Opening an ER1 File

The ER1 file type is primarily associated with ERwin Data Modeler.

ER1	File extension: ER1
	File type:	proprietary data model file

What is an ER1 file

ER1 files mostly belong to ERwin Data Modeler. ER1 files are used by ERwin Data Modeler to save a database design. These files store the structure of a data model including tables, relationships, and constraints.
This file type works as follows:

Contains a visual representation of a database schema

Holds internal settings and detailed metadata for the model

Requires ERwin software to open and edit the model accurately

FilExt.com note: More information is available on the ERwin website.

How do you open ER1 files?

You need a suitable software like ERwin Data Modeler to open an ER1 file. Without proper software you will receive a Windows message "How do you want to open this file?" or "Windows cannot open this file" or a similar Mac/iPhone/Android alert. If you cannot open your ER1 file correctly, try to right-click or long-press the file. Then click "Open with" and choose an application. You can also display a ER1 file directly in the browser:. Just drag the file onto this browser window and drop it.

Online ER1 Text Viewer

Choose your .er1 file to analyze

or drag and drop it here

Online File Viewer

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Programs that open and convert ER1 files:

ERwin Data Modeler
See the previous paragraphs to learn more about the main application. ER1 files are often referred to as ERwin Data Modeler databases because this type of file is primarily created or used by this software.
AllFusion ERwin (Data) by Computer Associates International, Inc.
AllFusion ERwin Data Modeler is a data modeling solution that can help you create and maintain databases, data warehouses and enterprise data models. The identifying characters used for this association are - Hex: 56, ASCII: V.
Visible Advantage

ER1 file format:

To view or edit ER1 files you need to know the file format, because it determines how the data in this file is stored. The file format can be deduced from the file extension and the signature. Frequently, however, one file extension is used by different programs for different file formats, and one file format for different file extensions. So you need a detailed analysis of a file to find out the format and the associated program. Our evaluation of the ER1 files is as follows:

The ER1 file ending mainly uses a special format. The two most common formats are as follows:

96% of all ER1 files belong to AllFusion ERwin data. These files are binary files, so they do not contain text, but only cryptic characters. The average file size is 390 KB with most files being between 54 KB and 2 MB in size. The file type was used 20 years ago but is still in use today. The files contain the following words: ERwi, <Main Subject Area>5j, Erwin@@ and pEObj. Such files are related to model, data, diagram, modelo and schema.

The remaining 4% of all ER1 files are different files with different signatures. Drag & drop your file here to see the file format and a preview of your ER1 file!

Technical Data for ER1 File Extension

File classification:

Database

Identifier:

Hex: 56, ASCII: V (provided by TrID database)

Related files:

erx, erd, ddl, er2, erwin, ecr1, bk1, er2v, er, rar, rpt, eri, ckp, xml, sql

The following listing is compiled from the database produced by the 'Associate This!' program, selected data from the main FILExt database and file extension information submitted by users.

ProgramID: ER1File
EXEFile: %ProgramFiles%\Computer Associates\ERwin 4.0\mmopn32.exe %1

ProgramID: ER1File
EXEFile: %ProgramFiles%\CA\AllFusion ERwin Data Modeler\mmopn32.exe

ProgramID: MMOPN
EXEFile: %ProgramFiles%\PLATINUM\ERwin ERX 3.5.2\MMOPN32.EXE

an er1 proprietary data model file is a special file format and should only be edited and saved with the appropriate software.

How to solve problems with ER1 files

Associate the ER1 file extension with the correct application.
Update your software that should actually open proprietary data model files. Because only the current version supports the latest ER1 file format. Search, therefore, e.g. on the manufacturer website after an available ERwin Data Modeler update.
To make sure that your ER1 file is not corrupted or virus-infected, get the file again and scan it with Google's virustotal.com.
Click here to open your .ER1 file online - secure, fast, and no downloads needed.