Entity relationship diagram uml tutorial

Create a Database Model (also known as Entity Relationship diagram) - Visio

entity relationship diagram uml tutorial

Select first an element where a new Entity-Relationship Diagram to be contained as a child. Select Model | Add Diagram | ER Diagram in Menu Bar or select Add. An Entity Relationship Diagram (ERD) is a data model describing how entities In this tutorial, you'll learn what goes into an ERD and how to create one from a. Select first an element where a new Entity-Relationship Diagram to be contained as a child. Select Model | Add Diagram | ER Diagram in Menu Bar or select Add.

To start your database model diagram, do one of the following: Create a new model diagram from scratch If you don't have an existing database that you want to use as a starting place, you can start with a blank Database Model and add your own tables and relationships.

Entity Relationship Diagram

Click the File tab. On the Database tab, in the Manage group, click Display Options. In the Database Document Options dialog box, select the symbol set that you want to use and other table and relationship options, and then click OK. Use an existing database as a starting point If you have a database that you want to model so that you can understand it better or use it as a starting place for a new model, you can use the Reverse Engineer Wizard to extract the schema, or structure, of the database and build a new model.

Before you start the wizard: If you are reverse engineering a Microsoft Excel workbook, before you start the wizard you need to open the workbook and name the group or range of cells that contains the column headings. If you want to use more than one worksheet, just name the group of column cells in each worksheet. These ranges are treated like tables in the wizard. For more information about how to name a range of cells, see the topic in your Excel help titled Define named cell references or ranges.

For best results, set your default driver to the target database that you want to reverse engineer before you run the Reverse Engineer Wizard. This step ensures that the wizard maps the native data types correctly and that all the code that is extracted by the wizard is correctly displayed in the Code window.

On the Database tab, in the Model group, click Reverse Engineer.

ER Diagram (Entity-relatonship Diagram) | Astah User's Guide | posavski-obzor.info

On the first screen of the Reverse Engineer Wizard, do the following: Select the database driver for your database management system DBMS. Select the data source of the database that you are updating.

If you have not already created a data source for the existing database, click New to do so now.

  • ER Diagram
  • Create a Database Model (also known as Entity Relationship diagram)
  • Data Modelling with UML

When you create a new source, its name is added to the Data Sources list. When you are satisfied with your settings, click Next.

Follow the instructions in any driver-specific dialog boxes. For example, in the Connect Data Source dialog box, type the user name and password, and then click OK. If you use the ODBC Generic Driver, you may receive an error message that indicates that the reverse engineered information may be incomplete. Select the check boxes for the type of information that you want to extract, and then click Next. Some items may be unavailable appear grayed out because not all database management systems support all the kinds of elements that the wizard can extract.

Select the check boxes for the tables and views, if any that you want to extract, or click Select All to extract them all, and then click Next. If you are reverse engineering an Excel worksheet and don't see anything in this list, it is likely that you need to name the range of cells that contains the column headings in your worksheet.

If you selected the Stored Procedures check box, select the procedures that you want to extract, or click Select All to extract them all, and then click Next. Select whether you want the reverse engineered items to be added automatically to the current page.

entity relationship diagram uml tutorial

You can choose to have the wizard automatically create the drawing, in addition to listing the reverse engineered items in the Tables and Views window. If you decide not to have the drawing created automatically, you can drag the items from the Tables and Views window onto your drawing page to manually assemble the database model.

Review your selections to verify that you are extracting the information that you want, and then click Finish. The wizard extracts the selected information and displays notes about the extraction process in the Output window. This ability is limited to only VisioModeler 2.

entity relationship diagram uml tutorial

On the Database tab, in the Model group, click Import, and then click the model type. Type the path and file name for the model that you want to import, or click the Browse button to locate the model file, and then click Open. In the Import dialog box, click OK. Visio imports the file and displays its progress in the Output window. The imported tables are displayed in the Tables and Views window.

In the Tables and Views window, select the tables that you want to model, and then drag them onto the drawing page. After you create a database model diagram, the work of refining the diagram begins. You can add and customize tables and views, create relationships, and customize columns and data types.

Tables Use the Entity shape to create a table in your diagram. From either the Entity Relationship or Object Relational stencil, drag an Entity shape onto the drawing.

ER Diagram Representation

Double-click the shape to open the Database Properties window. Under Categories, click Definition and type a name for the table.

Under Categories, click Columns, type a name, and choose a data type. Select the Req'd check box for columns that can't have null values. Select the PK primary key check box for columns that uniquely identify each row in the database table. Columns Use the Database Properties window to add or change properties for columns, including data types and primary keys. Double-click the table in your diagram.

In the Database Properties window, under Categories, click Columns. Click in the first empty Physical Name cell, and type a name. To change the data type for a column, click the column's Data Type field, and then select a data type from the list or type it into the list.

Data Modelling with UML - Training Material

For example, you can type decimal 8,2 or char To prevent null values, select the Req'd check box. To specify that the column is a primary key, select the PK check box. To see more column properties in addition to those that appear when you click the Columns category, select the column and then click Edit. Relationships Relationships use primary and foreign keys to allow databases to match a row in one table with a row in a related table.

You can show those relationships in your diagram. In addition, you can set their cardinality for example, one-to-many and use either Crow's feet, Relational, or IDEF1X notation to show the cardinality.

How to Create Templates How to Draw a Database Model Diagram A simple tutorial help you learn how to draw a database model diagram for your database design and increase you possibilities of understanding and work more effective with our Database Model Diagram Software. Does anyone need a good tool to quickly and easily create a diagram for a database schema? Does anyone need a good database diagram tool to quickly and easily create the different UML entity relationship diagram, SQL database diagram, ERD database diagram, ER database diagram in a software package?

Edraw can be used to quickly create a wide rage of database diagrams: This simple tutorial will illustrate how to draw a database model diagram with the professional edition of Edraw max.

How to Draw a Database Model Diagram You can choose to use the Block Diagram and the Basic Drawing Shapes to draw your database model diagrams, but since there is a special template for Database Model diagram, we will look at that first.

Here is what your screen will look like at this point: Entity Relationship Template With the database model diagram template, you can create a new database model diagram by using either the relational or object relational modeling concepts. Use the Entity Relationship symbols to model databases.

entity relationship diagram uml tutorial

The entity relationship template includes entity, relationship, view, category and dynamic connector. Object Relationship Template Use the Object Relational shapes, which have additional shapes for working with types, to model databases. The object relationship template includes entity, relationship, type, table inheritance relationship, category to child relationship, view, category and dynamic connector.

Then you can add shapes by either dragging shapes from the above two templates or using the drawing tools. The entity shape looks like an excel cell and you can resize it and edit every cell in it. Move or resize the green selection handle to resize a shape.