1. A computer implemented method to develop a data model, comprising: upon receiving an entity data model extensible markup language (EDMX) file, displaying contents of the EDMX file including one or more elements, one or more attributes, and one or more attribute values via a text editor at an integrated development environment (IDE); based on an input received to modify the one or more attribute values via the text editor, displaying the modified one or more attribute values in an entity-relationship (ER) editor by instantiating a graphical model associated with the IDE; and based on an input received to modify the one or more attribute values on the ER editor, displaying the modified one or more attribute values in the text editor by instantiating a text editor model associated with the IDE.