What's the Best Practice for End User to Mass Upload Element Entry?

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What's the Best Practice for End User to Mass Upload Element Entry?

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Our goal here is to enable a tool for end user to mass upload element entries. Here are different options we considered and none is acceptable by our end users. Does anyone allow your end users to manage the mass upload of element entry, if so how to achieve that? Thanks for sharing your ideas.

1.    HSDL: This is not that user friendly actually, (no need to mention HDL as there is no way end user can use it), see as attached, as it requires:

a.     Assignment Number: because there are a lot of rehires, legal entity transfers and so on, so employee may have multiple assignments, like -2 or -3. This is hard for end user to figure out, so I created a report to pull the latest assignment and end user needs to vookup and get the assignment ID, which is the way too much;