I was handed down an Excel file consisting of 47,000 rows and 20+ columns of
data. In each column, there is an enormous amount of repetition. The file is
over 20 MB and runs slowly.

Because of reasons beyond my control at work, I cannot use MS Access to
handle this data. So, I would like to create several tables containing the
unique values that repeat so frequently and essentially structure the data
like I would in Access with various relationships between fields.

How can I (at least somewhat) automate this task to replace the cell values
with references to another cell on another sheet? For example, replace every
occurrence of "LOS ANGELES, CA" in a certain column to, perhaps, whatever
cell "LOS ANGELES, CA" exists in in Sheet 2, Column A. I could be wrong but
some sort of vlookup seems like it might work for this.

Thanks.