In Astah Professional, you can convert ER diagrams to UML class diagrams.

ER diagram converted to a UML class diagram in Astah Professional
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Convert ER diagram to Class diagram

  1. In the Structure Tree, select [Convert to Class Diagram] from the ER diagram’s pop-up menu.
    Convert to Class Diagram menu
  2. The diagram and all the model elements in it are converted to a class diagram, which appears in the tree view.
    Converted UML classes in the tree view
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Convert ER models to UML models

In Astah Professional, instead of converting ER diagrams to class diagrams one by one, you can convert multiple diagrams and models at once.

  1. Go to [Tools] – [ER Diagram] – [Convert ER Model to UML Model].
    Convert ER Model to UML Model menu
  2. Select the ER models you want to convert, then click [Create].
    Selecting ER models to convert to UML
  3. The converted models are added to the tree view. To open a converted diagram, select [Open Diagram] from its pop-up menu in the tree view.
    Open Diagram menu for a converted diagram
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Convert Rule

ER entity attribute converted to a UML class attribute

ER data types are converted as shown below. Other data types are shown as String on the diagram, but the original data type is kept as a tagged value (see Data Type).

ER Data TypeConvert to
INTint
BITboolean
NUMERICint
CHARchar or String (char if its Length/Precision is empty or 1)
DATEDate
DOUBLE_PRECISIONdouble
FLOATfloat
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Data Type

When you convert an ER diagram to UML, the data type of each ER entity attribute is saved as a tagged value of the UML attribute.

For example, take the ER entity below:
Sample ER entity with a VARCHAR(20) attribute

Converting it gives the following UML class:
UML class converted from the ER entity

VARCHAR(20) is converted to String, but the original data type is kept as a tagged value. Open the [TaggedValue] tab to see it.
Original ER data type in the TaggedValue tab

If you convert an ER diagram to UML and then back to an ER diagram, you can run this script with the Script Editor to restore the original data types in the final ER diagram.