Hi Phillipe

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>What is the exact "relation" between DataSession and DataEnvironment?
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A dataEnvironment is a container for cursors and relationships in a Form. A DataSession is a "work area" completely independent of other datasessions insofar as what is opened and what relationships are defined.
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>My question is: Does the form DataEnvironment exactly match its private DataSession? In other words, are the Data in the DE corresponding exactly to the data of the private datasession? If I switch the dataEnvironment at runtime in my form, will the DataSession remain the same or not? Have I got ONE DE for ONE Datasession and vice versa?
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When a DE is instanced with a private datasession, a new datasession is created. If you instance a new DE at runtime it will instance a new datasession.