Very often yes, in this sort of context, 'base' needs to be understood as 'base de données' — especially when associated with 'enrichissement', which is a term particularly used with databases in a marketing context.

Your wider context really ought to make it clear whether 'base' has the rather more abstract sense of 'base', or the much more concrete one of 'database' — especially if there is any mention of what they do with it, for example?

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Note added at 2 heures (2016-12-20 17:47:14 GMT)
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In a later one of Asker's questions, we read:

"Base annonceur enrichie"

Here is the context we needed for you this question: we now know that the 'base annonceur' is 'enrichie', which confirms the sense of 'database'!