Hi, @MohannadSh1996
For import connection, during the initial Get Data experience, the set of tables selected each define a query that will return a set of data. Upon load, all of the data defined by those queries will be imported into the Power BI cache.
For DirectQuery connections, during the initial Get Data experience, the source is selected. For relational sources, a set of tables are selected and each still define a query that logically returns a set of data. Upon load, no data is imported into the Power BI store.
I'd like to suggest you refer to the blog about what makes up a pbix file. The data model file with import mode is much larger than the one in DirectQuery mode. And visuals will also increase the size.
About how to reduce the size for import mode, you may refer to the document .
Best Regards
Allan
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