lineage Analysis Yes No Object Oriented Model Yes No Business Process Model Yes No Enterprise Architecture Model Yes No Projects and Framework Matrices Yes No User Profiles Yes No Mapping Tool (Connections between Yes No objects in different models) Inter-Model Generation & Extensive, CDM-LDM-PDM, including Yes, only with LDM-PDM Synchronization other model types 3 Figure 1: PowerDesigner Orthogonal Layout REQUIRED FEATURES FOR A DATA MODELING SOLUTION Model Types To fully model a system, it is necessary to combine business analysis with technology implementations. Where data modeling is concerned, an organization must create conceptual data models, logical data models and physical data models. A conceptual data model (CDM) is usually in the form of an entity-relationship diagram, however it is purely data and relationships. A CDM is not relational. It is developed in order to understand, capture, and analyze the business needs from a data perspective. These models will be devoid of implementation details (data storage structures) or software constraints. Entities, attributes and identifiers are found in a CDM. Additionally, the relationships and inheritances that connect the objects, or artifacts, exist in the CDM. The CDM is a higher-level business model. Some of the relationships might be one-to-many yet some might be many-to-many. The CDM will typically be created prior to an LDM for a new system. The CDM might also be used for an existing system where the technology needs to be verified with the business. Once a CDM has been created, a modeler should be able to generate a logical data model (LDM) from it. The LDM is quite similar to the CDM in terms of the objects that are contained therein. However, the beginning of physical data storage is modeled in the LDM. Many-to-many relationships are not permitted in an LDM so they become intermediate entities. One-to-many relationships become primary key-foreign key identifiers. LDMs illustrate the logical entity types, the data attributes describing the entities and the relationships between the entities. A CDM does not have foreign-key constraints—these are created when a CDM is used to generate an LDM. Additionally, while a CDM supports a many-to-many relationship, the LDM does not permit many-to-many. Since the LDM is relational, many-to-many relationships cannot exist as many-to-many violates relational storage concepts. The LDM is relational but the CDM can transform to different types of logical models (hierarchical, object-oriented, and relational) so the CDM is better to represent the use of the data by the business. 4 The physical data model (PDM) would typically be created after the LDM. This model will be used to design the schema of the database that will be used for the system. Entities become tables, attributes become data columns and the relationships will be implemented in the database-specific structures (referential integrity, stored procedures). When creating or generating a PDM, the specific database is chosen (Oracle 11i, Sybase ASE 15, Microsoft SQL Server are several choices). The PDM is frequently used to generate the data description language (DDL) that will allow for database creation or modification. The LDM and the PDM are similar but vastly different in terms of the level of detail each supports. The LDM is used to explore domain concepts with the business stakeholders; the PDM is used to create and maintain the database. Multiple PDMs can be generated from a single LDM—this can be useful for database migrations, creation of production and development databases or application migrations. A modeling tool should provide the ability to model at any level, with generation to the other model types. All artifacts should be linked to their corresponding objects in the other models (for example, the entity “Customer” in the CDM should be linked to the “Customer” entity in the LDM as well as the “Customer” table in the PDM). All linkages should be maintained in the modeling tool so that a proposed change in an object can be analyzed before it is changed. Conceptual > Logical > Physical > Logical > Conceptual A data modeling tool MUST support round-trip engineering. Whether a modeler is starting from a conceptual model or reverse engineering a database into a physical model, a tool is useless unless it can support all aspects.