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DIAGRAM 17

# ConceptDraw DIAGRAM ER Diagram Tool

The main tool of domain modeling at the stage of conceptual design is the Entity-relationship model, also called ER-model. Modeling domain data structures is based on the usage of graphical tools — ER-diagrams (Entity-Relationship diagrams). Simply put, it is a visual representation of relationships between entities.

The core concepts of ER Diagram are entity, attribute and relationship. An entity is an object of the real world that can exist independently. An entity has instances which differ in attribute values and allow unambiguous identification. An attribute is a property of the essence. For example, the entity named Book is characterized by attributes such as author, title, price, publishing house, edition, number of pages. Specific books are instances of the book entity. These instances vary in the values of these attributes and are uniquely identified by the attribute "name". Attribute that uniquely identifies the instance of the entity is called the primary key. It may also be a composite key, which is a combination of several attributes.

A very important feature of the entity-relationship model is that it can be represented as a graphical diagram. This greatly facilitates the subject area analysis. There are several notations used to represent entity-relationship elements, like Crow’s foot notation, or Chen notation, and each has its pros and cons.

Example 1. ER Diagram

The entity on the ER-diagram is represented in the form of a rectangle, which indicates its name. Relationship is the interaction between entities, which is characterized by degree which counts how many entities are involved in the relation. The relationship between the two entities is called binary, and the relationship between more than two entities is ternary. Attributes, entities and relationships are connected by straight lines. Relation is shown in the form of a diamond. When creating a diagram, you can follow a few obvious steps. First, you need to identify entities and relationships among them. The following step is to identify the semantic information in the sets of relations (for example, whether a certain set of connections is a 1:n relation). Then you should define relationships cardinalities and determine attributes and their values sets. The final step is to organize the data in the form of entity-relationship connections.

As an example, let’s imagine a database designed for storing information about some bank activities. The bank has affiliates, which are controlled by managers. Customers of the bank have different types of accounts — current, term, demand, deposit, card account. Branches handle these accounts. The described domain will be called Bank. Let’s determine four entities: the Affiliate, the Manager, the Account, the Customer and some relations among them: the Manager controls the Affiliate; the Affiliate handles the Account; the Customer has the Account.

ConceptDraw PRO v5 with Entity-Relationship Diagram (ERD) solution serving as ERD software allows you to visually create Entity Relationship diagrams (ERDs) for various database systems, it supports ODBC-compatible databases (Oracle, MS SQL, InterBase, MySQL, MS Access, Firebird and others). The built-in scripting language allows to connect to ODBC-compatible databases and automatically generate the structure of a database (reverse engineering of the database structure).

Example 2. ConceptDraw ER Diagram Tool

ConceptDraw ER Diagram Tool works across any platform, meaning you never have to worry about compatibility again. ConceptDraw PRO v5 allows you to make Entity-Relationship Diagram (ERD) on PC or macOS operating systems.

When creating an ERD our ERD software considers individual database options such as referential integrity, constraints, domains, triggers, stored procedures, functions, packages, views, sequences, synonyms etc.

ConceptDraw PRO v5 is a very easy-to-use and intuitive database design tool and ER Diagram tool which can save you hundreds hours of work. Entity-Relationship Diagram (ERD) solution contains 2 libraries with 45 predesigned vector graphic elements, collection of professional ERD samples, examples and templates.

ConceptDraw PRO v5 is excellent choice of database designers for modeling, reverse and forward engineering of relational databases. It is not only an excellent tool for ER Diagram, but also the one that allows you to reverse engineer already existing database structures, create detailed HTML, PDF or PPT reports.

Example 3. ER Diagram (ERD)

The ER Diagram samples you see on this page were created in ConceptDraw PRO v5 using the Entity-Relationship Diagram (ERD) Solution. They successfully demonstrate solution's capabilities and professional results you can achieve. An experienced user spent 10 minutes creating every of these samples.

Use the Entity-Relationship Diagram (ERD) Solution for ConceptDraw PRO v5 software to create your own professional looking ER Diagrams quick, easy and effective, and then successfully use them in your scientific or education activity.

All source documents are vector graphic documents. They are available for reviewing, modifying, or converting to a variety of formats (PDF file, MS PowerPoint, MS Visio, and many other graphic formats).

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UML Timing Diagram as special form of a sequence diagram are used to explore the behaviors of objects throughout a given period of time. ConceptDraw has 393 vector stencils in the 13 libraries that helps you to start using software for designing your own UML Diagrams. You can use the appropriate stencils of UML notation from UML Timing library.
Picture: UML Timing Diagram, Design Elements
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The Entity-Relationship Diagram (ERD) Solution from the Software Development Area for ConceptDraw Solution Park extends ConceptDraw DIAGRAM vector graphics and diagramming software with the ability of drawing the Entity Relationship Diagrams for visually describing the databases with Crow’s Foot and Chen's notation icons.
Picture: Entity Relationship Diagrams
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An abstract representation is usually the first thing you will need while developing a database. To understand the ways that databases are structured, you should look through entity-relationship diagram examples and see the notations features and attributes. With an entity-relationship model you can describe a database of any complexity. This Entity-relationship diagram is a tool for software developers. It enables every element of database to be managed, communicated and tested before release. This ERD was created using symbols advocated by Chen's notation. Because of a linguistic origin of the Chen’s notation, the boxes representing entities could be interpreted as nouns, and the relationships between them are in verb form, shown on a diagram as a diamond.
Picture: Entity Relationship Diagram Examples
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A database is a data collection, structured into some conceptual model. Two most common approaches of developing data models are UML diagrams and ER-model diagrams. There are several notations of entity-relationship diagram symbols and their meaning is slightly different. Crow’s Foot notation is quite descriptive and easy to understand, meanwhile, the Chen notation is great for conceptual modeling. An entity relationship diagrams look very simple to a flowcharts. The main difference is the symbols provided by specific ERD notations. There are several models applied in entity-relationship diagrams: conceptual, logical and physical. Creating an entity relationship diagram requires using a specific notation. There are five main components of common ERD notations: Entities, Actions, Attributes, Cardinality and Connections. The two of notations most widely used for creating ERD are Chen notation and Crow foot notation. By the way, the Crow foot notation originates from the Chen notation - it is an adapted version of the Chen notation.
Picture: ERD Symbols and Meanings
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You need design a Bank UML Diagram? Now, thanks to the ConceptDraw DIAGRAM diagramming and vector drawing software extended with ATM UML Diagrams Solution from the Software Development Area, you can design without efforts any type of Bank UML Diagram you want - Class, Activity, Communication, Component, Composite structure, Deployment, Interaction overview, Object, Package, Profile, Sequence, State machine, Timing, Use case.
Picture: Bank UML Diagram
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Structured-systems analysis and design method uses data flow diagrams to represent the process of data flowing through a system. Talking about this might be useless without a proper example of DFD for online store (Data Flow Diagram). This DFD example shows all the distinctness that a diagram can bring into a scattered data structure. Data flow diagrams are used to show how data is processed within some business processes. Making DFD is a common practice for business process modeling and analysis. This diagram represents the online store business flow. It describes inputs and outputs within online selling process and depicts the interactions between its participants. This DF diagram can be used by system analysts to create an overview of a business, to study and discover its inherent strengths and weak points.
Picture: Example of DFD for Online Store (Data Flow Diagram)
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UML Component Diagram Online Shopping. This sample was created in ConceptDraw DIAGRAM diagramming and vector drawing software using the UML Component Diagram library of the Rapid UML Solution from the Software Development area of ConceptDraw Solution Park. This sample shows the concept of the online shopping and is used for the understanding of the online shopping processes, of the online shops working processes, for projection and creating of the online stores.
Picture: UML Component Diagram Example - Online Shopping
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